Former W.S. Hatch CO. Facility ( HATCHCO ) Woods Cross, Utah … · 2019-12-03 · HATCHCO Est. 1936 P.O. BOX 50539 • AMARILLO, TEXAS 79159 • 806-354-5678 Former W.S. Hatch CO

HATCHCO Est. 1936

P.O. BOX 50539 • AMARILLO, TEXAS 79159 • 806-354-5678

Former W.S. HatchCO. Facility

( HATCHCO )

Woods Cross, Utah

FINALFOCUSEDFEASIBILITYSTUDY

July 2004

HDR Engineering, Inc.

KR

W.S. Hatch Co.Woods Cross, Utah

July 2004


FOCUSED FEASIBILITY STUDY n n n n i rFINAL REPORT DOCUMENT

TABLE OF CONTENTS

EXECUTIVE SUMMARY 1

1.0 INTRODUCTION 1-11.1 Purpose and Scope of the Focused Feasibility Study 1-11.2 Report Organization ;.. 1-11.3 Site Location 1-21.4 Ownership and Site Operations 1-2

2.0 SUMMARY OF REMEDIAL INVESTIGATION 2-12.1 Geology and Hydrogeology 2-1

2.1.1 Geology 2-12.1.2 Hydrogeology 2-12.1.3 Horizontal Hydraulic Gradient 2-22.1.4 Vertical Hydraulic Gradient 2-22.1.5 Slug Testing 2-2

2.2 Nature and Extent of Contamination 2-42.2.1 Surface Soils 2-42.2.2 Soil Gas Survey (SGS) Results 2-42.2.3 Subsurface Soils 2-52.2.4 Groundwater 2-52.2.5 Origin and Extent of Soil Contamination 2-62.2.6 Horizontal Extent of Groundwater Impacts 2-82.2.7 Vertical Extent of Groundwater Impacts 2-102.2.8 Occurrence of Dense Non Aqueous Phase Liquid 2-102.2.9 Off-Site Sources 2-12

2.3 Summary of Groundwater Contaminant Fate and Transport Modeling 2-132.4 Baseline Risk Assessment 2-15

2.4.1 Contaminants of Concern 2-152.4.2 Exposure Assessment 2-152.4.3 Toxicity Assessment 2-16

2.4.4 Risk Characterization 2-172.4.4.1 Hypothetical Future On-Site Trench Worker 2-172.4.4.2 Hypothetical Future On-Site Indoor Worker 2-172.4.4.3 Off-Site Residents 2-22

2.4.5 Ecological Evaluation and Characterization 2-22

3.0 SUMMARY OF PREVIOUS REMEDIAL MEASURES 3-13.1 Oil/Water Separator 3-13.3 Underground "Waste Oil" Storage Tank 3-13.4 Groundwater Remedial Efforts 3-2

4.0 REMEDIAL ACTION OBJECTIVES 4-14.1 Introduction 4-14.2 Contaminants of Concern 4-2

W.S. Hatch Co. i HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

4.3 Potential Exposure Pathways 4-24.4 Remediation Goals 4-2

5.0 APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS 5-1

6.0 SCREENING OF REMEDIAL TECHNOLOGIES 6-16.1 Introduction 6-16.2 General Response Actions 6-16.3 Environmental Media Targeted for Remediation 6-16.4 Technology Screening Criteria 6-26.5 Evaluation of Candidate Technologies 6-2

7.0 SCREENING OF REMEDIAL ALTERNATIVES 7-17.1 Waste Quantities 7-1

7.1.1 Soils 7-17.1.2 Groundwater 7-1

7.2 Remedial Alternatives 7-27.2.1 Alternative 1 - No Action 7-27.2.2 Alternative 2 - Monitored Natural Attenuation (MNA) w/Institutional

Controls ; 7-27.2.3 Alternative 3 - Surface Capping w/Institutional Controls 7-37.2.4 Alternative 4 - Soil Vapor Extraction w/Institutional Controls 7-47.2.5 Alternative 5 - Excavation w/Off-Site Disposal, Institutional Controls. 7-57.2.6 Alternative 6 -In-Situ Biological/Chemical Remediation w/Institutional

Controls 7-67.2.7 Alternative 7 - Groundwater Extraction w/Above Ground Treatment,

Institutional Controls 7-6

8.0 DETAILED ANALYSIS OF ALTERNATIVES 8-18.1 Introduction 8-18.2 Evaluation Criteria 8-18.3 Detailed Analysis of Remedial Alternatives 8-4

8.3.1 Alternative 1 - No Further Action 8-48.3.2 Alternative 2 - Monitored Natural Attenuation (MNA) w/Institutional

Controls 8-58.3.3 Alternative 3 - Surface Capping w/Institutional Controls 8-78.3.4 Alternative 4 - Soil Vapor Extraction w/Institutional Controls 8-98.3.5 Alternative 6 - Enhanced In-Situ Biological/Chemical Remediation

w/Institutional Controls 8-128.3.6 Alternative 7 - On-Site Groundwater Extraction w/Above Ground

Treatment, Institutional Controls 8-158.3.6.1 Alternative 7a - Treatment via Air Stripping 8-168.3.6.2 Alternative 7b - Treatment via Ultraviolet Oxidation 8-188.3.6.3 Alternative 7c - Discharge to POTW 8-20

9.0 COMPARATIVE ANALYSIS 9-19.1 Overall Protection of Human Health and the Environment 9-1

W.S. Hatch Co. ii HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

9.2 Compliance with ARARs :..., 9-19.3 Short-Term Effectiveness 9-29.4 Long-Term Effectiveness and Permanence 9-29.5 Reduction in Toxicity, Mobility or Volume through Treatment 9-29.6 Implementability 9-49.7 Cost 9-49.8 State Acceptance 9-49.9 Community Acceptance 9-4

10.0 REFERENCES 10-1

W.S. Hatch Co. iii HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

LIST OF TABLES

Table 2-1 Water Level Data - Unconfined AquifierTable 2-2 Vertical Grandient Calcualtion - October 2002Table 2-3 Slug Test ResultsTable 2-4 Total Organic Carbon AnalysisTable 2-5 COC Solubility Limits and Maximum Oserved ConcentrationsTable 2-6 Calibrated Transport Model ParametersTable 2-7 Summary of Toxicity ValuesTable 2-8 Summary of RME Risk Estimates and Hazard Indicies (Old TCE Slope Factor)Table 2-9 Summary of RME Risk Estimates and Hazard Indicies (Provisional TCE Slope

Factor)Table 2-10 Summary of CTE Risk Estimates and Hazard Indicies (Old TCE Slope Factor)Table 2-11 Summary of CTE Risk Estimates and Hazard Indicies (Provisional TCE Slope

Factor)Table 4-1 Preliminary Remediation GoalsTable 5-1 Chemical-Specific ARARsTable 5-2 Location-Specific ARARsTable 5-3 Action-Specific ARARsTable 6-1 Identifiation and Screening of Potentially Applicable Remedial Technilogies for

the Vadose Zone (source area)Table 6-2 Identifiation and Screening of Potentially Applicable Remedial Technilogies for

GroundwaterTable 7-1 Screening of AlternativesTable 8-1 Comparative Analysis of Alternatives

W.S. Hatch Co.Focused Feasibility Study Final Report

HDR Engineering, Inc.July 2004

LIST OF FIGURES

Figure No.1-1 Site Location1-2 Site Plan1-3 Historic Site Features Location Plan2-1 Geologic Cross-Section Traverse A - A'2-2 Geologic Cross-Section2-3 Water Table Contour Map (October 25, 2002)2-4 Surface Soil Sampling Results2-5 Soil Gas Sampling Results (5' depth)2-6 Soil Gas Sampling Results (15' depth)2-7 Soil Gas Sampling Results (25' depth)2-8 Off-Site Soil Gas Sampling Results (51 depth)2-9 Subsurface Soil Sampling Results

2-10 Direct-Push Groundwater Sampling Results2-11 Monitoring Well Groundwater Sampling Results (October 2002)2-12 Isoconcentration Contour Map of Chlorinated Hydrocarbons in Shallow Groundwater2-13 Compilation of Available Groundwater Chemistry Data2-14 MW-2S Concentration vs. Time Plot2-15 MW-3S Concentration vs. Time Plot2-16 MW-10S Concentration vs. Time Plot2-17 MW-12S Concentration vs. Time Plot2-18 MW-13S Concentration vs. Time Plot2-19 MW-14S Concentration vs. Time Plot2-20 Groundwater Map Showing Inferred Third-Party Contaminant Plumes2-21 Modeled Groundwater Contaminant Plume Attenuation in Year 2002, 2010, and 20252-22 Contour Map Showing Areas Exceeding MCLs in the Shallow Aquifer7-1 Inferred Potential Source Area7-2 Cap Liner System7-3 Soil Vapor Extraction7-4 Groundwater Extraction UV Oxidation System Schematic Design8-1 Groundwater Flow Model Particle Tracking Analysis

LIST OF APPENDICES

Appendix A Technical Memorandum on Applicability of Monitored Natural AttenuationAppendix B CostingAppendix C Vendor InformationAppendix D Capture Analysis Technical Memorandum

W.S. Hatch Co. v HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

LIST OF COMMONLY USED ACRONYMS

AOC Administrative Order on Consentbgs below ground surfaceBRA Baseline Risk AssessmentBTEXN benzene, toluene, ethylbenzene, xylenes, and naphthaleneCERCLA Comprehensive, Environmental, Response, Compensation and Liability ActCOC Containment of ConcernCOC(s) Chemical(s) of Potential ConcernCSF Carcinogenic Slope FactorCSF Cancer Slope FactorDCA DichloroethaneDCE DichloroetheneDNAPL Dense Non Aqueous Phase LiquidDQO(s) Data Quality Objective(s)EPA Environmental Protection AgencyFFS Focused Feasibility StudyFSP Field Sampling Planft/ft Feet per FootGC/MS Gas Chromatography/Mass SpectroscopyHDR HDR Engineering, Inc.1C Institutional ControlIRIS Integrated Risk Information System Online Databasekg/L Kilogram per LiterMCL Maximum Contaminant Limitmg/kg Milligrams per Kilogrammg/L Milligrams per LiterMNA Monitored Natural AttenuationMSL Mean Sea LevelMTBE Methyl Tertiary butyl EtherNAPL Non Aqueous Phase LiquidNAVD North American Vertical DatumNCP CERCLA National Contingency PlanNPDES National Pollutant Discharge Elimination SystemO&M Operations and MaintenancePCE TetrachloroethenePID Photoionization DetectorPOTW Publicly Owned Treatment WorksPRG Preliminary Remediation GoalQA/QC Quality Assurance/Quality ControlQAPP Quality Assurance Project Plan (HDR)RAGS Risk Assessment Guidance for SuperfundRAO Remedial Action ObjectiveRBC(s) Risk-Based Concentration(s)RCRA Resource Conservation and Recovery ActRfD Reference DoseRI Remedial Investigation



RI/FS Remedial Investigation/Feasibility StudyRME Reasonable Maximum ExposureRRU Relative Response UnitSAP Sampling and Analysis PlanSARA Superfund Amendments and Reauthorization ActSGS Soil Gas SurveySOP(s) Standard Operating Procedure(s)SOW Statement of WorkSVE Soil Vapor ExtractionTCA TrichloroethaneTCE Trichloroethenethe District South Davis Sewer Districtthe Site WS Hatch Co SiteTOC Total Organic CarbonUDEQ Utah Department of Environmental Qualityug/kg Microgram per KilogramUGS Utah Geologic SurveyUSDA United States Department of AgricultureUSEPA United States Environmental Protection AgencyUV UltravioletVC Vinyl ChlorideVOC(s) Volatile Organic Compound(s)



EXECUTIVE SUMMARY

This Focused Feasibility Study (FFS) identifies and evaluates remedial alternatives to reducepotential risk to human health and the environment associated with chlorinated solventcontamination at the W.S. Hatch Company (Hatchco) Site in Woods Cross, Utah.

Hatchco operated between 1936 and 1995 primarily as a bulk carrier of petroleum and petroleumproducts. Hatchco facilities were also used to service, clean and park tractor-trailers and tanktrucks. The property was home to approximately 75 trucks, 200 trailers and 125 employees at thepeak of operations. Facility demolition begun in 1995 was accompanied by remedial measures toaddress wastes and contaminated soils as they were encountered.

Prior investigative and remedial work includes a remedial investigation (RI), severalcontaminated soil removal/treatment/disposal projects, and the installation and operation of anin-situ groundwater remediation system. The RI consisted of a soil gas survey followed by soiland groundwater sampling and analysis for volatile organic compounds (VOCs). A baselinehuman health risk assessment estimated current and potential future risks to human health andthe environment.

An area of subsurface soils contaminated with chlorinated VOCs was identified under thelocation of some former Site structures including a truck wash facility and associated frenchdrain and oil/water separator. The sum of all VOCs detected in the most contaminated soilsample was 510 milligrams per kilogram (mg/kg). A small amount of non-aqueous phase liquidwas noted in one subsurface soil sample collected above the water table. However, the absenceof large quantities of VOCs in this interval suggested the liquid was a heavy hydrocarbon.

The water table occurs between 10 and 40 feet below the ground surface across the study area.Chlorinated VOCs were detected in groundwater samples at concentrations up to 1.3 milligramsper liter (mg/L) (sum of all VOCs). The contaminant plume was mapped approximately 1,200feet to the west-northwest of the Site boundary, following the local groundwater flow direction.Some minor plume migration also occurs to the south and southeast of the Site. In addition,VOCs were detected in a confined saturated interval at concentrations approximately 100 timeslower than in the overlying water table aquifer.

The baseline risk assessment determined that potential adverse health effects from contaminantsin surface and subsurface soils were below a level of concern. Potential adverse health effectsposed by direct ingestion of contaminated groundwater are above a level of concern both on- andoff-Site. However, there is no known current use of groundwater as a drinking water sourcewithin the mapped contaminant plume originating from the Site. However, the use ofcontaminated groundwater will not be known with certainty until EPA completes work in areassurrounding the Hatchco Site.

Prior remedial measures included:

• Removal and disposal of an oil/water separator.

• Excavation and land farming of contaminated soils/gravel associated with a french drain.

W.S. Hatch Co. ES-1 HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

• Removal and disposal of an underground storage tank and remediation of underlyingcontaminated soils.

• Installation and operation of an air sparging system with periodic introduction of anadditive to enhance natural biodegradation of Site contaminants.

The general Remedial Action Objectives (RAOs) for the Site include:

• Prevent unacceptable exposure risk to current and future human populations posed bySite contaminants.

• Restore groundwater to beneficial use (if possible).

Media-specific RAOs include:

Subsurface soils - Remediation of subsurface soils would be pursued to reduce the potential forcontaminant migration from soils to groundwater. Based on Soil Screening Guidance (TechnicalBackground Document, EPA, 1996), the default threshold concentration for TCE in soils isdriven by the potential for it to act as a source for groundwater contamination. The default valueis 60 micrograms per kilogram (ug/kg) (based on a 20-fold dilution/attenuation factor).

Groundwater - Preliminary remediation goals (PRGs) will be the maximum contaminant limits(MCLs) or risk-based concentrations based on a hazard index of one or cancer risk of 1E-4.Chemical-specific PRGs for groundwater are provided below in Table ES-1.

TABLE ES-1Chemical-Specific PRGs for Groundwater

Chemical

trichloroetheneperchloroethenevinyl chloridecis- 1 ,2-dichloroethenebenzenenaphthalene1 ,2,4-trimethylbenzene

Basis for PRG

MCLMCLMCLMCLMCLHazard Index = 1Hazard Index = 1

Preliminary Remediation Goal(ug/L)

552

705

6.5a

12a

- Residential risk-based concentration. On-Site land use is expected to be commercial/industrial.

There are no location-specific ARARs. The remedial alternatives are evaluated against thefollowing potential chemical- and action-specific ARARs:

Potential Chemical-Specific ARARs:

• National Primary and Secondary Drinking Water Standards

• Utah Primary Drinking Water Standards


ES-2 HDR Engineering, Inc.July 2004

• Utah Groundwater Quality Standards

• Utah Alternate Corrective Action Concentration Limits

• Utah Corrective Action Clean-up Standards at UST and CERCLA sites

Potential Action-Specific ARARs:

• Clean Water Act Ambient Water Quality Criteria

• National Pollutant Discharge Elimination System (NPDES)

• National Underground Injection Control Regulations

• National Guidelines Establishing Test Procedures for the Analysis of Pollutants

• Utah Well Drilling and Completion Standards

— » --Utah Small Source Exemption De-minimis Emissions

• Utah Discharges to Surface Water (UPDES)

• Utah Underground Injection Control

• Utah Fugitive Dust Control

The FFS examined a range of potentially applicable remedial technologies and identified those tobe assembled into a range of remedial alternatives. The alternatives included the No-ActionAlternative and options that rely primarily on natural attenuation mechanisms to achieve RAOs.The alternatives also included treatment of soils and extracted groundwater with contaminantphase transfer technologies as well as treatment of extracted groundwater using contaminantdestruction technologies. Soil excavation with off-Site disposal was also considered. Theremedial alternatives were screened against three evaluation criteria including: OverallEffectiveness, Overall Implementability, and Overall Cost. The alternative involving soilexcavation with off-Site disposal was rejected during the screening process. The retainedalternatives subjected to the detailed and comparative analyses included:

• Alternative 1 - No Further Action

• Alternative 2 - Monitored Natural Attenuation (MNA) w/Institutional Controls (ICs) -Perform long-term groundwater monitoring. Implement an 1C restricting on-and off-Sitegroundwater use.

• Alternative 3 - Surface Capping w/Institutional Controls - Install low-permeability coveron area of subsurface soil contamination inferred to represent the source for groundwatercontamination. Perform long-term groundwater monitoring. Implement an 1C restrictingon-and off-Site groundwater use.

• Alternative 4 - Soil Vapor Extraction w/Institutional Controls - Install a soil vaporextraction system in subsurface soil contamination inferred to represent the source forgroundwater contamination. Perform long-term groundwater monitoring. Implement an1C restricting on-and off-Site groundwater use.


• Alternative 6 - Enhanced In-Situ Bioremediation w/Institutional Controls - Periodicallyinject an additive into the aquifer to stimulate bacterial metabolism and cometabolism ofcontaminants. Perform long-term groundwater monitoring. Implement an 1C restrictingon-and off-Site groundwater use.

• Alternative la - On-Site Groundwater Extraction w/Above Ground Treatment via AirStripping w/Institutional Controls - Establish hydraulic capture of the majority of thegroundwater contaminant plume at the western Site boundary. Treat extractedgroundwater by air stripping, and discharge treated water to a storm sewer. Perform long-term groundwater monitoring. Implement an 1C restricting on-and off-Site groundwateruse.

• Alternative 7b - On-Site Groundwater Extraction w/Above Ground Treatment viaUltraviolet Oxidation w/Institutional Controls - Establish hydraulic capture of themajority of groundwater contaminant plume at the western Site boundary. Treat extractedgroundwater by UV/Oxidation and discharge treated water to a storm sewer. Performlong-term groundwater monitoring. Implement an 1C restricting on-and off-Sitegroundwater use.

• Alternative 7c - On-Site Groundwater Extraction w/Discharge to Publicly OwnedTreatment Works w/Institutional Controls - Establish hydraulic capture of the majority ofthe groundwater contaminant plume at the western Site boundary. Discharge untreatedextracted groundwater to the Publicly Owned Treatment Works. Perform long-termgroundwater monitoring. Implement an 1C restricting on-and off-Site groundwater use.

The detailed analysis evaluated each retained alternative against the nine National ContingencyPlan (NCP) criteria. The comparative analysis compared the alternatives to each other using theevaluation criteria as a measure.

The NCP criteria include:

• Overall Protection of Human Health and the Environment

• Compliance with ARARs

• Long-Term Effectiveness and Permanence

• Reduction in Toxicity, Mobility and Volume Through Treatment

• Short-Term Effectiveness

• Implementability

• Cost

• State Acceptance

• Community Acceptance

A summary of the comparative analysis of the alternatives is presented in Table ES-2.


TABLE ES-2Comparative Analysis Using NCP Criteria

Evaluation Criteria Alternative 1 - No ActionAlternative 2 - Monitored NaturalAttenuation (MNA) w/Institutional

Controls

Alternative 3 - Surface Cappingw/Institutional Controls

Alternative 4 - Soil VaporExtraction w/Institutional Controls

Alternative 6 - Enhanced In-SituBiological/Chemical Remediation

w/Institutional Controls

Alternative 7a - Treatment via AirStripping w/Institutional Controls

Alternative 7b -Treatment via

Ultraviolet Oxidationw/Institutional Controls

Alternative 7c -Discharge to POTW


EffectivenessDverall Protection of Humaniealth and Environment

Improvements in groundwater andvadose zone soil conditionsachieved through naturalattenuation. However, lack of 1Cmay result in health risk above alevel of concern. Permanentcompliance with MCLs in off-Siteareas is predicted to occurbetween 2022 and 2057.

Achieves improvements in groundwaterand vadose zone soil conditions in thesame time frame as Alternative 1.Implementation of 1C will minimizepotential for human health risk above alevel of concern. Permanentcompliance with MCLs in off-Siteareas is predicted to occur between2022 and 2057.

Achieves improvements ingroundwater conditions more quicklythan under Alternatives 1 and 2 bylimiting migration of COCs togroundwater. Vadose zone soils willreach RAOs in similar or longer timeframe than under Alternatives 1 and 2due to reduced infiltration andassociated leaching of contaminants.Implementation of 1C will minimizepotential for human health risk above alevel of concern. Some reduction inamount of time needed to achievepermanent compliance with MCLs ascompared with Alternatives 1 and 2 inoff-Site areas may be achieved.

Achieves improvements ingroundwater and vadose zone soilconditions more quickly than underAlternatives 1-3 by removing COCsfrom the inferred source area.Implementation of 1C will minimizepotential for human health risk above alevel of concern. Some reduction in theamount of time needed to achievepermanent compliance with MCLs ascompared with Alternatives 1 and 2 in

the off-Site areas may be achieved.

Achieves improvements ingroundwater more quickly thanunder Alternatives 1 -4 throughenhanced in-situ destruction ofCOCs. Implementation of 1C willminimize potential for human healthrisk above a level of concern. Somereduction in the amount of timeneeded to achieve permanentcompliance widi MCLs as comparedwith Alternatives 1 and 2 in off-Siteareas may be achieved.

Achieves improvements in off-Sitegroundwater more quickly than underAlternatives 1-4 (and possibly 6) throughextraction of contaminated groundwater.Improvements in vadose zone soilswould occur at the same rate as underAlternatives 1-3. Implementation of 1Cwill minimize potential for human healthrisk above a level of concern.Compliance with MCLs in off-Site areasis predicted to occur in 2017. However,permanent reduction in COCs in off-Site areas may require continuedoperation of this alternative beyond2017 to prevent off-Site migration of

'OCs remaining on-Site aboveMCLs.

See Alternative 7a See Alternative 7a.

Compliance with RemedialAction Objectives and

Achieves RAOs and complieswith chemical-specific ARARsthrough natural attenuation. Nolocation-specific ARARs.

Achieves RAOs in the same time frameas Alternative 1. Complies withchemical- and action-specific ARARs.No location-specific ARARs.

Achieves RAOs in a shorter timeframe than under Alternatives 1 and 2.Complies with chemical- and action-specific ARARs. No location-specificARARs.

Achieves RAOs in a shorter time framethan under Alternatives 1-3. Complieswith chemical- and action-specificARARs. No location-specific ARARs.

Achieves RAOs in a shorter timeframe than under Alternatives 1-4.Complies with chemical- and action-specific ARARs. No location-specific ARARs.

Achieves RAOs in a shorter time framethan under Alternatives 1-4. Complieswith chemical- and action-specificARARs. No location-specific ARARs

See Alternative 7a. See Alternative 7a.

Long-Term Effectiveness Permanence is achieved throughnatural attenuation. Some risksassociated with groundwater useaefore RAOs are met.

Protection achieved at the time of 1Cimplementation. Reliability of 1Cdepends on effectiveness ofenforcement agency. Permanenceachieved through natural attenuation.

Protection achieved at the time of 1Cmplementation. Reliability of 1Cdepends on effectiveness ofenforcement agency. Permanenceachieved through natural attenuation.Degree of effectiveness in acceleratingachievement of groundwater RAOs isunknown.

Protection achieved at the time of 1Cmplementation. Reliability of 1C

depends on effectiveness ofenforcement agency. Permanenceachieved through natural attenuation.Operation of remediation system will>e required for at least several years.Effectiveness (contaminant massrecovery) may be limited by Sitecharacteristics.

Protection achieved at the time of 1Cimplementation. Reliability of 1Cdepends on effectiveness ofenforcement agency. Permanenceachieved through enhanced naturalattenuation. Multiple application ofchemical additive would be required.Effectiveness (degree ofenhancement of COCbiodegradation) may be limited bySite characteristics.

Protection achieved at the time of 1Cimplementation. Reliability of 1Cdepends on effectiveness of enforcementagency. Permanence achieved throughextraction of contaminated groundwaterand natural attenuation of COCs invadose zone soils.


Reduction of Toxicity,[Mobility and Volume

deduction in mobility, toxicityand volume through naturalattenuation.

deduction in mobility, toxicity andvolume is the same as for Alternative 1.

deduction in toxicity and volume is thesame as for Alternative 1. Contaminantmobility is lowered through reductionin infiltrating water.

Contaminant mobility increasedhrough the discharge of extracted soilvapor. Potentially higher mobility thanall other Alternatives. Reduction incontaminant toxicity and volumeroughly similar to alternatives 1-3.

Reduction in mobility, toxicity andvolume greater than underAlternatives 1-4 through COCdestruction.

Contaminant mobility increased throughair stripper discharge. Reduction incontaminant toxicity and volume roughly potimilar to alternatives 1-4.

Reduction in mobility,toxicity and volume

:entially greater thanunder Alternatives l-7athrough destruction ofCOCs by UV Oxidation.

See Alternative 7b.



TABLE ES-2Comparative Analysis Using NCP Criteria


Controls


Alternative 4 - Soil VaporExtraction w/Institutional Controls



Alternative 7a - Treatment via AirStripping w/Institutional Controls

Alternative To -Treatment via

Ultraviolet Oxidationw/Institutional Controls



ImplementabilityShort Term Effectiveness

Technical Feasibility

Administrative Feasibility

>Availability of Services andMaterials

Anticipated State Acceptance

Anticipated CommunityAcceptance

Involves no further remedialaction.

No Action Required.

No Action Required.

No Action Required.

Assessed during FFS commentDeriod.

Assessed during FFS commentperiod.

No short-term risks as associated withthis alternative.

No technical issues are associated withthis alternative.

The willingness of the municipality toadminister the 1C has not beenevaluated. An agreement would have tobe reached with the City of WoodsCross to enforce a groundwater userestrictions.

Services and materials are readilyavailable.

Assessed during FFS comment period.


Short term risks are similar to thoseunder Alternatives 1 and 2.

All required technologies are readilyavailable.

See Alternative 2.

See Alternative 2.



Short term risks are similar to thoseunder Alternatives 1 and 2. Risksassociated with vapor intrusion intofuture on-Site structures may bereduced through operation of a SVEsystem. Risks associated withdischarge of soil vapor expected to benegligible.All required technologies are readilyavailable.

See Alternative 2.

See Alternative 2.





See Alternative 2.

See Alternative 2.

Assessed during FFS commentDeriod.


Short term risks are similar to thoseunder Alternatives 1 and 2. Risksassociated with discharge of soil vaporexpected to be negligible.

Groundwater modeling indicates it maynot be possible to establish hydrauliccapture of entire plume along westernSite boundary w/out adversely affectingoverlapping petroleum plume to thenorth.

See Alternative 2.

See Alternative 2.



See Alternative 7a.

See Alternative 7a.

See Alternative 2.

See Alternative 2.

Assessed during FFScomment period.


See Alternative 7a.

See Alternative 7a.

The POTW will not acceptuntreated discharge. Notimplementable.

See Alternative 2.

Assessed during hhScomment period.


Cost

Capital Costs

Present Value O&M Costs

Periodic Costs

Present Value

$0

$0

$0

$9,531

$58,167

$0

$67,698

$89,040

$58,167

$0

$147,207

$53,945

$92,942

$11,435

$158,322

$149,848

$42,694

$136,258

$328,800

$70,687

$260,261

$4,461

$335,409

$224,197

$397,052

$4,460

$625,709

$49,109

$152,986

$4,461

$206,556



1.0 INTRODUCTION

1.1 Purpose and Scope of the Focused Feasibility Study

HDR Engineering, Inc. (HDR) has prepared this Focused Feasibility Study (FFS) Report forW.S. Hatch Company (Hatchco). The FFS was completed in accordance with the AdministrativeOrder on Consent (AOC) for RI/FS, EPA Docket #CERCLA-8-2001-14. As established in theConsent Order, the technical objectives of the United States Environmental Protection Agency(EPA) and Hatchco consist of the following:

• To determine the nature and extent of contamination and any threat to public health,welfare, or the environment caused by the release or threatened release of hazardoussubstances, pollutants or contaminants at or from the Hatchco Property (Site) byconducting a remedial investigation (RI).

- •- To determine and evaluate alternatives for remedial action (if any) .to prevent, mitigate, orotherwise respond to or remedy any release or threatened release of hazardoussubstances, pollutants, or contaminants at or from the Site, by conducting a feasibilitystudy.

Since 1995, the Site has undergone considerable investigative and remedial measures prior to theinitiation of the FFS. As a result, the FFS focuses on answering specific questions not alreadyaddressed through prior work. The purpose of the FFS is to evaluate a "short-list" of remedialalternatives proven to be effective for source removal/mitigation and prevention of off-Sitemigration of contaminated groundwater. Monitored natural attenuation is also considered alongwith the No-Action Alternative. The focused nature of the FFS is described in the FinalStatement of Work (SOW) included in the AOC. The AOC was signed by the Director of theSuperfund Remedial Response Program on September 28, 2001.

1.2 Report Organization

This FFS Report is organized to include the elements suggested in the CERCLA Guidance(EPA/540/G-89/004). The specific report organization is as follows:

Executive Summary

1.0 Introduction2.0 Summary of Remedial Investigation3.0 Summary of Previous Remedial Measures4.0 Remedial Action Objectives5.0 Applicable, Relevant or Appropriate Requirements6.0 Screening of Remedial Technologies7.0 Screening of Remedial Alternatives8.0 Detailed Analysis of Alternatives9.0 Comparative Analysis10.0 References

W.S. Hatch Co. 1-1 HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

FiguresAppendices

1.3 Site Location

The Site occupies approximately 3 acres between Interstate 15 (1-15) and 800 West Street, andlies just south of 500 South Street in Woods Cross, Davis County, Utah (Figure 1-1). The Siteand surrounding area is shown on Figure 1-2. The Site is found in Section 25, Township 2N,Range 1W of the Salt Lake Base Line and Meridian. The street address is 643 South 800 Westand the Site's geographic coordinates are 40°52'57" north latitude and 111°54'02" westlongitude.

Hatchco initially operated on 13 acres of which 10 are now owned by Kalahari Properties, L.L^C.(Kalahari). Properties adjacent to the Site include a Phillips 66 petroleum trucking terminal to thenorth, and roadways to the east, west and south. The Site slopes gently to the west atapproximately 0.025 feet per foot(ft/ft)-ancHies at an elevation of 4,300-feet above mean sealevel.

1.4 Ownership and Site Operations

Willard S. Hatch started the W.S. Hatch Co. in 1936 after purchasing an asphalt distributor truck.Over time, Hatchco's business operations specialized in serving as a bulk carrier of petroleumand petroleum products including diesel, gasoline, petroleum solvents (such as toluene andxylene), and asphalt. Hatchco also carried other products including fruit, dirt, and sand.

Hatchco facilities were also used to service, clean, and park tractor-trailers and tank trucks. A1986 Hatchco publication indicated that Hatchco carried a wide range of products, including"liquid and dry waste materials" and nitrogen tetroxide, an oxidizer used in missile propulsion.Hatchco was home to approximately 75 trucks, 200 trailers, and approximately 125 employees atthe peak of its operations. Figure 1-3 provides a Site plan illustrating historic features.

Hatch Service Company, a wholly owned subsidiary of Hatchco, also operated at this locationand was a specialized carrier of constituents of explosives. Hatch Service Company trucksreportedly carried ammonium nitrate, fuel oil, and high-energy fuel, which were mixed by thetruck and used as explosives at mining operations. Hatch Service Company ceased operations inthe late 1980s and was involuntarily dissolved on December 1, 1998.

Jack B. Kelley, Inc., a Texas corporation, purchased all of Hatchco's stock on December 10,1986. In 1995, business operations ceased on the original 13 acres and Hatchco began removingstructures to prepare a portion of the property to be sold to Kalahari. Hatchco conveyed theapproximate ten-acre portion of the property to Kalahari through a warranty deed datedDecember 30, 1997. Hatchco still retains title to approximately three acres of the original 13acres, and this real property represents Hatchco's only significant asset.


2.0 SUMMARY OF REMEDIAL INVESTIGATION

2.1 Geology and Hydrogeology

2.1.1 Geology

Figure 2-1 shows the location of a geologic cross-section presented in Figure 2-2. The cross-section of the Study Area is based on data collected from soil borings.

Much of the north and east portions of the Site are covered with a gravel driveway. Surface soilsin non-driving areas consist of dark brown to black sandy, gravelly clay. Native soils beginapproximately 4 to 8-feet below ground surface (bgs) (Figure 2-2). Native subsurface soils areprimarily medium-stiff to stiff, medium to highly plastic clays to approximately 17-feet bgs.Below the clays are layers of dense, well-graded sand and gravel which alternate with layers ofsandy, silty clay. Water is typically encountered in sand and gravel zones at 24-30-feet bgs. Aclayaquiclude'exists on-Site at approximately 36-feet bgs. This low-permeability layer extends -to 55-feet bgs in the boring used to install deep monitoring well MW-3D, below which there areclays alternating with minor (1 to 3-foot) layers of sand to 80-feet bgs. Below the clay at 80-feetbgs is sand and gravel. This sand and gravel extends to 91-feet bgs in the MW-3D boring,terminating at a clay base (Figure 2-2).

In off-Site borings, approximately ten feet of native clay lies below fill and extends to 14-feetbgs. Below the clay is saturated sand and gravel. The vertical extent of the sand and gravel is notwell known off-Site because downgradient borings were completed only a few feet below thedepth that water was encountered. However, boring MW-12S was advanced 3-feet into dry-to-moist clay beginning at 24-feet bgs. This clay could be interpreted to be the same aquicludeencountered in the on-Site borings.

2.1.2 Hydrogeology

In the Site vicinity, two saturated intervals are considered relevant. On the Hatchco property, ashallow unconfined aquifer is first encountered at depths ranging from about 24- to 30-feet bgs,with a deeper confined aquifer first encountered at about 80-feet bgs. A clay aquiclude firstencountered at 36-feet bgs and extending to 80-feet bgs separates the shallow and deep aquifers.The shallow aquifer is approximately 10-feet thick, and is comprised of unconsolidated, coarse-grained alluvial sediments. The deep aquifer extends to an undetermined depth, although claywas encountered at 91-feet bgs in both deep borings (MW-1D and 3D).

Downgradient of the Site, groundwater is encountered at shallower depths due to groundelevations dropping to the west. Groundwater can be seen at depths as shallow as 6.5-feet bgs(MW-14S). Wells were installed in the unconfined aquifer just below depths where saturatedconditions were first encountered. For this reason, the deepest off-Site well installed extends to30-feet bgs (MW-1 IS).

The deeper confined aquifer may be representative of the western-coalesced multiple aquifersystem present at the base of the mountains. The shallow unconfined aquifer is considered bysome researchers to be part of the overall groundwater system, but not necessarily a part of the


overall East Shore aquifer system. This is because the aquifer has no clear connection to rechargeareas further east, and little is known about recharge to this aquifer zone from precipitation,seepage from irrigation, and urban runoff (Clark et. al. 1990). A similar lack of data existsconcerning discharge from this aquifer zone.

2.1.3 Horizontal Hydraulic Gradient

Water level elevations obtained from shallow monitoring wells installed during the RI arepresented in Table 2-1. The potentiometric surface of the unconfined aquifer indicates thedominant groundwater flow is to the west-northwest (Figure 2-3). However, a southerly flowcomponent is inferred to exist south of the Site. The magnitude of the horizontal groundwatergradient to the west-northwest across the shallow monitoring well network has been calculated toaverage 0.003 ft/ft over four quarters of data. The magnitude of the horizontal gradient is greater(0.005 ft/ft) to the west of MW-10S. East of MW-10S (including the Site) the gradient is moreflat, at 0.001 ft/ft. An average hydraulic gradient of 0.005 ft/ft is estimated for the southerly flowcomponent. "" "' "

The southern component of groundwater flow is counter to the regional gradient and appears tobe due to a high in the water table at the Site. The reason for the high is not known. The Site ison a slight topographic high with the land sloping to the south and the west. This naturaltopography may be responsible for the shape of the water table. All local surface water featuressuch as Mill Creek and a related detention basin are concrete lined, minimizing.the likelihood ofconcentrated recharge at these locations potentially affecting local hydrogeology.

2.1.4 Vertical Hydraulic Gradient

Vertical gradient information was obtained through the installation of monitoring well clusters inboth shallow (unconfined) and deep (confined) aquifers. Two well clusters have been installed:upgradient cluster MW-1S and ID, and on-Site cluster MW-3S and 3D. The magnitude of thevertical gradient is found by measuring the difference in head between the two wells, anddividing by the vertical distance from the bottom of the shallow well screen to the top of the deepwell screen. A positive (downward) gradient of approximately 0.12 ft/ft has been calculated forthe two well clusters. It should be noted that drought conditions existed at the time of the RI andthe measured vertical hydraulic gradient may not be representative of typical conditions. Table 2-2 shows water level elevations in the two well clusters, and presents the calculated verticalgradient.

2.1.5 Slug Testing

Certain monitoring wells were selected for slug testing in order to estimate hydraulicconductivity for use in contaminant transport modeling. The slug tests were completed after anevaluation of the most suitable (e.g., representative) monitoring wells for slug testing was made.Three wells (MW-2S, MW-3S, and MW-12S) were chosen for slug testing. Wells MW-2S andMW-3S are located on-Site, and MW-12S is off-Site and downgradient. Slug testing wasperformed on November 8, 2002. The resulting K (hydraulic conductivity) values are presentedon Table 2-3.

W.S. Hatch Co.. 2-2 HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

TABLE 2-1Water Level Data - Unconfined Aquifer

Date:

TOCWell Elev.

MW-1S 4306.00MW-1D 4305.99MW-2S 4304.95MW-3S 4299.97MW-4S 4299.07MW-5S 4293.84MW-6S 4289.45MW-7S 4285.24MW-8S 4293.12PZ-2 4305.12

3/22/2002Depth to WaterWater Elevation

(Ft BTOC) (Ft. MSL)33.82 4272.1837.01 4268.98

31.45 4273.67


(Ft. BTOC) (Ft. MSL)33.52 4272.48

31.39 4273.5626.57 4273.4025.64 4273.43

31.23 4273.89

5/14/2002Depth to Water

Water Elevation(Ft. BTOC) (Ft. MSL)

29.52 4275.4324.50 4275.4723.73 4275.3417.82 4276.0213.79 4275.6612.67 4272.5717.25 4275.8729.67 4275.45

5/16/2002 ;Depth to WaterWater Elevation

(Ft. BTOC) (Ft. MSL)31.25 4274.75

29.57 4275.3824.61 4275.3623.85 4275.2218.05 4275.7914.01 4275.4412.79 4272.4517.36 4275.7629.68 4275.44


(Ft. BTOC) (Ft MSL)31.24 4274.76

29.60 4275.3523.91 4276.0624.40 4274.6718.02 4275.8214.24 4275.2112.93 4272.3117.51 4275.6129.66 4275.46


(Ft. BTOC) (Ft. MSL)31.40 4274.60

29.88 4275.0725.09 4274.8824.26 4274.8118.77 4275.0714.86 4274.5913.26 4271.9818.05 4275.0729.82 4275.30

Date:

TOCWell Elev.

MW-1S 4306.00MW-1D 4305.99MW-2S 4304.95MW-3S 4299.97MW-3D 4298.76MW-4S 4299.07MW-5S 4293.84MW-6S 4289.45MW-7S 4285.24MW-8S 4293.12MW-9S 4287.57MW-10S 4287.86MW-11S 4288.10MW-12S 4280.34MW-13S 4277.99MW-14S 4272.69PZ-2 4305.12


(Ft. BTOC) (FL MSL)31.87 4274.1339.47 4266.5230.22 4274.7325.41 4274.56

24.56 4274.5119.16 4274.6815.36 4274.0913.58 4271.6618.41 4274.71

30.10 4275.02


(Ft. BTOC) (Ft MSL)34.21 4271.7942.77 4263.2231.53 4273.4226.74 4273.23

25.98 4273.0920.44 4273.4016.72 4272.7314.36 4270.8819.72 4273.4015.07 4272.5015.43 4272.4315.68 4272.42

31.31 4273.81


(Ft BTOC) (Ft. MSL)34.89 4271.1139.50 4266.4932.12 4272.8327.48 4272.4932.84 4265.9226.62 4272.4521.40 4272.4417.64 4271.8115.22 4270.0220.68 4272.4415.68 4271.8916.08 4271.7816.41 4271.6910.06 4270.289.07 4268.926.40 4266.2931.91 4273.21


(Ft BTOC) (Ft MSL)34.92 4271.0837.22 4268.7733.12 4271.8328.63 4271.3431.66 4267.1028.03 4271.04

i

21.94 4271.1817.33 4270.2417.16 4270.7017.72 4270.3810.80 4269.549.62 4268.377.14 4265.55


(Ft. BTOC) (Ft. MSL)35.20 4270.8037.35 4268.6433.48 4271.4728.66 4271.3131.81 4266.9527.76 4271.3122.23 4271.6118.13 4271.3216.14 4269.1021.50 4271.6216.52 4271.0516.88 4270.9817.60 4270.5010.10 4270.248.76 4269.235.70 4266.99


(Ft BTOC) (Ft MSL)35.27 4270.7337.44 4268.5533.58 4271.3728.78 4271.1931.99 4266.7727.88 4271.1922.30 4271.5418.23 4271.2216.21 4269.0321.61 4271.5116.63 4270.9416.95 4270.9117.66 4270.4410.17 4270.178.84 4269.155.86 4266.83

'TOC-Top of Casing1 BTOC - Below Top of Casing

W.S. Hatch Co.Focused Feasibility Final Report

2-3 HDR Engineering, Inc.July 2004

TABLE 2-2Vertical Gradient Calculation - October 2002

Well ID

MW-1SMW-1DMW-3SMW-3D

Top ofScreen

Elevation(Ft. MSL)4282.504226.994274.474220.59

Bottom ofScreen

Elevation(Ft MSL)4262.504216.994264.474210.59

Bottom ofShallow -Top

of Deep(Ft)

35.51

43.88

Head(Groundwater

Elevation)(Ft. MSL)

4271.114266.494272.494267.25

Difference inHead(Ft)

4.62

5.24

VerticalGradient

0.13 feet/foot

0.1 2 feet/foot

TABLE 2-3Slug Test Results

Well ID

MW-2SMW-3S

MW-12S

K(ft/day)

1.4682.7

K(cm/sec)4.9 x 10"2.4 x 10-1

9.6 x 10"

Published Lithologyfor K Value

Silty sandClean sand

Silty sand to clean sand

The higher hydraulic conductivity value at MW-3S is due to the presence of coarser materialthan the other wells. The published lithologies for the software-derived K values generally agreewith the type of sediment each well is screened in.

2.2 Nature and Extent of Contamination

2.2.1 Surface Soils

Thirteen surface soil (2 to 6 inches bgs) samples (SS-001 through SS-013) were collected fromthe Site and analyzed for volatile organic compounds (VOCs). Low concentrations of VOCs(benzene, cis-l,2-dichloroethene [cis-l,2-DCE], tetrachloroethene [PCE], toluene, andtrichloroethene [TCE]) were detected in three of the samples. Concentrations of compoundsdetected in soil samples are shown on Figure 2-4.

2.2.2 Soil Gas Survey (SGS) Results

Over 200 soil gas samples were collected on and around the Site. On-Site detections for soil gassample depths of 5-feet, 15-feet and 25-feet are summarized on Figures 2-5 through 2-7. Figure2-8 summarizes soil gas detections in the off-Site areas sampled.

As shown in Figures 2-5 through 2-7, SGS results identified potential "hot-spots" in the on-Siteareas of sampling locations 82, 140 and 207. As discussed in Sections 2.2.3 and 2.2.4, theseareas were further investigated with Geoprobe® soil borings and groundwater samples, andinstallation and sampling of groundwater monitoring wells.



No significant detections were found in the off-Site, triangular-shaped, City of Woods Crossproperty west of 800 West Street (sampling locations 172 through 202, see Figure 2-8).Increasing concentrations of benzene were detected in over half of the samples collected along800 West Street.

2.2.3 Subsurface Soils

Fifteen subsurface soil samples were collected from eight borings (DPS-018, DPS-041, DPS-064, DPS-082, DPS-104, DPS-140, DPS-171, and DPS-207) at depths ranging from 7- to 35-feetbgs. Analytical results from the off-Site laboratory are shown on Figure 2-9.

Soil samples from the saturated zone were also collected for total organic carbon (TOC) analysisand clay speciation. Samples were collected from MW-2S, MW-3S, MW-4S, MW-10S, andMW-1 IS from the zones in which monitoring well screens were installed. The purpose of thissampling was to collect data to be used in evaluating the potential for retardation and attenuationof chlorinated solvents. Total organic carbon data are summarized in Table 2-4. Clay speciationreports are provided in Appendix I of the RI Report.

TABLE 2-4Total Organic Carbon Analysis

MonitoringWell Location

MW-2SMW-3SMW-4S

MW-1 OSMW-1 IS

Screened Interval(Ft. bgs)

34-4923-3323-3310-2010-30

Sample Depth(Ft bgs)

4232291729

Result(mg/kg)

1356391189220

2.2.4 Groundwater

Groundwater samples were collected and analyzed for VOCs from six on-Site Geoprobe®locations, four on-Site monitoring wells (three shallow wells and one deep well), and nine off-Site monitoring wells (eight shallow wells and one deep well).

All of the Geoprobe® samples had detectable concentrations of various VOCs (Figure 2-10).Various VOCs were also detected in each of the four on-Site wells with TCE and cis-l,2-DCEbeing detected in each well (Figure 2-11). Detectable concentrations of VOCs were found in allsampled off-Site wells except MW-8S.

Figure 2-12 provides an isoconcentration contour map of chlorinated VOCs in shallowgroundwater based on data collected during the first round of quarterly groundwater sampling.Figure 2-13 summarizes available groundwater chemistry data collected during the RI as well asoff-Site data collected by the EPA and Utah Department of Environmental Quality (UDEQ)between 1997 and 2002.



2.2.5 Origin and Extent of Soil Contamination

Surface soil chemical data are presented on Figure 2-4. A review of this figure reveals levels ofVOCs below or near detection limits. This is not unexpected given the volatile nature of Sitecontaminants and the fact the Site has been inactive for over eight years. The significance ofthese detections with respect to human health risks is discussed in Section 2.4.

The RI employed screening quality analytical information in the form of soil gas data to focusthe subsurface soil and groundwater investigation on those areas of the Site with the highestrelative contaminant concentrations. The results of over 200 shallow soil gas samples were usedto locate suspected contaminant release points. Additional soil gas samples collected at depthwere used to verify the horizontal location of the release points by identifying a vertical columnof contaminated soil gas between the surface and the water table. A review of Figures 2-5through 2-7 shows two areas with this characteristic. The most significant of these is centeredabout soil gas sample station 82 and is the location of the former wash rack. The second is lesssignificant and is"centered abouTsoil gas station 140."No historic structures are associated withthis location. These two locations represent suspected contaminant release points.

In addition to the two locations displaying a vertical column of contaminated soils gas, samplingstation 207 was the location of the most contaminated shallow (5-foot) soil gas sample. Nohistoric structures are associated with this location.

Soil borings were co-located with soil gas stations 82 and 140 to investigate these suspectedcontaminant release points. Additional soil borings were co-located with other soil gas stations asdiscussed below:

1. Station 207 - The highest shallow (5-foot) soil gas result was found at this location.

2. Stations 104 and 64 - These locations were considered to be hydraulically downgradientof the contaminant release locations.

3. Station 41 - This location was considered to be hydraulically upgradient of thecontaminant release points.

4. Stations 18 and 171- These locations represented Site boundary conditions.

The use of field instruments, visual criteria and odor allowed further refinement of the process bywhich soil samples were selected for laboratory analyses. By examining the continuous coreretrieved from each boring it was possible to identify the samples with the highest level ofVOCs. Analytical results for the subsurface soils samples are illustrated on Figure 2-9. A reviewof this figure and soil boring logs presented in the RI report shows the majority of subsurface soilcontamination exists in a layer that varies from one to three feet in thickness at a depth ofapproximately 20-feet. The layer occurs in the area of station 64, 207 (at 9-feet depth) and 82suggesting a release in the vicinity of stations 207 and 82 with some downgradient migration tostation 64. The lack of a release at station 64 is inferred from the lack of shallow soil gasdetections at this location (Figures 2-5 to 2-7).

The occurrence of the highest levels of subsurface soil contamination at a depth of 20-feet hastwo possible explanations. Given the current depth to water is in excess of 25-feet in the vicinity


of stations 82 and 64, the 20-foot deep contaminated layer may represent a "smear zone"emplaced when the water table was at an historically high elevation. Such a smear zone impliesan historic layer of light non-aqueous phase liquid (LNAPL) that no longer exists. The LNAPLmay have consisted of petroleum (such as diesel) with a small amount of dissolved TCE and/orPCE. Alternatively, contaminants released at the surface may have migrated vertically andponded or sorbed onto relatively low permeability layers observed at some locations associatedwith the contaminated interval at 20-foot depth.

Although contamination associated with the layer at 20-foot depth is the highest on-Site, themaximum concentration is not particularly significant. The sum of all the VOCs in the mostcontaminated soil sample (DPS-064-020, Figure 2-9) is 510 milligram per kilogram (mg/kg). Ofthe chemicals detected in this sample, only TCE is considered to be a contaminant of concern(COC) in groundwater or soil (see Section 2.4.1) occurring at a concentration of 2.8 mg/kg. The20-foot sample from station 82 (DPS-082-020) contains the highest concentration of COCs. Thesum of the COCs in this sample is 140 mg/kg (Figure 2-9). For comparison purposes, the soilsaturation limit for TCE in soil using the conservative assumptions stated below is 227 mg/kg asfollows (EPA 1996a):

Pb

c =sal /-1100mg*^-* (0.00022)1 ^^ I) ^-1+ 0.197+ (0.421)(0.188)L 1.63kg \ kg ){ L )

c = 221mskg

where:5 = Solubility in water (1100 milligram per liter [mg/L])pb = Dry soil bulk density (1.63 kilogram per liter [kg/L])

Kd = Soil-water partition coefficient (Koc x/oc)Koc = Soil organic carbon/water partition coefficient (166 L/kg)foc = fraction organic carbon in soil (0.00022)6w = water-filled soil porosity (0.197)H'= Henry's law constant (0.421)da = air-filled soil porosity (0.188)

Roughly equivalent values are obtained for other COCs. Although some oily material was notedin this sample, the amount of COCs is roughly one-half of the soil saturation limit. This suggestsnon-aqueous phase chlorinated solvents are not present at the Site. The significance of thesedetections with respect to human health risks is discussed in Section 2.4.


2.2.6 Horizontal Extent of Groundwater Impacts

A plume of groundwater impacted by VOCs released on the Site is inferred to exist on-Siteextending off-Site to the west-northwest and to the south. This is clearly illustrated on theOctober 2002 isoconcentration contour map presented as Figure 2-12. This map contours thesum of all chlorinated ethanes and ethenes detected at any given monitoring well. Similarcontours are obtained using data from the three subsequent monitoring events.

Figure 2-13 presents the concentration of the dominant chemical species at each samplingstation, including groundwater grab samples collected with direct push equipment and chemicaldata developed by EPA since 1997. Widespread groundwater contamination is illustrated on thisfigure. However, careful examination of this figure and Figure 2-12 reveals evidence of multipleoverlapping plumes originating from off-Site locations. This is discussed in detail in Section2.2.9.

The on-Site groundwater grab samples collected at stations 64 and 207 and monitoring wellMW-2S were located based on soil gas and subsurface soil chemical results indicating proximityto contaminant release point(s). As a result, the concentrations of contaminants in groundwater atthese locations are the highest measured during the RI (Figure 2-13). The parent chemicals PCEand TCE as well as their decay products dichloroethene (DCE) and vinyl chloride (VC) arepresent in the source area.

The plume migrates with the hydraulic gradient from the inferred source area to the west-northwest in a narrow band between monitoring wells 4S and 8S (Figure 2-12). Contaminantconcentrations in samples from both of these wells were near or below detection limits.Monitoring well 3S at the western Site boundary is located along the axis of the plume withcontaminant concentrations somewhat lower than those observed at the inferred release point.

Farther to the west, the plume is defined by three wells aligned roughly perpendicular to thegroundwater flow direction (9S through US). These wells provide approximate limits on thewidth of the plume at a distance of 500 feet from the inferred release point. Well 10S is in theaxis of the plume with contaminant concentrations noticeably lower than at the propertyboundary. In particular, the concentration of the parent compound TCE is lower by a factor oftwo to six relative to concentrations in MW-3S. Well 9S defines the southern limit of the plumeand well 1 IS is inferred to lie close to the northern limit of the plume. The presence of methyltertiary butyl ether (MTBE) in well 1 IS is related to an overlapping plume originating off-Site(Figure 2-13). This and other overlapping plumes are discussed in Section 2.2.9.

Farther to the west, data collected from a pair of wells (12S and 13S) suggests the continuedattenuation of the contaminant plume (Figures 2-12 and 2-13). Contaminant concentrations inthese wells are comparable and are lower by about a factor of two as compared with those foundin well 10S.

An additional well (14S) was installed to the west of well 13S. The contaminant concentrationsin this well were expected to approach detection limits. However, a marked increase incontaminant concentrations was noted at this location (Figure 2-13). The increase has beenattributed to a new source in the vicinity of well 14S. This is discussed further in Section 2.2.9.


Concentration versus time plots are provided as Figures 2-14 through 2-19 for wells MW-2S,MW-3S, MW-10S, MW-12S, MW-13S and MW-14S. These figures show relatively stableconcentration trends over the four quarters of monitoring. Stable concentrations are expectedgiven a continuous source and the short monitoring duration. A longer monitoring period wouldbe necessary to identify valid concentration trends at the Site.

One well (IS) was installed southeast of the Site to establish background water qualityconditions (Figure 2-12). Although the local hydraulic gradient is to the west-northwest, somelocalized radial flow has been inferred to exist in the vicinity of the Site (Figure 2-3). Thus, wellIS appears to be down gradient rather than upgradient of the Site. This radial flow may accountfor the low-level detection of Site contaminants in this well.

Historical groundwater quality data collected by EPA and others prior to initiation of the RI werereviewed to determine if relevant groundwater quality data exists to the south or southeast of theSite to further define the nature and extent of contamination in that area.

Three groundwater sample locations were identified in reports prepared by Lockheed Martin(2000) and PSI (1998). These data are presented on Figure 2-13 and used to develop theisoconcentration contours south and east of the Site on Figure 2-12. Based on the water tablecontours illustrated on Figure 2-3, historic groundwater monitoring station MW-5 (PSI, 1998) isdirectly south of the inferred contaminant release location associated with soil boring locationDPS-82. Contaminants of concern were not detected at this location. Historic groundwatermonitoring station MW-4 (Lockheed Martin, 2000) is located in the vicinity of Hatchco wellMW-1S. The 1996 data shows similar contaminant concentrations between MW-4 in 1996 (PCE= 38 ug/L; TCE = ND) and MW-1S in 2002 (PCE = 46 ug/L; TCE = 1 ug/L), suggesting thathistoric data in the area of the southern plume are relevant for use in characterization of thesouthern plume.

Non-detectable contaminant concentrations at historic groundwater monitoring station MW-7(PSI, 1998; Figure 2-13) further brackets the extent of contamination associated with RImonitoring well MW-1S. The low-level PCE concentration detected in the sample from MW-1Sis either part of a very narrow plume extending to the southeast of the Site or is originating froman off-Site source. Several lines of evidence suggest an as yet unidentified off-Site source maybe responsible for contamination in the vicinity of well IS. These include:

1. Tetrachloroethene occurs at a concentration of 45.8 ug/L in well IS and occurs with onlytrace levels (approx. 1 ug/L) of TCE. The PCE concentrations in well IS are higher by afactor of three compared to PCE concentrations detected on-Site and the TCEconcentrations are lower by a factor of 10 or more. Additionally, the other common Site-related chemicals (1,1-dichloroethane [1,1-DCA], cis-l,2-DCE, trans-1,2-dichloroethene[trans-1,2-DCE], and VC) are absent, suggesting a unique source for the contamination atthis location.

2. The inferred water table contours illustrated on Figure 2-3 are not consistent withgroundwater flow from the Site to well MW-1S. Hatchco acknowledges some flexibilityexists to redraw these contours given the available data.


3. A review of soil gas chemical data does not support an on-Site source dominated by PCE.Tetrachloroethene comprised less than 2% of the total VOCs detected in any of the morethan 250 soil gas samples.

2.2.7 Vertical Extent of Groundwater Impacts

Two water bearing units were identified on-Site within the first 100-feet of geologic materials.The deeper saturated zone generally occurs at a depth of 80-feet and underlies a clay layer (seeSection 2.1.2 for a discussion of Site hydrogeology). Two wells were installed to investigateconditions in the deep saturated interval. Well MW-1D (Figure 2-11) was installed adjacent toshallow well MW-1S as a background well pair. The water sample from MW-1D contained tracelevels of Site contaminants. The occurrence of Site contaminants in the well may be attributed toradial flow away from the Site in the shallow aquifer (Figure 2-3) coupled with a downwardhydraulic gradient observed at this location. An alternative explanation involves an as yetunidentified upgradient source for these contaminants.

The second deep well was installed at the western Site boundary (well MW-3D) adjacent toshallow well MW-3S as a well pair. Again, trace levels of Site contaminants were observed atthis location. The concentrations of TCE and DCE in MW-3D were 50 and 100 times lower thanthose observed in MW-3S, respectively. This suggests little vertical migration of Sitecontaminants over the nearly 60-year history of solvent use at the Site. As mentioned above, thepossibility remains for an unidentified upgradient source for contamination in the lower saturatedzone.

2.2.8 Occurrence of Dense Non Aqueous Phase Liquid

The presence or absence of dense non-aqueous phase liquid (DNAPL) is of interest given itspotential impact on contaminant fate and transport. The occurrence of DNAPL is difficult toconclusively demonstrate. However, several lines of evidence can be used to infer its presence orabsence. These include:

1. Measurable DNAPL in monitoring wells.

2. DNAPL observed in soil samples collected above low-permeability layers.

3. Observed contaminant concentrations in groundwater compared with the correspondingsolubility limit.

Measurable DNAPL in Monitoring Wells

DNAPL has not been observed in any monitoring well. Monitoring well screens generally wereset to intersect the water table and extend at least 10-feet below the water table. In some cases,the well screens fully penetrate the shallow aquifer. The cross-section presented as Figure 2-2illustrates the numerous permeability contrasts penetrated by the borings for on-Site monitoringwells. Monitoring well MW-2S is proximal to a contaminant release point inferred fromchemical analyses of soil gas and soil samples (direct push boring 82; see Section 2.2.3). Thescreen for this well crosses two saturated sand layers bounded above and below by clay.


Given the presence of residual non-aqueous phase liquid in the vadose zone in this boring (seediscussion below), the interfaces between the saturated sand and vertically adjacent clays wouldbe a likely location for the accumulation of DNAPL, if present. None has been observed.

DNAPL Observed in Soil Samples

Soil borings drilled on-Site penetrated multiple interfaces between relatively permeable andimpermeable materials below the water table where DNAPL might collect. Such interfacesincluded those discussed above for boring 2S as well as a pronounced contact between saturatedsand and an underlying clay in boring 3S. The boring for well MW-3D penetrated additionalsand/clay interfaces as illustrated on Figure 2-2. Direct push boring 041 was advanced at least10-feet below the water table and penetrated a pronounced contact between saturated sand and anunderlying clay near the bottom of the boring. Direct push boring 64 encountered a sharp contactbetween saturated sands and an underlying clay layer at a depth of 35 feet.

A portable photoionization detector (PID) reading of 100 relative response units (RRUs) wasnoted at the sand/clay interface discussed above in boring 3S. However, excessive samplemoisture was suspected to cause an inaccurate PID reading as no hydrocarbon odors or stainingwas observed in the sample. A PID reading of 300 RRUs was noted in a soil sample collected inthe saturated sand at the interface with underlying clay in boring 64 although no odor or stainingwas observed. The soil sample was submitted for chemical analyses and contained 0.054 mg/kgof total VOCs. No hydrocarbon odors, PID readings above 2 RRUs, or staining were observed inother samples recovered at permeability contrasts below the water table.

Each of the 10 boreholes advanced on-Site penetrated the entire vadose zone and numerouspermeability contrasts. Hydrocarbon odors, non-zero PID readings and discoloration were notedin several locations as discussed in Section 2.2.5. A brown liquid with a diesel odor wasobserved in the 19-20 foot soil sample in boring 82 (DPS-082-020).

As discussed in Section 2.2.5, the maximum concentration of all the COCs from this sample is140 mg/kg (DPS-082-020) when added together. For comparison purposes, the soil saturationlimit for TCE in soil (conservatively assuming porosity = 0.385, soil density = 1.63 g/cm3, 0W =0.197, and f^ = 0.00022) is 217 mg/kg. Roughly equivalent values are obtained for other COCs.Although some oily material was noted in this sample, the amount of COCs is roughly one-halfof the soil saturation limit (see Section 2.2.5). This is not indicative of non-aqueous phase TCEand may represent the remnants of a historic layer of LNAPL that floated on the historic highwater table. Although the composition of the oily matrix is unknown, the location of boring 82relative to the historic oil/water separator (Figure 1-3) suggests it may consist of a small amountof chlorinated VOCs dissolved in waste oil or diesel fuel.

Observed Groundwater Contaminant Concentrations vs. Solubility Limits

Table 2-5 compares the solubility limit of COCs with the maximum observed contaminantconcentration in groundwater.

A review of Table 2-5 shows that none of the COCs was observed at more than 0.52 percent ofthe corresponding solubility limit. This coupled with the other lines of evidence suggests theabsence of DNAPL.


TABLE 2-5COC Solubility Limits and Maximum Observed Concentrations

ChemicalName (COCs)

BenzeneNaphthaleneTrichloroethene (TCE)

WaterSolubility1

(mg/L)1,75031.71,100

Maximum2 ObservedConcentration in

Groundwater (mg/L)0.0040.0135.778"

Percent of SolubilityLimit

0.00020.040.52

Notes:1 Taken from the "Handbook of Environmental Fate and Exposure Data for Organic Chemicals. Philip H.

Howard. Lewis Publishers, 1990."2 Maximum observed concentration from data collected during the RI, only. Includes geoprobe as well as

monitoring well data and J qualified data.TCE concentration is the sum of the measured TCE concentration at Geoprobe sample station 64 (Figure 2-10) and the concentration of cis-l,2-dichloroethene and vinyl chloride at this station, adjusted to correct forthe reduction in molecular weight during the dechlorination process.

The suspected contaminant release locations are proximal to the historic wash rack and oil/waterseparator (Figures 2-5 through 2-7). This coupled with the lack of DNAPL suggests some of theTCE and PCE detected in soils and groundwater may have been released as an aqueous solution.Some of the contaminants may also have been released as a dissolved fraction of an LNAPL.The remnants of this LNAPL were observed near the former oil/water separator.

2.2.9 Off-Site Sources

At the western limit of the groundwater investigation, well 14S marks one of two contaminantplumes originating from off-Site sources that overlap the plume originating on-Site. Theoverlapping plume can be clearly seen on Figures 2-12 and 2-20. It is recognized by a ten-foldincrease in TCE and lesser increases in other chemicals. The likelihood of contaminationmeasured at well 14S being solely attributable to the Site is considered low. The sudden increasein TCE coupled with another line of evidence supports this interpretation as discussed below.

A 10-fold decline in TCE was observed between wells 14S and EPA sample station WPH 10(Figure 2-13), 300-feet downgradient of well 14S. This rapid decline in TCE concentration,coupled with an increase in VC concentration suggests degradation of TCE is occurring. Asimilar decline was also observed proximal to the Site between MW-3S and MW-10S without,however, the concurrent increase in the concentration of daughter products. Therefore, it appearsunlikely that the 507 ug/L of TCE observed at well 14S could have survived during its 1,400 footmigration from a suspected on-Site release point.

A second overlapping plume has been identified to the north of the Site paralleling andoverlapping the plume originating from the Site (Figure 2-20). The overlapping plume can berecognized by the presence of MTBE. Wells 4S and 1 IS contained MTBE between 4 and 407ug/L (Figure 2-13). The sample collected by EPA at sample location WPH 10 contained MTBEalthough the amount was not quantified. This plume may be attributable to a source located onthe Phillips 66 property north of the Site. This interpretation is supported by the presence of



increasing VOC concentrations (particularly benzene) in off-Site soil gas towards the north(Figure 2-8).

Additional plumes may be present to the northwest of monitoring well 14S. The presence of 60ug/L of PCE measured by EPA at station BWXMO3 (Figure 2-13) suggests a source for thischemical is present near or upgradient of this sampling station. Assessment of groundwaterchemistry beyond the influence of the plume originating from the Site is beyond the scope of thisstudy.

2.3 Summary of Groundwater Contaminant Fate and Transport Modeling

Contaminant fate and transport modeling was conducted to estimate attenuation rates andprovide predictions of the distribution of contaminants in groundwater at various time stepsunder a range of source conditions. An analytical model, BIOCHLOR, as well as a three-dimensional flow and transport modeling program, Visual MODFLOW Pro (Version 3.0) wasused along with a program simulating reactive multi-species mass transport (RT3Dv2.5).

BIOCHLOR is a screening model that simulates remediation by natural attenuation of dissolvedsolvents at chlorinated solvent release sites. Site data from the October 2002 monitoring eventwas input into BIOCHLOR and the model was used to determine reasonable decay rates for Sitecontaminants for use in numerical modeling. BIOCHLOR provides output plots superimposingfield data on trend lines of predicted contaminant concentrations with no degradation and withsequential first order decay. The October 2002 data shows good correlation with the sequentialfirst order decay trend line. BIOCHLOR input and output data are provided in Attachments K ofthe RI Report (HDR, 2003).

The Site conceptual model used in developing the numerical model assumes the shallow aquiferis laterally continuous within the modeled domain and has uniform hydraulic properties.Hydraulic conductivity was determined using the results of three single well slug tests. Thecurrent groundwater contour map shows a general west-northwest hydraulic gradient with asoutherly flow component in the vicinity of the Site. Upgradient and downgradient constant headboundary conditions were assigned based on measured values at monitoring wells within themodel domain. Recharge sources include infiltration due to precipitation, and lateral inflowalong the upgradient model boundary.

The contaminant transport conceptual model involves a vadose zone source that leaches toshallow groundwater. Transport properties, including bulk density, dispersivity, sorption, anddegradation rates, were estimated using both Site data and literature values.

The flow model was calibrated using water table elevation data from October 2002 and hydraulicconductivity values estimated from aquifer tests performed at the Site. Other model inputs werederived from literature values. The contaminant transport model was calibrated by adjusting thecontaminant release scenario and degradation rates for PCE, TCE, DCE and VC. A completediscussion of the model construction, calibration and simulations is provided in Appendix K ofthe RI Report.

The release scenario that provided the best match to current conditions was based on availableSite history coupled with the current observed contaminant concentrations. The release scenario

W.S. Hatch Co. 2^13 HDR Engineering, Inc.Focused Feasibility Study Final Report . July 2004

and contaminant degradation rates are summarized in Table 2-6. The presence of decay products(cis-l,2-DCE and VC) in subsurface soils suggests degradation is occurring in the source.Because the rate of source decay cannot be quantified from available data, a range of potentialsource scenarios was developed. Scenario 1 involves linear decay of the current assumed sourcecondition (15 ug/L PCE and 1,000 ug/L TCE) to zero in the year 2010. Scenario 2 involveslinear decay of the current assumed source condition to zero in the year 2020. Scenario 3involves sustaining the current assumed source condition until 2040 to simulate a worse casescenario. The source term duration for Scenario 3 is based on Site-specific calculations presentedin Appendix K of the RI Report (HDR, 2003). The first and second scenarios are likely torepresent the reasonable range of Site conditions. The third scenario is considered to be veryconservative.

TABLE 2-6Calibrated Transport Model Parameters

Parameter PCE TCE DCE VCSource Condition:

Area

Initial ConcentrationDurationDecay PeriodCurrent Concentration

Degradation Rate

2 grid cells atMW-2S

1,000 ug/L5 yrs

40yrs15 ug/L

0.00047 day'1

2 grid cells atMW-2S

35,000 ug/L45 yrs10 yrs

1,000 ug/L0.00085 day1

NA

NANANANA

0.00092 day1

NA

NANANANA

0.0025 day1

The concentrations of PCE, TCE, cis-1, 2-DCE and VC in the years 2002, 2010, 2025 forScenario 2 are illustrated on Figure 2-21. All scenarios are illustrated in Appendix K of the RIReport. Under this scenario, PCE concentrations decline to below MCLs (5 ug/L) by 2010 andessentially disappear by 2025. In 2010, TCE has declined most dramatically near the source withmore persistence seen in the distal portion of the plume. The area exceeding the TCE MCL (5ug/L) remains fairly constant until sometime after 2010. By 2025 only a small area just west ofthe source is predicted to remain near the MCL.

The behavior of DCE and VC is similar to that of TCE. Although most reduction in DCEinitially occurs near the source, the area exceeding the MCL (70 ug/L) is reduced by about 75percent by 2010 with all remaining DCE nearly degraded by 2025. In the case of vinyl chloride,a small area at the MCL (2 ug/L) is predicted to remain just west of the source area until 2027.Under Scenario 2, all modeled contaminants decline to below MCLs in the off-Site area by theyear 2027. Under Scenarios 1 and 3, all chemicals decline below MCLs in the off-Site area bythe year 2022 and 2057, respectively.

The worst-case scenario (Scenario 3) included a 1.0 mg/L TCE source present over an area of 60x 100 feet and sustained for 36 years. The use of 1.0 mg/L as a source concentration was basedon the range of measured TCE concentrations over the source area (0.15 to 1.3 mg/L). Theduration of the source was based on an estimated mass of TCE remaining in vadose zone soils



and the assumption that the entire source mass eventually leaches into groundwater. Under thisscenario, TCE, PCE, DCE and VC concentrations decline to below maximum contaminant levels(MCLs) in the off-Site areas by the year 2057.

2.4 Baseline Risk Assessment

2.4.1 Contaminants of Concern

The process used to identify the COCs is described in the Baseline Risk Assessment presented inthe RI Report.

There are no COCs in surface soil. In subsurface soil, TCE is the only COC identified. Thefollowing seven VOCs are identified as COCs in groundwater: benzene, cis-l,2-DCE,naphthalene, PCE, TCE, 1,2,4-trimethylbenzene, and VC.

2.4.2 Exposure Assessment . . _ . . . . .

The Site is currently undeveloped and fenced, minimizing human exposure. On-Site exposure islimited to two hypothetical future use scenarios: a hypothetical future worker associated withconstruction or utilities installation at the Site, and a hypothetical future worker inside anybuilding that might be constructed on the Site. In addition, exposures at off-Site locations areevaluated for current and hypothetical future residents. An on-Site residential scenario was notconsidered because the land is currently vacant, is zoned for commercial use and Hatchcointends to develop the land consistent with its current zoning.

Potentially complete exposure pathways for the trench worker include incidental ingestion ofsubsurface soil and inhalation of Site-related VOCs that emanate from subsurface soil to outdoorair. On-Site depth to groundwater ranges from 24 to 30-feet bgs; therefore, the trench workerwould not be exposed directly to groundwater. The dermal exposure pathway is consideredincomplete for all on-Site receptors, based on EPA guidance for evaluating dermal exposures tochemicals (EPA, 2001 b).

The potential exists for a future indoor worker to be exposed to COCs via inhalation of VOCsthat emanate from subsurface soil or groundwater to indoor air in a structure that might be builton the Site. Johnson and Ettinger modeling was used to estimate indoor air concentrations thatmight result from volatilization of chemicals in subsurface soil or groundwater through thevadose zone and a building's foundation to the enclosed space. Inhalation of Site-related VOCsis the only potentially complete exposure pathway for this scenario, because exposure to on-Sitesoils is not anticipated for a hypothetical future indoor worker due to the nature of indoor workeractivities (EPA, 2001a) and lack of COCs in surface soils.

To assess any potential exposures that might be associated with off-Site migration of thegroundwater plume, infiltration of VOC vapors from the groundwater into current orhypothetical future off-Site residences is included in the evaluation. In both the current andfuture scenarios, it is assumed that an adult resident may be exposed to COCs via inhalation ofVOCs that emanate from groundwater to indoor air. The current resident is assumed to live in thesame location as groundwater monitoring well MW-11S. The location of MW-11S was selectedbecause it represents the off-Site sampling location nearest to structures that currently exist near


the Site. A hypothetical future resident is assumed to live in a split-level house, located in thesame location as MW-10S. This location was selected because it is the off-Site well with thehighest contaminant concentrations. Potential exposures for each receptor are calculated basedon the six exposure pathways identified above as potentially complete.

In accordance with EPA methodology (EPA, 1989 and 1992), conservative upper bound defaultexposure assumptions are used for the intake parameters such that the combination of allexposure parameters results in a reasonable maximum exposure (RME) for the exposure pathwayevaluated. The goal of the RME is to quantify the maximum exposure that is reasonablyexpected to occur at a Site, not the worst possible exposure (EPA 1989). At the request of EPARegion VIII, a central tendency exposure (CTE) for each pathway was also evaluated. The CTEis intended to measure the mean or median exposure at a given Site. Use of both RME and CTEestimates is intended to capture the variability in exposure, lifestyles and other factors that leadto a distribution of risk across a population (EPA 1992).

In lieu of quantifying potential risks from direct exposure to off-Site grouridwater that would beassociated with domestic use of the water, groundwater concentrations were compared to MCLsor RBCs. This comparison is illustrated on Figure 2-22 for current Site conditions. A discussionof future Site conditions occurs in Section 2.3.

No domestic groundwater use is known within the area of groundwater inferred to be impactedby contaminants migrating from the Hatchco property. Potentially affected property owners werecontacted by certified mail to ascertain groundwater usage. Respondents have not reported anygroundwater usage. However, use of contaminated groundwater will not be known with certaintyuntil EPA completes work on portions of the NPL Site surrounding the Hatchco study area.

2.4.3 Toxicity Assessment

The purpose of the toxicity assessment is to evaluate the potential for Site-related chemicals tocause adverse health effects in exposed individuals, and to define, to the extent possible, therelation between the degree of exposure to a hazardous chemical and the likelihood of anyadverse health effects.

In this assessment, the potential for noncarcinogenic health effects was evaluated for long-termaverage exposures (i.e., as would occur over a year) by comparing estimated chronic dailyintakes with chemical-specific reference doses (RfDs) from the EPA. The RfD represents a dailyintake at which no adverse effects are expected to occur over a lifetime of exposure, even insensitive subpopulations. Carcinogenic slope factor (CSFs) were used to estimate the incrementallifetime risk of developing cancer that corresponds to the estimated exposure levels calculated inthe exposure assessment. Both RfDs and CSFs are specific to the route of exposure (e.g.,ingestion or inhalation exposure).

Values for RfDs and CSFs from the Integrated Risk Information System Online Database (IRIS,EPA 2002) were used preferentially when available. This computerized database contains EPA-verified toxicity values and EPA regulatory information for many chemicals commonly detectedat hazardous waste sites. EPA extensively reviews and verifies RfDs and CSFs derived for risk


assessment and, once verified, they represent agency consensus. If toxicity values were notavailable from IRIS, then values were obtained from the EPA Region III RBC table (EPA 2003).

Noncarcinogenic and carcinogenic toxicity values used to assess potential risks from the COCsfor the Hatchco Site are presented in Table 2-7.

TABLE 2-7Summary of Toxicity Values

OralCancer Slope

Chemical

Benzene

Factor

(mq/kg-day) 1

0.055 Icis-1 ,2-DichloroetheneNaphthaleneTetrachloroetheneTrichloroetheneTrichloroethene

(old)(provisional)

--

0.054 O0.011 W

0.4 E1 ,2,4-TrimethylbenzeneVinyl chloride

Sources:EH

I

WO

- EPA-NCEA provisional- HEAST- IRIS-Withdrawn from IRIS orRegion VIII

0.72 I

value

HEAST; used at

ReferenceDose

(mg/kq-day)

0.003 E0.01 H0.02 I0.01 I

0.0003 E0.0003 E

0.05 E0.003 I

InhalationCancer Slope

Factor

(mg/kg-day)"1

0.029 1'

--0.02 0

0.006 W0.4 E

--0.0151

the direction of U.S. EPA

ReferenceDose

(mg/kg-day)

0.001 7 E--

0.0009 I0.14 E0.01 E0.01 E

0.0017 E0.028 I

- Other source, as cited in Region III RBC Table (Revised 10/15/03)

2.4.4 Risk Characterization

2.4.4.1 Hypothetical Future On-Site Trench Worker

Tables 2-8 through 2-11 provide a summary of the estimated risks associated with thehypothetical future on-Site trench worker exposure scenario. Estimated cancer risks range from2E-8 (CTE using the old TCE slope factor) to 8E-6 (RME using the provisional TCE slopefactor) and 0.1 for non-cancer end points of toxicity.

2.4.4.2 Hypothetical Future On-Site Indoor Worker

Tables 2-8 through 2-11 provide a summary of estimated risks associated with inhalation ofCOCs that infiltrate into a future on-Site structure. Estimated cancer risks under this scenariorange from 7E-7 (CTE using the old TCE slope factor) to 3E-4 (RME using the provisional TCEslope factor) for inhalation of VOCs infiltrating from subsurface soils and range from 4E-8 (CTEusing the old TCE slope factor) to 6E-6 (RME using the provisional TCE slope factor) for



TABLE 2-8Summary of RME Risk Estimates and Hazard Indices (old TCE slope factor)

On-Site Trench WorkerSoil Soil

Ingestion Inhalation Total

Carcinogenic Risk EstimatesBenzene -cis-1 ,2-DichloroetheneNaphthaleneTetrachloroetheneTrichloroethene (old) 2E-10 1E-07 1E-071 ,2,4-TrimethylbenzeneVinyl chloride

Total: 2E-10 1E-07 1E-07

Noncarcinogenic Hazard QuotientsBenzene . - -- . -cis-1 ,2-DichloroetheneNaphthaleneTetrachloroetheneTrichloroethene 0.004 0.1 0.11 ,2,4-TrimethylbenzeneVinyl chloride

Total: 0.004 0.1 0.1

On-Site Indoor WorkerInhalation,

IndoorIntrusion from

Subsurface Soil

-.

--9E-074E-06

-2E-09

5E-06

••-.--

0.010.0009

0.20.05

0.00001

0.3

Inhalation,Indoor

Intrusion fromGroundwater

1E-09--

•4E-091E-07

--2E-07

3E-07

0.00007'

0.000060.000004

0.0050.00002

0.002

0.007

Off-Site Resident,Inhalation, Indoor

Intrusion from GroundwaterCurrent Future

2E-08 3E-08..

.7E-09 3E-083E-08 3E-07

..

8E-07 1 E-06

9E-07 1E-06

0.0008 0.001..

0.0002 0.00030.000006 0.00003

0.001 0.010.0003 0.00050.004 0.007

0.006 0.02



TABLE 2-9Summary of RME Risk Estimates and Hazard Indices (provisional TCE slope factor)



Carcinogenic Risk EstimatesBenzene —cis-1 ,2-DichloroetheneNaphthaleneTetrachloroethene -- . . . .Trichloroethene (provisional) 7E-09 8E-06 8E-061 ,2,4-Trimethylbenzene . . . . . .Vinyl chloride

Total: 7E-09 8E-06 8E-06

Noncarcinogenic Hazard QuotientsBenzenecis-1, 2-Dichloroethene ..Naphthalene - - -TetrachloroetheneTrichloroethene 0.004 0.1 0.11 ,2,4-Trimethylbenzene .. ..Vinyl chloride . . . .

Total: 0.004 0.1 0.1



Subsurface Soil

• • - ---

•9E-073E-04

--2E-09

3E-04

!

: --. ~0.01

0.00090.2

6.050.00001

0.3

Inhalation,Indoor


1E-09~

.4E-096E-06

'

2E-07

6E-06

0.00007-

0.000060.000004

0.0050.00002

0.002

0.007


Intrusion from GroundwaterCurrent

2E-08~--

7E-092E-06

--8E-07

3E-06

0.0008—

0.00020.000006

0.0010.00030.004

0.006

Future

3E-08•

-3E-082E-05

-1E-06

2E-05

0.001-

0.00030.00003

0.010.00500.007

0.02



TABLE 2-10 iSummary of CTE Risk Estimates and Hazard Indices (old TCE slope factor)



Carcinogenic Risk EstimatesBenzenecis-1 ,2-DichloroetheneNaphthalene --TetrachloroetheneTrichloroethene (old) 6E-1 1 6E-08 6E-081 ,2,4-TrimethylbenzeneVinyl chloride

Total: 6E-11 6E-08 6E-08

Noncarcinogenic Hazard QuotientsBenzenecis-1 ,2-DichloroetheneNaphthaleneTetrachloroetheneTrichloroethene 0.002 0.1 0.11 ,2,4-TrimethylbenzeneVinyl chloride

Total: 0.002 0.1 0.1

On-Site Indoor WorkerInhalation1,

Indoor 'Intrusion from

Subsurface Soil

—' —-

1E-076E-07

-

2E-10

7E-07

—--

0.0070.0006

0.10.04

0.000007

0.1

Inhalation,Indoor


2E-10--

6E-101E-08

-3E-08

4E-08

0.00004-

0.000040.000003

0.0030.00001

0.001

0.004


Intrusion fromCurrent

3E-09«-

1E-096E-09

'

1E-07

1E-07

0.0005-

0.00010.000004

0.00080.00020.003

0.005

GroundwaterFuture

5E-09--

'

6E-096E-08

-3E-07

4E-07

0.0002--

0.000060.000005

0.0020.00010.001

0.00



Table 2-11Summary of CTE Risk Estimates and Hazard Indices (provisional TCE slope factor)



Carcinogenic Risk EstimatesBenzenecis-1 ,2-Dichloroethene -- --NaphthaleneTetrachloroelhene ' -Trichloroethene (provisional) 2E-09 4E-06 4E-061 ,2,4-TrimethylbenzeneVinyl chloride

Total: 2E-09 4E-06 4E-06

Noncarcinogenic Hazard QuotientsBenzene . . . . . .cis-1, 2-Dichloroethene ~NaphthaleneTetrachloroetheneTrichloroethene 0.002 0.1 0.11 ,2,4-TrimethylbenzeneVinyl chloride

Total: 0.002 0.1 0.1



Subsurface Soil

--—

.1E-074E-05

~

2E-10

4E-05

~'

0.0070.0006

0.10.04

0.000007

0.1

Inhalation,Indoor


2E-10.

--6E-109E-07

--

3E-08

9E-07

0.00004'

0.000040.000003

0.0030.00001

0.001

0.004


Intrusion fromCurrent

3E-09—-

1E-094E-07

~

1E-07

5E-07

0.0005-'-

0.00010.000004

0.00080.00020.003

0.005

GroundwaterFuture

5E-09—

~6E-094E-06

-3E-07

4E-06

0.0002--

0.000060.000005

0.0020.00010.001

0.00



inhalation of VOCs infiltrating from groundwater under the Site. Irrespective of the assumedsource of VOCs (i.e., soil or groundwater), calculated non-cancer risks do not exceed unity.

2.4.4.3 Off-Site Residents

Tables 2-8 through 2-11 provide a summary of estimated risks associated with inhalation ofCOCs that infiltrate into current and hypothetical future off-Site residences. Estimated cancerrisks for off-Site residents under the current scenario range from 1E-7 (CTE using the old TCEslope factor) to 3E-6 (RME using the provisional TCE slope factor) and range from 4E-7 (CTEusing the old TCE slope factor) to 2E-5 (RME using the provisional TCE slope factor) under thehypothetical future scenario. Non-cancer risks for both off-Site scenarios fall well below unity.

2.4.5 Ecological Evaluation and Characterization

No ecologically sensitive scenarios on-Site were identified due to the lack of suitable habitat, the-location of the-Site in a developed area, and restrictions to Site access (i.e.v fencing around theSite property).

The present and predicted future limits of the groundwater contaminant plume originating fromthe Site preclude the present or future discharge of contaminated groundwater to the Great SaltLake.

A reconnaissance of the Site vicinity was conducted to identify any locations where groundwaterdischarges to surface water. The Site survey revealed no surface water downgradient of the Siteor within the plume (no streams or wetlands were noted between the Hatchco property and 1100West Street).

Mill Creek is a perennial stream located east of the Site and flows to the north. The probability ofSite impacts to Mill Creek are considered to be very low for the following reasons:

1. It is located hydraulically upgradient from the Site.

2. The depth to groundwater exceeds 20-feet.

3. The creek is concrete lined in the vicinity of the Site.

Given the distance of the Site to the Great Salt Lake (approx. 2.5 miles) and the fact that nosurface water features were identified within the Hatchco plume boundaries that could bereceiving groundwater discharge, it is concluded that the Site poses no adverse ecologicalimpacts.


3.0 SUMMARY OF PREVIOUS REMEDIAL MEASURES

Beginning in 1995, TRTech performed additional investigation, remediation, and remedialoversight of contaminated areas associated with historical Site structures. In addition, TRTechinstalled an active groundwater remediation system in 1998. The following text summarizesthese investigative and remedial efforts. Locations of the features described in the followingsubsections are shown on Figure 1-3.

3.1 Oil/Water Separator

Hatchco is believed to have used an underground concrete tank to separate waste product fromwater that would be discharged into the sewer. The underground oil/water separator wasremoved and disposed of by W.L. Shelton construction under the supervision of TRTech in1998. TRTech took soil samples at a depth of about one meter below the surface of theexcavation and reported traces of petroleum hydrocarbons, but no chlorinated solvents.

3.2 French Drain

During demolition of Site facilities in 1998, Hatchco found a drainage pipe connecting a truckwashing facility (wash rack) to a french drain located north and west of the wash rack. Thedrainage pipe reportedly had been plugged, preventing water from the wash rack from enteringthe french drain. The french drain was excavated by W.L. Shelton Construction under thesupervision of TRTech, in 1998. Oily residue in the drain was tested by TRTech and reported tobe nonhazardous, although chlorinated solvents were present in the sample. The oil wasreportedly disposed of by VJ Environmental.

According to Mr. Shelton, he encountered coarse gravel in the french drain at a depth ofapproximately 6 feet. TRTech had materials from the french drain area that showed signs ofstaining removed to the "soil farm pad" located on the northwest corner of the Site. TRTechreported treating the soils with water and nutrients as part of a natural attenuation plan.

3.3 Underground "Waste Oil" Storage Tank

In August of 1995, about the same time that Hatchco ceased operations at the Site, Hatchco's"waste oil" underground storage tank was removed. Material from this underground storage tankwas characterized as containing waste petroleum products, solid waste products, carbondisulfide, methylene chloride, TCE, lead, and mercury. The tank contents were disposed of byPMT Services, Inc., under the direction of TRTech.

After removal of the tank, soil testing showed the presence of petroleum products (benzene,toluene, ethylbenzene, xylenes, naphthalene [BTEXN]) and 1,1-dichloroethane and 1,2-dichloroethene in the soils surrounding the underground storage tank area. TRTech undertookremediation measures to correct the contamination around the pulled tank, and on February 28,1996, Kent Gray of the Utah Solid and Hazardous Waste Control Board issued a no furthercorrective action letter, and the.Site was closed.


3.4 Groundwater Remedial Efforts

In 1998, TRTech installed a "five-well, low volume air sparging system to remove vinyl chloridefrom the shallow aquifer." TRTech reported in 1998 that the system was working as expectedand vinyl chloride contamination at the Site should "reach the appropriate standard in fromtwenty six to seventy six months." TRTech's 2001 analysis indicates that vinyl chloride has beenreduced from 1,560 ug/L down to 16.2 ug/L and tetrachloroethene was reduced from 750 ug/L tonondetect measured 10 meters from the closest sparger point. The last vinyl chloride sample was35.5 ug/L, trichloroethene was 152 ug/L, and tetrachloroethene was nondetect. .

A low water table condition coupled with shallow sparge wells has resulted in intermittentoperation of the sparge system since initiation of the RI/FS.


4.0 REMEDIAL ACTION OBJECTIVES

4.1 Introduction

This portion of the FFS identifies Remedial Action Objectives (RAOs) for the Site.

General RAOs include:

• Prevent unacceptable exposure risk to current and future human populations posed bySite contaminants.

• Restore groundwater to beneficial use.

In addition, the National Oil and Hazardous Substance Pollution Contingency Plan (NCP)requires establishing RAOs specifying:

1) Contaminants of concern

2) Potential exposure pathways

3) Remediation goals

The NCP goes on to explain:

Preliminary remediation goals (PRGs) are developed based on readily available information,such as chemical-specific applicable or relevant and appropriate requirements (ARARs) or otherreliable information. Preliminary remediation goals should be modified, as necessary, as moreinformation becomes available during the Remedial Investigation and Feasibility Study (RI/FS).Final remediation goals will be determined when the remedy is selected. Remediation goals shallestablish acceptable exposure levels that are protective of human health and the environment andshall be developed by considering the following:

• ARARs

• Risk-based clean-up goals (based on a hazard index equal to 1 or cancer risk equal to 1E-4).

• Technical limitations such as detection limits.

• Factors related to uncertainty.

• Potential ecological impacts.


4.2 Contaminants of Concern

The baseline risk assessment included in the RI report identifies the following media-specificCOCs:

S urface soi 1 s: NoneSubsurface soils: TCESurface water: NoneGroundwater: TCE, PCE, VC, cis-l,2-dichloroethene, naphthalene, benzene and

1,2,4-trimethylbenzene.

4.3 Potential Exposure Pathways

The baseline risk assessment included in the RI report identifies the following exposurepathways and environmental media as significant:

a) Various COCs occur in on- and off-Site groundwater above federal MCLs. There is nocurrent groundwater use on-Site and no evidence of current off-Site usage within thecontaminant plume solely attributable to Hatchco. Hypothetical future on- and off-Siteingestion of contaminated groundwater (or unknown current off-Site groundwater use)poses a potential health risk above a level of concern. Therefore, groundwater is amedium of concern both on- and off-Site.

In addition to exposure pathways identified in the risk assessment, TCE present in subsurfacesoil may migrate to groundwater contributing to the exposures described above.

4.4 Remediation Goals

Preliminary remediation goals are discussed below by medium.

Subsurface soils - Remediation of subsurface soils would be pursued to reduce the potential forvapor intrusion into hypothetical future on-site structures and to reduce the potential forcontaminant migration from soils to groundwater. Based on Soil Screening Guidance (TechnicalBackground Document, EPA, 1996a), the default threshold concentration for TCE in soils isdriven by the potential for it to act a source for groundwater contamination. The default value is60 ug/kg (based on a 20-fold dilution/attenuation factor).

Groundwater - Preliminary remediation goals will be the MCLs or risk-based concentrationsbased on a hazard index of one or cancer risk of 1E-4 assuming residential RME throughingestion, only. Chemical-specific PRGs for groundwater are provided in Table 4-1.


TABLE 4-1Preliminary Remediation Goals

Chemical

TrichloroethenePerchloroetheneVinyl chlorideCis-1, 2-dichloroetheneBenzenenapthalene1,2,4-trimethylbenzene

MCL/MCLG3

(ug/L)

5 / 05 / 02 / 0

70/70

5 / 0NANA

ResidentialRisk-Based

Concentration5

(ug/L)

NANANANA

NA6.512

StateGroundwater

QualityStandards

(ug/L)552

70

5NANA

PreliminaryRemediationGoal (ug/L)

552

70

56.512

a MCLs are consistent with Utah Primary Drinking Water Standards.On-Site land use is expected to be commercial/industrial.



5.0 APPLICABLE OR RELEVANT AND APPROPRIATEREQUIREMENTS

Remedial actions must attain a general level of cleanup that assures protection of human healthand the environment, is cost-effective, and uses permanent solutions and alternative treatmenttechnologies or resource recovery technologies to the maximum extent practicable. In addition,the Superfund Amendments and Reauthorization Act (SARA) requires that any hazardoussubstance or pollutant and contaminant remaining on site meet the level or standard of controlestablished by ARAR standards, requirements, criteria, or limitations established under anyfederal environmental law, or any more stringent standards, requirements, criteria, or limitationspromulgated in accordance with a state environmental statute.

A requirement may be either applicable or relevant and appropriate to remedial activities at a site(but not both). Applicable requirements are those cleanup standards, standards of control, andother substantive environmental protection requirements, criteria, or limitations promulgatedunder federal or state law that specifically address a hazardous substance, pollutant, contaminant,remedial action, location, or other circumstances at a site. In other words, they would be legallyapplicable notwithstanding the Comprehensive Environmental Response, Compensation andLiability Act (CERCLA).

If a requirement is not applicable, it may still be relevant and appropriate. The basicconsiderations are whether the requirement (1) regulates or addresses problems or situationssufficiently similar to those encountered at the subject site (i.e. relevance), and (2) is appropriateto the circumstances of the release or threatened release, such that its use is well suited to theparticular site. A requirement might be relevant but not appropriate for a specific site; in thiscase, the requirement would not be an ARAR. Determining whether a requirement is relevantand appropriate is site-specific and must be based on best professional judgment. This judgmentis based on a number of factors including the characteristics of the remedial action, the hazardoussubstances present at the site, and the physical circumstances of the site and of the release.

Compliance with all requirements found to be applicable or relevant and appropriate is requiredunder SARA. Waivers of ARARs may be obtained under the provisions of SARA under certaincircumstances (CERCLA Section 121(d)(4)). These waivers apply only to meeting ARARs withrespect to remedial actions on-site; other CERCLA statutory requirements, such as therequirement that remedies be protective of human health and the environment, cannot be waived.Chemical-, Action- and Location-Specific ARARs for the Site are summarized on Tables 5-1through 5-3.


TABLE 5-1Chemical-Specific ARARs

Standard, Requirement or Criteria DescriptionPotentiallyApplicable

PotentiaUyRelevant andAppropriate

Comment

'EDERALClean Water Act (33 USC Sect. 1351-1376)Ambient Water Quality Criteria (40 CFR Part131; Quality Criteria for Water, 1976, 1980,1986, 1987; Ambient Water Quality Criteriabr Selenium, 1987)

Requires EPA and states toestablish ambient water qualitycontrol criteria (AWQC) andstandards, respectively, for surfacewater based on use classificationsand the criteria stated underSections 304(a) and 303 of the

lean Water Act.

No No

Federal (or State) freshwater AWQCs are notconsidered to be ARAR as no surface watermpacts have been identified or are anticipated.

Standards would be applicable to any surfacedischarges of contaminated water tourisdictional waters, but not discharges to

POTWs.

Clean Air Act (42 USC Sect. 7401-7642)National Ambient Air Quality Standards (40CFR Part 50)

Establishes ambient air qualitystandards for certain "criteriapollutants" to protect public healthand welfare.

No Noimpact on NAAQS are anticipated by current

site conditions or the remedial action.

National Emissions Standards for HazardousAir Pollutants (40 CFR Part 61)

Establishes emission standards forcertain industrial pollutants andsources.

No No

NESHAP's are not considered to be ARARsBecause estimated air emissions from Site wastesare anticipated to be well below levels ofconcern, as described in the baseline riskassessment included in the remedialInvestigation Report (Hatchco, 2003).

National Primary Drinking Water Standards40 CFR Part 141FR 8750 (1990)

Establishes maximum contaminantlevels (MCLs) for specificcontaminants which are health-based standards for public drinkingwater systems.

Yes

Although there are no current or anticipatedimpacts on public drinking water systems, MCLsmay be applicable under UAC R311-211-5,unless a less stringent action level is establishedunder the rule, an alternate corrective actionconcentration limit (ACACL) is adopted, or anACL is established under CERCLA.

National Secondary Drinking Water Standards40 CFR Part 143

Establishes secondary maximumcontaminant levels (SMCLs) whichare non-enforceable guidelines forpublic drinking water systems to Yesprotect the aesthetic quality of thewater.

Although there are no current or anticipatedimpacts on public drinking water systems, MCLsmay be applicable under UAC R311-211-5,unless a less stringent action level is establishedunder the rule, an alternate corrective actionconcentration limit (ACACL) is adopted, or anACL is established under CERCLA.




Standard, Requirement or Criteria Description PotentiallyApplicable

PotentiallyRelevant andAppropriate

Comment

Maximum Contaminant Level GoalsMCLGs) PL No. 99-339, 100 Stat. 642

(1986), FR 8750 (1990)

Establishes drinking water qualitygoals set at a level at which noadverse health effects may arisewith an adequate margin of safety.

No

There are no current or anticipated impacts onpublic drinking water systems.

No

STATEDefinitions and GeneralWater Quality Act UAC R317-1

Requirements of Utah Provides definitions and generalrequirements for waste dischargesto waters of the State of UtahEstablishes use designationsStatewide Water QualityStandards.

Yes

Would be applicable to any discharge of treatedor untreated groundwater to surface water, butnot discharges to a POTW.

Utah Primary Drinking Water Standards UACR309-200-5

Establishes state primary drinkingwater standards and/or actionlevels.

Yes

Although there are no current or anticipatedmpacts on public drinking water systems, MCLs

may be applicable under UAC R311-211-5,unless a less stringent action level is establishedunder the rule, an alternate corrective actionconcentration limit (ACACL) is adopted, or anACL is established under CERCLA.

Groundwater Quality Standards UAC R317-6-2

Establishes state groundwaterquality standards. Yes

!onsidered applicable for protection ofuncontaminated groundwater and relevant andappropriate for corrective action unless analternate corrective action concentration limit(ACACL) is adopted, or an ACL is establishedunder CERCLA.

Alternate Corrective Action ConcentrationLimits UAC R317-6-6.15G

Allows for the proposal of alternatecorrection action concentrationlimits (ACACLs) that are higherthan those specified in UAC R317-6-2.

Yes

ACACLs may apply.






Comment

lorrective Action Clean-up Standards at USTand CERCLA sites UAC R311-211-5

Provides minimum standards andalternatives for cleanup ofregulated substances, hazardousmaterials, and hazardoussubstances at CERCLA sites inUtah.

Yes

Applicable.



TABLE 5-2Location-Specific ARARs


PotentiaUyRelevant andAppropriate

Comment

FEDERALE.G.. 1 1988 Protection of Floodplains(40 CFR 6.302 and Appendix A)

E.O.. 1 1990 Protection of Wetlands (40CFR 6.302(a) and Appendix A)

Clean Water Act Section 404 (33 USC1251, etseq; 40 CFR 230, 231)

Endangered Species Act (16 USC 1531et seq; 50 CFR 200, 50 CFR 402

Fish and Wildlife Coordination Act (16USC 661 et seq; 40 CFR 6.302(g))

Jmits activities in floodplains. Floodplains defined as "the lowland and relativelylat areas adjoining inland and coastalwaters including flood prone areas of off-shore islands, including at a minimum,that area subject to a one percent or greaterchance of flooding in any given year."Federal agencies must evaluate thepotential effects of actions taken in aloodplain and avoid adverse impacts fromremedial activities.

Minimizes adverse impacts on areasdesignated as wetlands.

Requires Federal agencies to avoid, to theextent possible, adverse impacts associatedwith destruction or loss of wetlands.Regulates the discharge of dredged or fillmaterial into waters of U.S. Consultationwith the Regional Response Teamrequired.Protects endangered species andthreatened species and preserves theirhabitat. Requires coordination with federalagencies for mitigation of impacts.

Requires coordination with federal andstate agencies on activitiesaffecting/modifying streams or rivers if theactivity has a negative impact on fish orwildlife.

No

No

No

No

No

No

No

No

No

No

The Site lies outside the 100-yearloodplain.

Wetlands are not present on the Site.

Wetlands are not present on the Site.

The Site is not considered to be habitatfor endangered species.

No streams or rivers exist on the Site.



TABLE 5-2Location-Specific ARARs

Standard, Requirement or Criteria

National Historic Preservation Act(NHPA) (16 USC 470 et seq.; 40 CFR6.301(b); 36 CFR Part 63, Part 65, Part800)

Wilderness Act ( 1 6 USC 1 3 1 1 , 1 6 USC668; 50 CFR 53, 50 CFR 27)

Wild & Scenic Rivers Act (16 USC1271;40CFR6.302(e))

Resource Conservation and RecoveryAct (RCRA), Subtitle D (40 CFR258.10-15)

Description

Requires the preservation of historicproperties included in or eligible for theNational Register of Historic Places and tominimize harm to National HistoricLandmarks.Limits activities within areas designated aswilderness areas or National WildlifeRefuge Systems.

Protects rivers that are designated as wild,scenic, or recreational.

New municipal solid waste facilities mustmeet certain location standards. Theseinclude location restrictions on proximityto airports, floodplains, wetlands, faultareas, seismic impact zones, and unstableareas.

PotentiallyApplicable

No

No

No

No


No

No

No

No

Comment

Mo historic features are known to exist onthe Site.

The Site is not within a federally-ownedarea designated as a wilderness area or aNational Wildlife Refuge System.

No alternatives anticipate impacts on anyWild and Scenic River.

No alternatives anticipate construction ofa new municipal solid waste facility.



TABLE 5-3Action-Specific ARARs



Comment

FEDERALClean Water Act (33 USC Sect. 1351-1376) Ambient Water Quality Criteria(40 CFR Part 131; Quality Criteria forWater, 1976, 1980, 1986, 1987; AmbientWater Quality Criteria for Selenium,1987)

Clean Air Act (42 USC Sect. 7401-7642)New Source Performance Standards (40CFR 60)

Solid Waste Disposal Act (SWDA) asamended by the Resource Conservationand Recovery Act of 1976 (RCRA) (42USC Sect. 6901-6987) Criteria forClassification of Solid Waste DisposalFacilities and Practices (Subtitle D) (40CFR Part 257)

Solid Waste Closure (40 CFR 259.60 b,c,h,l,j)

Identification and Listing of HazardousWastes (Subtitle C) 40 CFR part 261

Requires EPA and states toestablish ambient water qualitycontrol criteria (AWQC) andstandards, respectively, forsurface water based on useclassifications and the criteriastated under Sections 304(a) and303 of the Clean Water Act.Bstablishes emission standards forcertain categories of industrialstationary sources.

Establishes criteria for use indetermining which solid wastedisposal facilities and practicesDose a reasonable probability ofadverse effects on health.

Placement of Cap over solid wastelandfill.

Defines those solid wastes whichare subject to regulation ashazardous wastes under 40 CFRParts 262-265 and Parts 124, 270,and 271.

Yes

No

No

No

No

No

No

No

No

Standards may be applicable to alternatives thatwovide for surface water discharges of

contaminated water to jurisdictional waters (notncluding discharges to POTWs).

No impact on NAAQS are anticipated by currentsite conditions or the remedial action.

ône of the remedial alternatives include theconstruction of a non-hazardous solid wastelandfill.

None of the remedial alternatives include theconstruction of a non-hazardous solid wastelandfill.Although some remedial alternatives may involvethe treatment or disposal of TCE and PCEcontaminated groundwater, these extractedgroundwaters are not expected to exhibit hazardouscharacteristics and are thus expected to fall underthe 40 CFR 261.3(a)(2)(iv) exemption. Thus,RCRA Subtitle C is neither applicable or relevantand appropriate.




Standard, Requirement or Criteria DescriptionPotentiallyApplicable


Comment

Standards Applicable to Generators ofHazardous Waste (Subtitle C) 40 CFR

'art 262

Establishes standards forgenerators of hazardous waste. No No

ône of the remedial alternatives involve thegeneration of hazardous waste, as above.

Standards Applicable to Transporters ofHazardous Waste (Subtitle C)40 CFR Part 263

Establishes standards which applyto persons transporting hazardouswaste within the US if thetransportation requires a manifestunder 40 CFR Part 262.

'tone of the remedial alternatives involve theransportation of hazardous waste off-site.

No No

Standards for Owners and Operators oflazardous Waste Treatment, Storage,and Disposal Facilities (Subtitle C)40 CFR Part 264

Establishes minimum nationalstandards which define theacceptable management ofhazardous waste for owners andoperators of facilities which treat,store, or dispose hazardous waste.

No No

'tone of the remedial alternatives involve theTeatment. Storage, or Disposal of hazardouswastes, as above.

interim Standards for Owners andOperators of Hazardous WasteTreatment, Storage, and DisposalFacilities (Subtitle C)40 CFR Part 265

Establishes minimum nationalstandards which define theacceptable management ofhazardous waste during the periodof interim status and untilcertification of final closure or ifthe facility is subject to post-closure requirements, until post-losure requirements, until post-

closure responsibilities arefulfilled.

of the remedial alternatives involve thetreatment. Storage, or Disposal of hazardouswastes, as above.

No No

Hazardous Materials Transportation Act(49 USC Sect. 1801-1813; 49 CFR Parts107, 171-177)

Regulates transportation ofhazardous materials. No No

None of the remedial alternatives involve thetreatment. Storage, or Disposal of hazardouswastes, as above.




Standard, Requirement or Criteria

Land Disposal40 CFR Part 268

Underground Injection ControlRegulations 40 CFR 144-147

National Pollutant Discharge EliminationSystem 40 CFR parts 122, 125

Guidelines establishing Test Proceduresx>r the Analysis of Pollutants40 CFR 136

Description

Establishes a timetable forrestriction of burial of wastes andother hazardous materials.

Provides for protection ofunderground sources of drinkingwater.

Requires permits for the dischargeof pollutants from any pointsource into waters of the UnitedStates.

Specific analytical procedures forNPDES applicants and reports.

PotentiallyApplicable

No

No

Yes

Yes


No

Yes

Comment

LDRs are inapplicable because any placement oflazardous waste (if any) is anticipated to occurwithin a Area of Contamination (Site boundaries).

Potentially relevant and appropriate to injection ofchemical additives. However, in no event would apermit be required for alternatives involvinginjection of chemical additives, as provided underCERCLA Section 121(c).Potentially applicable only to alternatives whereremedial action involves discharge to surfacewaters. Discharge options include discharge tostorm sewer. Would not apply to discharges toPOTW.Potentially applicable to alternatives wherecontaminated waters would be discharged tosurface waters. Would not apply to discharges toPOTW.

STATE

Fugitive Dust Control UAC R307-101

Small Source Exemption de-minimisemissions UAC R307-413-2

Well Drilling and Completion StandardsUAC R655-4

General requirements forcompliance with NationalAmbient Air Quality Standards.

Establishes requirements forexemption of a new source of airpollution from the notice of intentand approval order requirements.

Establishes standards for drillingand abandonment of wells.

Yes

Yes

Yes

Earthwork would be required under the alternativeinvolving capping

New sources of air pollution may result fromtreatment of contaminated soil by vapor extractionor by treatment of groundwater by air stripping.Emissions will not exceed the 5 ton/yr limit underthis regulation.Requirements are applicable for installing orabandoning wells.






Comment

Hazardous Waste GeneratorRequirements UAC R315-5

Establishes standards forhazardous waste generators.

No No

Although some remedial alternatives may involve:he treatment or disposal of TCE and PCE;ontaminated ground water, these extractedgroundwaters are not expected to exhibit hazardouscharacteristics and are thus expected to fall underthe 40 CFR 261.3(a)(2)(iv) exemption. Thus,RCRA Subtitle C is neither applicable or relevantand appropriate.

Jnderground Injection Control Program,UAC R317-7

'rohibits underground injectionexcept as authorized by permit.

No Yes

Potentially relevant and appropriate to the injectionof additives. However, in no event would a permitbe required for alternatives involving injection ofchemical additives, as provided under CERCLASection 121(c).

Discharges to Surface Water UAC 317-8, UAC R317-2-3

Protection of surface watersagainst degradation resulting fromjoint source discharges.Maintains and protects existing instream water uses includingprotecting streams with higherwater quality than the establishedstandards.

Yes

Potentially applicable to alternatives wherecontaminated waters would be discharged tosurface waters. Would not apply to discharges toPOTW.

Definitions and General RequirementsUtah Water Quality Act UAC R317-1

of Provides definitions and generalrequirements for waste dischargesto waters of the State of UtahEstablishes use designationsStatewide Water QualityStandards.

Yes

Would be applicable to any discharge of treated oruntreated groundwater to surface water, but notdischarges to a POTW.



6.0 SCREENING OF REMEDIAL TECHNOLOGIES

6.1 Introduction

The purpose of this section of the FFS is to identify technologies to be considered forremediating contamination at the Site. The remedial technologies retained after screening areassembled into remedial alternatives for screening and detailed and comparative analyses.

The technologies are not evaluated against each other but are evaluated in terms of theirtechnical implementability. The need for treatability or pilot studies is addressed in thediscussion of each technology.

6.2 General Response Actions

General response actions are broad classes of remedial activities intended to satisfy remedialaction objectives. The following general response actions are considered to be potentiallyapplicable:

No Action - leave the Site "as is," with no provisions for monitoring or control.

Institutional Controls - impose legal or administrative measures to restrict exposure tocontaminants.

Containment - target source zones in the subsurface and physically restrict contaminant mobilityusing engineered controls.

Collection/Extraction - extract groundwater and/or non-aqueous phase liquids (NAPL).

Treatment - Use above ground or in-situ treatment processes to reduce toxicity, mobility, andvolume of contaminants.

Disposal - Relocate treated or untreated wastes in a manner that reduces its potential interactionwith the public and the environment.

These response actions may be implemented alone or in combination.

6.3 Environmental Media Targeted for Remediation

Potential media-specific targets for remedial action include contaminated unsaturated zone soils(vadose zone) and contaminated groundwater. The RI determined that contaminated vadose zonesoils do not pose a health risk above a level of concern for current and plausible future Siteoccupants. However, contaminated vadose zone soils must also be evaluated as a potentialcontinuing source for groundwater contamination and are considered a potential target forremedial action. Chlorinated VOCs occur in on- and off-Site groundwater at concentrationsexceeding federal and state MCLs.


6.4 Technology Screening Criteria

Potentially applicable technologies for chlorinated solvents were organized by general responseaction categories. A strong preference for proven remedial technologies was exercised and thesetechnologies were screened with respect to their suitability for use at this site. Screening wasbased primarily on applicability to the waste types, concentrations and site-specific geology andhydrogeology.

Specific criteria used in the screening consisted of the following:

1. Applicability to the waste materials or environmental media in contaminated areas.

2. Implementability at the Site, based on Site-specific conditions such as depth ofcontaminated zones, materials, or obstructions.

3. Record of successful application of the technology at full-scale.

In this screening, remedial technology types were eliminated,from consideration if they aredifficult to implement due to Site constraints, contaminant characteristics, or if the technologyhas not been proven to date to effectively control chlorinated VOCs. The screening criteria ofimplementability and effectiveness are applied based on published information, experience withthe technologies, knowledge of the Site characteristics, and engineering judgment.

6.5 Evaluation of Candidate Technologies

Remedial technologies considered under each of the general response actions are described andevaluated in Tables 6-1 and 6-2. A range of alternatives were developed from the technologiesretained on Tables 6-1 and 6-2 and subjected to screening and detailed and comparative analysisin Sections 8.0 and 9.0.


TABLE 6-1Identification and Screening of Potentially Applicable Remedial Technologies

For the Vadose Zone (Source Area)

General Response Action /Remedial Technologies Description Screening Comments Applicability

No Action No remedial measures taken. Consideration of the no action alternative is requiredby 40 CFR 300.68.

Yes, retainedas a baseline

Institutional ControlsLand Use Restrictions

Requirement for VOC vapor mitigation in futurestructures.

Vapors originating from vadose zone soils do notpresent a risk above a level of concern.

No

ContainmentLow Permeability Barriers• Soil Cap• Concrete/Asphalt Cap• Geomembrane Cap

Install cover (of compacted clay, concrete/asphalt, oran impermeable geomembrane cover) overcontaminated soils to minimize infiltration of waterand minimize leaching of contaminants intogroundwater.

Although source materials are limited, thistechnology is retained because it may reduceleaching of contaminants to groundwater and it isrelatively inexpensive and easy to implement.

Yes

In-Situ TreatmentSoil Vapor Extraction

In-Situ biological/chemicalremediation

Apply a vacuum to a vertical or horizontal slottedpipe installed in soils contaminated w/VOCs.

Indigenous or inoculated micro-organisms degradeorganic contaminants found in soil, converting themto innocuous end products. Nutrients, oxygen, wateror other amendments may be used to enhancebioremediation and contaminant desorption fromsubsurface materials.

Limited source materials. Would require a pilot testprior to full-scale design. May require off gastreatment.Enhanced bioremediation is usually less expensivethan above-ground technologies, does not requirewaste extraction or excavation. However, thistechnology is difficult to apply to the vadose zone asit requires anaerobic conditions.

Degradation products (VC), however, can be moretoxic than the parent compounds and enhancementtechnologies may be costly or technologicallychallenging. In addition, the effectiveness of thetechnology for halogenated VOCs is significantlyless certain than for fuel hydrocarbons. In addition,highly chlorinated organics can be toxic tomicroorganisms. Site specific conditions such asheterogeneity, stratification, and high clay contentalso reduce the effectiveness of this technology.

Yes

No




For the Vadose Zone (Source Area)

General Response Action /Remedial Technologies

Description Screening Comments Applicability

Ex-Situ Treatment/DisposalExcavation w/On-Site LandFarming

Excavate contaminated soils and thin-spread on-Siteto volatilize chlorinated VOCs prior to replacementin the excavation or off-Site disposal.

Excavation w/Off-Site Disposal Excavate contaminated soils and dispose off-Site.

The contaminated interval that would be targeted forexcavation is between one and three-feet thick andoccurs at a depth of 20-feet. The sum of allchlorinated VOCs in the most contaminated samplefrom this interval is 100 mg/kg. The dilute nature ofthe contamination in this interval coupled with theneed to remove excessive overburden to access thecontamination renders excavation potentiallyimpractical.In addition, volatile contaminants may requirepretreatment to prevent volatilization into theatmosphere, which would cause air pollution.

See discussion under Excavation w/on-Site LandFarming.

Yes

Yes



TABLE 6-2 iIdentification and Screening of Potentially Applicable Remedial Technologies

For Groundwater '•

General Response Action /Remedial Technologies Description Screening Comments

Consideration of the no action alternative isrequired by 40 CFR 300.68.

Applicability

No Action No remedial measures taken. Yes, retainedas a baseline

Moderate implementability. Legal servicerequired. :

Not required per Baseline Risk Assessment.

Institutional ControlsLand Use Restrictions

Prohibit water wells in areas of groundwatercontamination. Possible mechanisms includeestablishing an overlay district for the affected areas ofthe NPL Site to be administered by the appropriatemunicipality.

Requirement for VOC vapor mitigation in futurestructures.

Yes

No

Monitored Natural AttenuationGroundwater Monitoring

Allow naturally occurring processes (e.g., dispersion,adsorption, biological and chemical reactions) toreduce contaminant levels. Periodically sample wells todemonstrate attenuation occurring in accordance withnumerical performance standards.

Easily implemented. Requires technical staffand laboratory.

Yes

ContainmentVertical Barriers

Permeable Reactive Barrier

Excavate a trench and backfill with low permeabilitysoil-bentonite mixture to make a barrier to groundwaterflow.

Install vertical treatment wall of chemical media thatreacts and degrades contaminants as groundwaterpasses through the wall.

Lower bounding surface of shallow aquiferlies over 40 feet deep. It is impractical toinstall a slurry wall to this depth byconventional means. Therefore, thistechnology is not retained.

Lower bounding surface of shallow aquiferlies over 40 feet deep. It is impractical toinstall a reactive barrier at these depths.Considered innovative and unproven.Therefore, this technology is not retained.

No

No




For Groundvvater


In-Situ TreatmentIn-Situ biological/chemicalremediation

Steam Sparging with Vapor PhaseExtraction

In-situ injection of a hydrogen source or colloidal iron.The hydrogen source relies on microorganisms in theaquifer to break down both the injected material (toproduce hydrogen) and the contaminants (via reductivedechlorination). Injection of colloidal iron triggers achemical reaction in the aquifer which results in thedegradation of chlorinated solvents. This reaction alsocreates conditions which may enhance biologicdegradation.

Inject steam into saturated zone to remove VOCs fromgroundwater into soil vapor by volatilization. Theaddition of oxygen also enhances the aerobicmetabolism of vinyl chloride.

Enhanced bioremediation is usually lessexpensive than above-ground technologies,does not require waste extraction orexcavation.

Degradation products (VC), however, can bemore toxic than the parent compounds andenhancement technologies may be costly ortechnologically challenging. In addition, theeffectiveness of the technology forhalogenated VOCs is significantly less certainthan for fuel hydrocarbons. In addition, highlychlorinated organics can be toxic tomicroorganisms. Site specific conditions suchas heterogeneity, stratification, and high claycontent also reduce the effectiveness of thistechnology.

Although considered an innovativetechnology, it is retained because it isimplementable as compared with slurry wallsand reactive barriers.

This treatment technology is designed forSVOCs and fuels. VOCs also can be treated,but there are more cost-effective processes forsites contaminated with VOCs. Therefore, thistechnology is not retained.

Yes

No




For Groundwater


Collection/ExtractionVertical Extraction Wells Install pumping wells to extract and collect

groundwater.

Interceptor Trench

Discharge after Treatment

Excavate a trench and install a drain to collectgroundwater for extraction. May be possible to installvia directional drilling.

As part of a collection/extraction remedy, treatmentwould be required via one of the technologies listedunder "Ex Situ Groundwater Treatment". Treatedgroundwater could potentially be discharged on-Site tothe subsurface or off-Site to a receptor such as thesanitary sewer.

Groundwater, pumping would likely result indisturbance of third party plumes to the northand/or west qf the plume originating from theSite. Prolonged pumping would likely result inwithdrawal of groundwater impacted by thirdparties. However, this technology is retainedto further evaluate the potential for impacts tothird party plumes.

See discussion under Vertical ExtractionWells.

Yes

Yes

Yes

Ex Situ Groundwater TreatmentAir Stripping

Steam Stripping with Vapor PhaseExtraction

Pass contaminated groundwater through packedcolumn aeration system to transfer VOCs from water tovapor phase.

Extracted groundwater is distributed into the top of a"packed tower" filled with a high-surface area porousmaterial (e.g., layers of plastic balls) across which isblown a countercurrent of clean steam. Dischargedsteam with contaminants is collected, condensed andtreated further.

Proven to be effective on VOCs. May requireoff-gas treatment.

Designed for contaminant concentrations 100ppm up to 10% of solution. Therefore, thistechnology is not retained.

Yes

No




For Groundwater


Carbon Adsorption Pass contaminated groundwater through a column ofgranular activated carbon so that contaminants adsorbto carbon surface.

Not effective for removal of vinyl chloride No

Ultraviolet/Oxidation

Metal-Enhanced ReductiveDehalogenation

Reverse Osmosis

Oxidize VOCs in a reactor using ultraviolet light andoxidizing agents.

Uses an electrochemical process involving oxidation ofiron and reductive dehalogenation of halogenatedVOCs in aqueous media. Ex-situ process is conductedin a reactor. This technology can also be implementedin-situ as a permeable reactive wall or "funnel andgate" system.

In reverse osmosis, water is forced through permeablemembranes that preferentially adsorb volatile organiccompounds (VOCs) from contaminated water. Thewater containing the contaminants that were not able topass through the membrane is recirculated for furthertreatment, where the organic vapors are extracted byvacuum, condensed and vented downstream of thecondenser, thus minimizing air releases.

Effective reduction of toxicity, mobility andvolume of dissolved phase VOCs. However,contaminant levels may not be high enough tobe effective.

Process destroys hazardous substances on-siterather than transferring them to anothermedium. Reaction rates are often faster thanother technologies.

This is an innovative technology. Availableinformation indicates the reaction slows overtime, resulting in exceedances of performancecriteria. Due to the uncertainty associated withthis technology, it is not retained.

Separation technologies are typically used aspre- or post-treatment processes. Furthertreatment is required for the concentrate.Therefore, this technology is not retained.

Yes

No

No




For Groundwater


Liquid/Liquid Extraction Liquid-liquid extraction involves the separation ofVOCs by contact with another liquid (solvent) in whichthe VOCs are more soluble.

VOC gaseous emissions may occur from theextraction unit requiring off-gas treatment. Inaddition, treatment (distillation) of streamsleaving the extraction unit is generallyrequired. Because a treatment train involvingother processes listed within this document -which could function independently - wouldbe necessary, this technology is not retained.

No

Microfiltration Microfiltration occurs when particles are separated byforcing fluid through a semipermeable membrane.Only the particles whose size are smaller than theopenings of the membrane are allowed to flow through.

Separation technologies are typically used aspre- or post-treatment processes. Furthertreatment is required for the concentrate.Therefore, this technology is not retained.

No



7.0 SCREENING OF REMEDIAL ALTERNATIVES

In this Section, remedial alternatives assembled from the retained technologies are described andscreened against the short- and long-term aspects of the following three criteria:

Effectiveness - This criterion focuses on the degree to which an alternative reduces toxicity,mobility, or volume through treatment, minimizes residual risks and affords long-termprotection, complies with ARARs, minimizes short-term impacts, and how quickly it achievesprotection.

Implementability - This criterion focuses on the technical feasibility and availability of thetechnologies each alternative would employ and the administrative feasibility of implementingthe alternative.

Cost - This criterion focuses on the costs of construction and any long-term cost to operate andmaintain the alternative. Costs that are grossly excessive compared to the overall effectiveness ofthe alternative may be considered as one of several factors used to eliminate alternatives. In thissection, low, moderate and high, refer to a relative measure of actual cost.

7.1 Waste Quantities

7.1.1 Soils

The waste materials considered for remedial action at the Site include soils containingconcentrations of COCs posing a potential source for groundwater contamination. Contaminatedsoils do not pose a health risk above a level of concern either through direct contact or throughthe inhalation of COC vapors originating from contaminated soils and collecting in ahypothetical future on-Site structure.

In the absence of Site-specific leaching tests on unsaturated zone soils, Soil Screening Guidance(Technical Background Document, EPA, 1996a) was used to conservatively identify the TCEconcentration in soils that may constitute a source for groundwater contamination. The defaultvalue is 60 ug/kg (based on a 20-fold dilution/attenuation factor).

Using this default value and the measured TCE concentration in Site soils, a soil waste volumeof 21,350 cubic feet was estimated. Calculations supporting this estimate are found in AppendixK of the RI Report.

7.1.2 Groundwater

Contaminated groundwater occurs on- and off-Site at concentrations exceeding MCLs and risk-based concentrations (where there is no MCL). The aerial extent of groundwater contaminatedabove these concentration thresholds is illustrated on Figure 2-22.


7.2 Remedial Alternatives

This Section describes the remedial alternatives considered for the Site and screens them foreffectiveness, implementability and cost. The alternatives are screened against the first twocriteria independently. The alternatives are screened against the last criterion relative to eachother. The following remedial alternatives were developed for the Site.

7.2.1 Alternative 1 - No Action

The No-Action Alternative leaves soil and groundwater in its current condition. The air spargingsystem currently operated on-Site would be abandoned. This alternative is considered as abaseline for comparison of other alternatives.

Effectiveness: This alternative would ultimately achieve remedial action objectives for soil andgrpundwater through natural processes. Current soil conditions are protective of human healthand the environment (direct ingestion and vapor inhalation exposure pathways) except as apotential source of groundwater contamination. Based on groundwater modeling conductedduring the RI, the current extent and magnitude of groundwater contamination is larger than thefuture scenario, even under the No-Action Alternative. Therefore, groundwater conditions wouldimprove over time as a result of natural attenuation mechanisms, ultimately achieving RAOs.However, without an 1C restricting on- and off-Site groundwater use, this alternative is noteffective in protecting human health. Institutional controls are administrative and local coderestrictions to minimize human exposure to Site contaminants. As a result, the effectiveness ofthis alternative is considered to be low.

Implementability: Implementation of this alternative requires no action and so implementabilityis ranked high.

Cost: There will be no costs associated with this alternative. Therefore, this alternative ranks lowin cost.

Alternative 1 is retained for detailed and comparative analysis.

7.2.2 Alternative 2 - Monitored Natural Attenuation (MNA) w/Institutional Controls

This alternative allows naturally occurring processes (e.g., dispersion, adsorption, biological andchemical reactions) to reduce contaminant levels. Scheduled groundwater monitoring would berequired to ensure contaminant degradation is occurring in the aquifer. Groundwater monitoringwould continue until MCLs are achieved for the COCs. In addition, an 1C restricting on- and off-Site groundwater use would be implemented.

The existing wells, installed during the RI, would be sufficient for long-term water qualitymonitoring, with the exception of the southern boundary of the Site where additional monitoringpoints may be required.

This alternative may be implemented in combination with contaminant source controltechnologies discussed under Alternatives 3 through 6.

W.S. Hatch Co. 7-2 HDR Engineering, Inc.Focused Feasibility Study Final Report . July 2004

Effectiveness: The criteria for effectiveness evaluation of MNA are very specific and aredescribed in US EPA Office of Solid Waste and Emergency Response Directive 9200.4-17P(April 1999).

These include consideration of the following:

Source mass.Groundwater flow conditions.Contaminant partitioning between soil, groundwater and soil gas.Rates of biological and non-biological contaminant transformations.

The Directive further requires these variables be validated through analytical or numericalsimulations with estimates provided for time frames to achieve RAOs. The Draft RI Reportaddressed each of these requirements. Further discussion regarding the suitability of an MNAremedy at the Site is presented in a technical memorandum provided in Appendix A.

In general, this alternative would be effective in protecting human health through the use of an1C to minimize human exposure to contaminated groundwater until RAOs are met. Groundwaterand soil RAOs would be achieved through natural attenuation mechanisms documented at theSite. Groundwater and soils data collected during the RI reveals TCE degradation products suchas DCE and VC. These daughter products indicate active degradation of the parent chemicals(PCE and TCE). Reduction in contaminant toxicity, mobility and volume would be achievedthrough natural attenuation mechanisms. The effectiveness of this alternative is considered to bemoderate.

Implementability: Implementation of this alternative potentially involves installation ofadditional monitoring wells with periodic sampling and laboratory analysis of groundwater.These remedy elements are easily implemented. The local municipality or other governmentagency would enforce an 1C. The implementability of this alternative is considered to be high.

Cost: The capital costs for this alternative are minimal, and are related to the potentialinstallation of additional monitoring wells. Operation and maintenance (O&M) costs are alsolow. The overall cost of this alternative is considered to be low.


7.2.3 Alternative 3 - Surface Capping w/Institutional Controls

This alternative would involve installing a low-permeability barrier over the area of the Site thatcontains contaminated soils. Installation of a low-permeability barrier would minimizeinfiltration of precipitation or irrigation water through the contaminated soils and subsequently togroundwater. A threshold concentration of 60 ug/Kg of TCE was used to delineate the area overwhich the barrier would be installed (Figure 7-1). The actual threshold clean-up goal would befinalized prior to remedy selection. Cap materials may include geomembrane, compacted clay,concrete, asphalt, or some combination of these. In addition, an 1C restricting on- and off-Sitegroundwater use would be implemented.


A geomembrane cap liner system with the following elements (from bottom to top) was assumedfor costing purposes.

• A 16-ounce non-woven, needle punched polypropylene geotextile (or a 4-inch thick sandcushion) to provide puncture resistance for the overlying geomembrane.

• A 60-mil low density polyethylene (LDPE) flexible geomembrane.

• A geocomposite to drain infiltrating precipitation off of the cap and to protect thegeomembrane from surface loads.

• A 1-foot thick protective cover layer.

This conceptual cap liner system design is illustrated on Figure 7-2.

Effectiveness: The low-permeability barrier would effectively minimize contaminant transportfrom the vadose zone to the water table due to infiltrating precipitation. Contaminant mobilitywould be lessened in the short-term through the reduction in infiltrating precipitation.Contaminant toxicity, mobility and volume would be reduced in the long-term through naturalattenuation mechanisms including degradation of vadose zone contamination in-situ. An 1Crestricting on- and off-Site groundwater use would minimize the likelihood of human health riskabove a level of concern until RAOs are achieved. The effectiveness of this alternative isconsidered to be moderate.

Implementability: The technology and materials needed to construct the remedy are readilyavailable. Periodic sampling and laboratory analysis of groundwater would be required. Thelocal municipality or other government agency would enforce the 1C. The implementability ofthis alternative is considered to be high.

Cost: The capital costs for this alternative are moderate, with relatively low O&M costs. Theoverall cost of this alternative is considered to be moderate.


7.2.4 Alternative 4 - Soil Vapor Extraction w/Institutional Controls

This alternative would involve construction of a soil vapor extraction system to removecontaminants from vadose zone soils. The system would require multiple vertical soil gasrecovery wells or several lengths of slotted pipe installed horizontally in the targeted treatmentzone (Figure 7-3). A vacuum would be applied to the collection system and the off-gasdischarged directly to the atmosphere. Volatile organic compound emissions to the atmospherewould be controlled through the use of a clean-air intake or other engineering control to ensurecompliance with de-minimis emission limits for a Utah Small Source Exemption. In addition, an1C restricting on- and off-Site groundwater use would be implemented.

Effectiveness: The effectiveness of this alternative is unknown due to low contaminantconcentrations in subsurface soils. Site conditions such as moisture content, organic content, andair permeability of the soil also affect system effectiveness. A pilot test would be required to


assess effectiveness of this alternative and to provide information necessary for design of a full-scale system. This alternative would likely achieve soil and groundwater RAOs more quicklythan alternatives that do not involve active remediation of subsurface soils or groundwater.Contaminant mobility may be increased as recovered soil gas would be discharged withouttreatment. Otherwise, contaminant toxicity, mobility and volume in groundwater may also bereduced through natural attenuation processes. Institutional controls would minimize thelikelihood of human health risk above a level of concern. If pilot testing proved the technology tobe viable, this alternative would be considered moderately effective.

Implementability: The technology and materials needed to construct the remedy are readilyavailable. However, the need to maintain a large remediation system in the center of the Site maypreclude Site redevelopment. The local municipality or other government agency would enforcean 1C. The implementability of this alternative is considered to be moderate.

Cost: The capital costs for this alternative are moderate, with moderate O&M costs. The overallcost of this alternative is considered to be moderate..


7.2.5 Alternative 5 - Excavation w/Off-Site Disposal, Institutional Controls

This alternative involves excavation of contaminated vadose zone soils and disposal in an off-Site facility. As discussed in the RI, subsurface soil contamination occurs primarily in a layerbetween one and three-feet thick at a depth of approximately 20-feet in the central southernportion of the Site.(locally as shallow as 9-feet). The inferred areal extent of this contaminationis illustrated on Figure 7-1. In addition, an 1C restricting on- and off-Site groundwater use wouldbe implemented.

Effectiveness: Soil RAOs would be met upon completion of remedial construction. GroundwaterRAOs would be met through natural attenuation processes necessary to remove the existingplume of impacted groundwater and any contaminants adsorbed to the aquifer matrix. Therewould be no overall reduction in contaminant toxicity or volume in soils given this remedyinvolves simply transferring the contaminants from one location to another. However, areduction in contaminant toxicity or volume would be achieved on-Site. Contaminant mobilitymay be reduced through disposal in a lined facility. Contaminant toxicity, mobility and volumein groundwater would be reduced through natural attenuation mechanisms. Institutional controlswould minimize the likelihood of human health risk above a level of concern. The effectivenessof this alternative is considered moderate.

Implementability: This alternative is technically and administratively implementable. However,the need to remove a vast quantity of overburden soils to access a relatively thin and potentiallydiscontinuous layer containing low-levels of contamination renders this alternative ofquestionable value. The presence of listed Resource Conservation and Recovery Act (RCRA)wastes in soils proposed for off-Site disposal may require disposal in a RCRA Subtitle C facility.The local municipality or other government agency would enforce an 1C. The implementabilityof this alternative is considered to be low.


Cost: The capital costs for this alternative are very high compared to the other alternatives.Excavation, backfilling and compaction of over 14,000 cubic yards of soil (assuming 1:1 sideslopes) under OSHA requirements for hazardous waste sites would be prohibitive. Additionalcosts would be incurred for air monitoring, nuisance odor control, waste soil characterization,transportation and disposal. Soil disposal costs may be excessive if the presence of RCRA listedwastes drive disposal in a hazardous waste landfill.

Alternative 5 is not retained for detailed and comparative analysis.

7.2.6 Alternative 6 -In-Situ Biological/Chemical Remediation w/Institutional Controls

This alternative involves treating the aquifer under the inferred source area (Figure 7-1) toaccelerate the reduction in COC concentrations in Site groundwater and to minimize off-Sitemigration of contaminated groundwater. Under this alternative an additive (electron donor suchas such a hydrogen source) would be injected into the aquifer to stimulate bacterial metabolismand cometabolism of contaminants. In addition, an 1C restricting on- and off-Site groundwateruse would be implemented.

Effectiveness: This technology has been demonstrated to be effective on chlorinated solvents atsome sites. However, it is considered innovative and Site-specific conditions such as aquiferheterogeneity may decrease its effectiveness. This alternative is expected to achieve RAOs inoff-Site areas more quickly than alternatives that do not involve active groundwater remediation.Remedial action objectives for vadose zone soils would be achieved through natural attenuationprocesses. Institutional controls would minimize the likelihood of human health risk above alevel of concern until RAOs have been achieved. Due to the innovative nature of the technologyused in this alternative and the heterogeneity of the aquifer, the effectiveness of this alternative isconsidered to be moderate.

Implementability: This alternative is administratively and technically implementable. The localmunicipality or other government agency would enforce an 1C. The implementability of thisalternative is considered to be high.

Cost: The capital cost for this alternative is high, with moderate O&M costs. The overall cost forthis alternative is considered to be high.


7.2.7 Alternative 7 - Groundwater Extraction w/Above Ground Treatment, InstitutionalControls

This alternative involves establishing hydraulic capture of the on-Site groundwater contaminantplume without adversely affecting the petroleum plume inferred to originate off-Site to the north(Figure 2-20). Hydraulic capture of the contaminant plume would be achieved through theinstallation of a single pumping well. Groundwater would be extracted with a submersibleelectric pump, treated on-Site and discharged to surface water via storm sewer. Discharge ofuntreated groundwater to the Publicly Owned Treatment Works (POTW) is also considered. TheSouth Davis Sewer District (the District) Facility is the POTW serving the Site.


Effectiveness: The effectiveness of this alternative depends on establishing hydraulic capture ofthe groundwater contaminant plume as close to the downgradient property boundary as possiblewithout affecting the adjacent off-Site contaminant plume inferred to exist to the north of theSite. Groundwater modeling indicates hydraulic capture may be possible with a single well.pumping between 0.15 and 6 gpm (using the range of hydraulic conductivities measured duringthe RI). However, hydraulic capture may not be possible without some adverse effects on theplume inferred to adjoin the Site to the north (see additional discussion in Section 8.3.6).

The groundwater extraction and treatment technologies are proven, and discharge to the localPOTW would allow effective treatment at an off-Site facility. If hydraulic capture can beestablished, this alternative would achieve RAOs in off-Site areas more quickly than alternativesthat do not involve active groundwater remediation. Remedial action objectives for off-Sitegroundwater and on-Site vadose zone soils would be achieved through natural attenuationprocesses.

Contaminant toxicity, mobility and volume would be reduced under this alternative throughtreatment of groundwater and through natural attenuation mechanisms. An 1C restricting on- andoff-Site groundwater use would minimize the likelihood of human health risks above a level ofconcern until RAOs have been achieved. The effectiveness of this alternative is considered to behigh if it is technically implementable.

Implementability: The technology and materials needed to construct the remedy are readilyavailable. The local municipality or other government agency would enforce an 1C. Theimplementability of this alternative is considered to be moderate given the potential for adverseeffects on the inferred contaminant plume to the north. Adverse effects may include changing thedirection of plume migration and size.

Cost: The capital and O&M costs for each treatment option are discussed further under thefollowing subheadings:

• Alternative 7a - Treatment via Air Stripping - This alternative involves treatment via airstripping. The extracted groundwater is pumped to the top of a packed column (orequivalent) air stripper and allowed to cascade over packing designed to distribute thecontaminated groundwater into a thin film. Air is blown up through the column oppositeto the flow of water. Contaminants dissolved in the water partition into the air stream andare discharged to the atmosphere. Relative capital and O&M costs of this alternative arehigh. Therefore, overall cost is ranked high.

• Alternative 7b - Treatment via Ultraviolet Oxidation - This alternative involvestreatment of extracted groundwater via ultraviolet (UV) oxidation. Ultraviolet oxidationis a destruction process that oxidizes organic constituents in wastewater by the additionof strong oxidizers and irradiation with UV light (Figure 7-4). Typically, easily oxidizedorganic compounds (such as PCE, TCE and VC) are rapidly destroyed in theUV/oxidation processes. Relative capital and O&M costs of this alternative are high.Therefore, overall cost is ranked high.

• Alternative 7c - Discharge to POTW - This alternative involves discharge of untreatedgroundwater to the South Davis Sewer District Facility. Extracted groundwater would be


conveyed via pipe to a point within the District's system. This alternative has moderatecapital costs and low O&M costs. A fee associated with water treatment would benegotiated with the District. The overall relative cost of Alternative 1C is rankedmoderate.

All variations on Alternative 7 are retained for detailed and comparative analysis.

Table 7-1 summarizes the screening of alternatives and identifies those alternatives that havebeen retained and those that have been rejected. The justification for retaining or rejecting analternative is also provided in the table.

TABLE 7-1Screening of Alternatives

RemedialAlternative

1 - No Action

2 - MNA w/ICs

3 - Surface Cappingw/ICs

4 - Soil VaporExtraction w/ICs

5 - Excavationw/Off-Site Disposal,ICs

6 - In-SituBioremediationw/ICs

7 a - Ground waterExtraction w/AirStripping, ICs

7b - GroundwaterExtraction w/UV-Oxidation, ICs

7c - GroundwaterExtractionw/Discharge toPOTW, ICs

Effectiveness

Low - no remedialactionModerate - naturaldegradation evidenton- and off-SiteModerate -minimizes infiltrationand contaminantmigration togroundwaterUnknown - pilottesting required

Moderate -contaminated soilremoved

Moderate -innovative; Siteconditions not ideal.

High - proventechnology



Implementability

High - requires noactionHigh - numerousmonitoring wells inexistenceHigh - easilyconstructed

Moderate - easilyconstructed; mayinterfere with SitedevelopmentLow - large volumeof overburden soil;possible LDRissues.High - easilyconstructed

Moderate -commingled plumes



Relative Cost

Low - requires noactionLow - low capitaland O&M costs

Moderate -moderate capitalcosts; low O&Mcosts

Moderate -moderate capitalcosts; high O&McostsHigh - highcapital costs; lowO&M costs

High - highcapital costs;moderate O&McostsHigh - highcapital costs;moderate O&McostsHigh - highcapital costs;moderate O&McostsModerate -moderate capitalcosts; moderateO&M costs

Retained orRejected

Retained asbaselineRetained

Retained

Retained

Rejected - lowimplementabilityand high cost.

Retained

Retained

Retained

Retained



8.0 DETAILED ANALYSIS OF ALTERNATIVES

8.1 Introduction

The detailed analysis is conducted on the limited number of alternatives that represent viableapproaches to remedial action after the screening stage. This analysis consists of an assessmentof individual alternatives against each of nine evaluation criteria.

8.2 Evaluation Criteria

The nine NCP criteria are described below.

NCP Criteria:

1. Overall protection of human health and the environment. . ........ .... .Alternatives shall be assessed to determine whether they can adequately protecthuman health and the environment, in both the short- and long-term, fromunacceptable risks posed by hazardous substances, pollutants, or contaminantspresent at the site by eliminating, reducing, or controlling human and ecologicalexposures.

2. Compliance with ARARs.The alternatives shall be assessed to determine whether they attain applicable orrelevant and appropriate requirements under federal environmental laws and stateenvironmental or facility siting laws or provide grounds for invoking waivers.

There are no location-specific ARARs, as discussed in Section 5.0. The remedialalternatives are evaluated against the following potential chemical- and action-specific ARARs:


• National Primary and Secondary Drinking Water Standards

• Utah Primary Drinking Water Standards

• Utah Groundwater Quality Standards

• Utah Alternate Corrective Action Concentration Limits

• Utah Corrective Action Clean-up Standards at UST and CERCLA sites


• Clean Water Act Ambient Water Quality Criteria

• National Pollutant Discharge Elimination System (NPDES)

• National Underground Injection Control Regulations

• National Guidelines establishing Test Procedures for the Analysis of Pollutants


• Utah Well Drilling and Completion Standards

• Utah Small Source Exemption de-minimis emissions

• Utah Discharges to Surface Water (UPDES)

• Utah Underground Injection Control

• Utah Fugitive Dust Control

3. Long-term effectiveness and permanence.

Alternatives shall be assessed for the long-term effectiveness and permanence theyafford, along with the degree of certainty that the alternative will prove successful.Factors that shall be considered, where appropriate, include the following:

• Magnitude of residual risk remaining from untreated waste or treatmentresiduals remaining at the conclusion of the remedial activities.

• Adequacy and reliability of controls such as containment systems andinstitutional controls that are necessary to manage treatment residuals anduntreated waste.

4. Reduction oftoxicity, mobility or volume through treatment.

Alternatives shall be assessed for the degree to which they employ recycling or treatmentthat reduces toxicity, mobility, or volume, including how treatment is used to address theprincipal threats posed by the site.

5. Short-term effectiveness.

The short-term impacts of alternatives shall be assessed considering the following:

• Short-term risks that might be posed to the community during implementationof an alternative;

• Potential impacts on workers during remedial action and the effectiveness andreliability of protective measures;

• Potential environmental impacts of the remedial action and the effectivenessand reliability of mitigative measures during implementation; and

• Time until protection is achieved.

6. Implementability.

The ease or difficulty of implementing the alternatives shall be assessed by consideringthe following types of factors as appropriate:

• Technical feasibility, including technical difficulties and unknowns associatedwith the construction and operation of a technology, the reliability of the


technology, ease of undertaking additional remedial actions, and the ability tomonitor the effectiveness of the remedy.

• Administrative feasibility, including activities needed to be coordinate withother offices and agencies and the ability and time required to obtain anynecessary approval and permits from other agencies (for off-Site actions).

• Availability of services and materials, including the availability of adequateoff-Site treatment, storage capacity, and disposal capacity and services; theavailability of necessary equipment and specialists, and provisions to ensureany necessary additional resources; the availability of services and materials;and availability of prospective technologies.

7. Cost.

The types of costs that shall be assessed include the following: ~

• Capital costs, including both direct and indirect costs;

• Annual operations and maintenance costs; and

• Net present value of capital and O&M costs.

EPA guidance (EPA, 2000) requires the use of a 1% discount factor when calculating netpresent value of capital, operation and maintenance costs for all non-federal facilities.The Site is not a federal facility and so the 1% discount rate is used.

8. State acceptance.

Assessment of state concerns may not be completed until comments on the FFS arereceived but may be discussed to the extent possible in the proposed plan issued forpublic comment. The state concerns that shall be assessed include the following:

• The state's position and key concerns related to the preferred alternative andother alternatives; and

• State comments on ARARs or the proposed use of waivers.

9. Community acceptance.

This assessment includes determining which components of the alternatives interestedpersons in the community, including local elected officials, support, have reservationsabout, or oppose. This assessment may not be completed until comments on the proposedplan are received.

W.S. Hatch Co. 8-3 HDR Engineering, Inc.Focused Feasibility Study Final Report . • July 2004

8.3 Detailed Analysis of Remedial Alternatives

This section provides the detailed analysis of the retained remedial alternatives including:

• Alternative 1 - No Further Action

• Alternative 2 - Monitored Natural Attenuation (MNA) w/Institutional Controls

• Alternative 3 - Surface Capping w/Institutional Controls

• Alternative 4 - Soil Vapor Extraction w/Institutional Controls

• Alternative 6 - Property Boundary In-Situ Biological/Chemical Remediationw/Institutional Controls

• Alternative 7 - Groundwater Extraction w/Above Ground Treatment, InstitutionalControls

8.3.1 Alternative 1 - No Further Action

The No-Action Alternative leaves soil and groundwater in its current condition. The air spargingsystem currently operated on-Site would be abandoned. This alternative is considered as abaseline for comparison of other alternatives.

Overall Protection of Human Health and Environment - This alternative would ultimatelyachieve RAOs for vadose zone soil and groundwater through natural processes. Current soilconditions are protective of human health and the environment (direct ingestion and vaporinhalation exposure pathways) except as a potential source of groundwater contamination.Contaminant fate and transport modeling conducted during the RI predicts that RAOs will bemet in off-Site areas between 2022 and 2057 (see Section 2.3). However, without an 1Crestricting on- and off-Site groundwater use, this alternative may not be effective in protectinghuman health.

Compliance with ARARs - ARARs are discussed in Sections 5.0 and 8.2. There are no location-specific ARARs. Since no action would be taken under this alternative, action-specific ARARsdo not apply. The following summarizes the chemical-specific ARARs for the alternative.


• National Primary and Secondary Drinking Water Standards, Utah Primary DrinkingWater, Corrective Action Clean-up Standards, Alternate Corrective Action ConcentrationLimits and Groundwater Quality Standards - Contaminant fate and transport modelingpredicts that these ARARs will be met in off-Site areas between 2022 and 2057.

Long-Term Effectiveness - Some potential human health risk associated with possible futuregroundwater use will remain until RAOs are achieved. The No-Action Alternative offers a highlevel of permanence once RAOs are achieved through natural processes.

Reduction in Toxicity, Mobility, and Volume through Treatment - There is no reduction intoxicity, mobility and volume under the No Action Alternative other than that achieved through

W.S. Hatch Co. ' 8-4 HDR Engineering, Inc.Focused Feasibility Study Final Report . July 2004

natural attenuation processes (see Alternative 2- Monitored Natural Attenuation (MNA)w/Institutional Controls)

Short-Term Effectiveness - The short-term effectiveness would remain unchanged under thisalternative.

Implementability - Implementation of the No-Action alternative would require no effort.

Cost - There are no costs associated with the No-Action Alternative.

State Acceptance - State acceptance will be determined after the public comment period andproposed plan.

Community Acceptance - Community acceptance will be determined after the public commentperiod and proposed plan.

8.3.2 Alternative 2 - Monitored Natural Attenuation (MNA) w/Institutional Controls

This alternative allows naturally occurring processes (e.g., dispersion, adsorption, biological andchemical reactions) to reduce contaminant levels. Scheduled groundwater monitoring would berequired to ensure contaminant degradation is occurring in the aquifer and would continue untilMCLs were achieved for the COCs. In addition, an 1C restricting on- and off-Site groundwateruse would be implemented.

The existing wells, installed during the RI, would be sufficient for long-term water qualitymonitoring, with the exception of the southern boundary of the Site where additional monitoringpoints may be required.

Alternative 2 consists of the following elements:

• An 1C restricting on- and off-Site groundwater use.

• Long-term water quality monitoring on- and off-Site.

Overall Protection of Human Health and Environment - This alternative would achieve remedialaction objectives for vadose zone soil and groundwater through natural processes. Current soilconditions are protective of human health and the environment (direct ingestion and vaporinhalation exposure pathways) except as a potential source of groundwater contamination.Contaminant fate and transport modeling predicts that RAOs will be met in off-Site areasbetween 2022 and 2057 (see Section 2.3). Restrictions on groundwater use until RAOs are metwill minimize the potential for human health effects above a level of concern.

Compliance with ARARs - ARARs are discussed in Section 5.0. There are no location-specificARARs. The following summarizes the chemical- and action-specific ARARs for thisalternative.

W.S. Hatch Co. 8-5 HDR Engineering, Inc.Focused Feasibility Study Final Report " July 2004


• National Primary and Secondary Drinking Water Standards, Utah Primary DrinkingWater, Corrective Action Clean-up Standards, Alternate Corrective Action ConcentrationLimits and Groundwater Quality Standards - Contaminant fate and transport modelingpredicts that these ARARs will be met in off-Site areas between 2022 and 2057.


• Clean Water Act Ambient Water Quality Criteria, National Pollutant DischargeElimination System (NPDES), and Utah Discharges to Surface Water (UPDES) - Surfacewater discharge is not part of this alternative.

• National Underground Injection Control Regulations - Underground injection is not partof this alternative.

• National Guidelines establishing Test Procedures for the Analysis of Pollutants - Effluentdischarge is not part of this alternative.

• Utah Well Drilling and Completion Standards - New monitoring wells (if necessary) willbe installed in accordance with these standards.

• Utah Small Source Exemption de-minimis emissions - Air emissions are not part of thisalternative.

• Utah Underground Injection Control - Underground injection is not part of thisalternative.

• Utah Fugitive Dust Control - Earthwork is not part of this alternative.

Long-Term Effectiveness - The criteria for effectiveness evaluation of MNA are very specific andare described in US EPA Office of Solid Waste and Emergency Response Directive 9200.4-17P(April, 1999). These include consideration of the following:

Source mass.Groundwater flow conditions.Contaminant partitioning between soil, groundwater and soil gas.Rates of biological and non-biological contaminant transformations.

The Directive further requires these variables be validated through analytical or numericalsimulations with estimates provided for time frames to achieve RAOs. The Draft RI Reportaddressed each of these requirements. Further discussion regarding the suitability of an MNAremedy at the Site is presented in a technical memorandum provided in Appendix A.

In general, this alternative would be effective in protecting human health through the use of an1C to minimize human exposure to contaminated groundwater until RAOs are met. In addition,this alternative offers a high degree of permanence once RAOs are met through naturalprocesses. The adequacy and reliability of an 1C is a function of the effectiveness of theenforcement agency. The local municipality would be the enforcement agency.


Reduction in Toxicity, Mobility, and Volume through Treatment - Natural degradation of some ofthe COCs (PCE and TCE) results in one intermediate decay product (VC) with a higher toxicitythan the parent chemical. However, the ultimate decay products are non-toxic. Therefore, thisalternative will result in a reduction in contaminant toxicity. Reduction in contaminant, mobilityand volume would be achieved through natural attenuation mechanisms.

Short-Term Effectiveness - The short-term effectiveness would remain unchanged under thisalternative.

Implementability - These remedy elements are easily implemented. The local municipality orother government agency would enforce the 1C.

Cost - The capital costs for this alternative are minimal, and are related to the potentialinstallation of additional monitoring wells. Operation and maintenance costs are also low andwould involve scheduled sampling and analyses of groundwater. The 30-year present worth cost

Tor implementing the alternative (based on a 7 percent discount rate) is $67,698. Detailed costingis presented in Appendix B.



8.3.3 Alternative 3 - Surface Capping w/Institutional Controls

This alternative would involve installing a low-permeability barrier over the area of the Site thatcontains contaminated soils. A low-permeability barrier would minimize infiltration ofprecipitation or irrigation water through contaminated soils and subsequently to groundwater. Athreshold concentration of 60 ug/kg of TCE was used to delineate the area over which the barrierwould be installed (Figures 7-1 and 7-2). Cap materials may include a building footprint,geomembrane, compacted clay, concrete, asphalt, or some combination of these. In addition, an1C restricting on- and off-Site groundwater use would be implemented.


• Low-permeability barrier over contaminated subsurface soils.


• Long-term water quality monitoring.

Overall Protection of Human Health and Environment - This alternative would achieve RAOsfor vadose zone soil and groundwater through natural processes. Current soil conditions areprotective of human health and the environment (direct ingestion and vapor inhalation exposurepathways) except as a potential source of groundwater contamination. Capping of contaminatedsoils would reduce the amount of COCs leaching to groundwater allowing natural degradationprocesses to destroy the COCs remaining in the soils. The reduction in transport of COCs fromsoils to groundwater would reduce the amount of time for RAOs to be met in groundwater.

W.S. Hatch Co. 8-7 HDR Engineering, Inc.Focused Feasibility Study Final Report . . July 2004

Contaminant fate and transport modeling predicts that ARARs will be met in off-Site areas underAlternatives 1 and 2 between 2022 and 2057. Use of a cap over source material underAlternative 3 may accelerate the achievement of ARARs by reducing the amount of COCstransported from the vadose zone to the water table. The degree of acceleration has not beenquantified. Restrictions on groundwater use until RAOs are met would minimize the potential forhuman health effects above a level of concern.



• National Primary and Secondary Drinking Water Standards, Utah Primary DrinkingWater, Corrective Action Clean-up Standards, Alternate Corrective Action ConcentrationLimits and Groundwater Quality Standards - Contaminant fate and transport modelingpredicts that ARARs will be met in off-Site areas under Alternatives 1 and 2 between2022 and 2057. Use of a cap over source material under Alternative 3 may accelerate theachievement of ARARs by reducing the amount of COCs transported from the vadosezone to the water table. The degree of acceleration has not been quantified.




- • National Guidelines establishing Test Procedures for the Analysis of Pollutants - Effluentdischarge is not part of this alternative.


• Utah Small Source Exemption de-minimis emissions - Air emissions are not part of thisalternative.


• Utah Fugitive Dust Control - Earthwork will comply with National Ambient Air QualityStandards.

Long-Term Effectiveness - This alternative would be effective in protecting human healththrough the use of an 1C restricting on- and off-Site groundwater until groundwater and soilRAOs are met. In addition, this alternative offers a high degree of permanence once RAOs aremet through natural processes. However, the degree to which this alternative accelerates theotherwise natural restoration of groundwater is unknown. The adequacy and reliability of an 1C


is a function of the effectiveness of the enforcement agency. The local municipality would be theenforcement agency.

Reduction in Toxicity, Mobility, and Volume through Treatment - Natural degradation of some ofthe COCs (PCE and TCE) results in one intermediate decay product (VC) with a higher toxicitythan the parent chemical. However, the ultimate decay products are non-toxic. Therefore, thisalternative will result in a reduction in contaminant toxicity. Contaminant mobility would belessened in the short-term through the reduction in infiltrating precipitation. Reduction incontaminant volume would be achieved through natural attenuation mechanisms

Short-Term Effectiveness - COCs are not present in surface soils in significant concentrations.Therefore, soil grading and barrier installation would not generate significant emissions of COCscreating little short-term risk.

Implementability - The technology and materials needed to construct the remedy are readilyavailable. The local municipality or other government agency would enforce an 1C.

Cost - The capital costs for this alternative include installation of a low-permeability barrier andthe potential installation of additional monitoring wells. For the purpose of developing a costestimate, geomembrane is used as the low permeability barrier. Operation and maintenance costsare low and would involve scheduled sampling and analyses of groundwater. The 30-yearpresent worth cost for implementing the alternative (based on a 7 percent discount rate) is$147,207. Detailed costing is presented in Appendix B.



8.3.4 Alternative 4 - Soil Vapor Extraction ^/Institutional Controls

This alternative would involve construction of a soil vapor extraction (SVE) system to removecontaminants from vadose zone soils. The system would require multiple vertical soil gasrecovery wells or several lengths of slotted pipe installed horizontally in the targeted treatmentzone (Figure 7-2). A vacuum would be applied to the collection system and the off-gasdischarged directly to the atmosphere. It is assumed the SVE system would operate for fiveyears. This duration is based on best professional judgment. In addition, an 1C restricting on- andoff-Site groundwater use would be implemented.


• Soil vapor extraction wells (maximum of six vertical wells based on an assumed 50-footspacing).

• Positive displacement or impeller blower.

• Soil vapor collection manifold.

W.S. Hatch Co. 8-9 . HDR Engineering, IDC.Focused Feasibility Study Final Report July 2004



The number of SVE wells proposed under Alternative 4 is based on professional judgment inorder to form the basis for a present worth cost estimate. The actual number and placement ofSVE wells would be determined during remedial design if this alternative is selected.

Overall Protection of Human Health and Environment - This alternative would achieve remedialaction objectives for vadose zone soil and groundwater through a combination of contaminantphase transfer and natural attenuation processes. Current soil conditions are protective of humanhealth and the environment (direct ingestion and vapor inhalation exposure pathways) except asa potential source of groundwater contamination. Removal of contaminant mass from vadosezone soils would reduce the amount of contaminant that could leach to the water table, and inturn, reduce the length of time necessary to reach groundwater RAOs. Contaminant fate andtransport modeling predicts ARARs will be met in off-Site areas under Alternatives 1 and 2between 2022 and 2057. Removal of contaminant mass from the source area through SVE underAlternative 4 may accelerate the achievement of ARARs by reducing the amount of COCstransported from the vadose zone to the water table. The degree of acceleration has not beenquantified. Restrictions on groundwater use until RAOs are met will minimize the potential forhuman health effects above a level of concern.



• National Primary and Secondary Drinking Water Standards, Utah Primary DrinkingWater, Corrective Action Clean-up Standards, Alternate Corrective Action ConcentrationLimits and Groundwater Quality Standards - Contaminant fate and transport modelingpredicts ARARs will be met in off-Site areas under Alternatives 1 and 2 between 2022and 2057. Removal of contaminant mass from the source area through SVE underAlternative 4 may accelerate the achievement of ARARs by reducing the amount ofCOCs transported from the vadose zone to the water table. The degree of acceleration hasnot been quantified.

Potential Action-Specific ARARs: j .






• Utah Small Source Exemption de-minimis emissions - Air emissions of VOCs will notexceed the five-ton per year limit for de-minimis sources.



Long-Term Effectiveness - This alternative would be effective in protecting human healththrough the use of an 1C restricting on- and off-Site groundwater use to minimize humanexposure to site contaminants until groundwater and soil RAOs are met. In addition, thisalternative offers a high degree of permanence once RAOs are met. However, the degree, towhich this alternative accelerates the otherwise natural restoration of groundwater is unknown.Site conditions such as soil contaminant concentrations, moisture content, organic content, andair permeability of the soil also affect the systems effectiveness. The suspected presence of lowlevels of COCs dissolved in suspected waste oil or diesel fuel (see Section 2.2.8) may limitvolatilization of COCs into soil vapor. A pilot test would be required to assess effectiveness ofthis alternative and to provide information necessary for design of a full-scale system. Theadequacy and reliability of an 1C is a function of the effectiveness of the enforcement agency.The local municipality would be the enforcement agency.

Reduction in Toxicity, Mobility, and Volume through Treatment - Natural degradation of some ofthe COCs (PCE and TCE) results in one intermediate decay product (VC) with a higher toxicitythan the parent chemical. However, the ultimate decay products are non-toxic. Therefore, thisalternative will result in a reduction in contaminant toxicity. Contaminant mobility would beincreased by discharging recovered soil gas to the atmosphere. Reduction in contaminant volumewould be achieved through natural attenuation mechanisms.

Short-Term Effectiveness - Discharge of contaminated soil vapor to the atmosphere wouldincrease potential health risks to the surrounding community. However, compliance withdischarge limitations under the Utah Small Source Exemption would minimize the potential forhealth risks above a level of concern. Risks associated with vapor intrusion into future on-Sitestructures may be reduced through operation of an SVE system.

Implementability - The technology and materials needed to construct the remedy are readilyavailable. However, the need to maintain a large remediation system in the center of the Site maypreclude Site redevelopment. The local municipality or other government agency would enforcethe institutional control.

Cost - The cost for this alternative is based on 5-year remediation system operation followed by5-years of additional groundwater monitoring. The duration of active remediation is based onprofessional judgment. The 10-year present worth cost for implementing the alternative (basedon a 7 percent discount rate) is $158,322. Detailed costing is presented in Appendix B.




8.3.5 Alternative 6 - Enhanced In-Situ Biological/Chemical Remediation ^/InstitutionalControls

Under this alternative an additive (electron donor such as such a hydrogen source) would beinjected into the aquifer to stimulate bacterial metabolism and cometabolism of contaminants.The overall purpose of this remedial alternative would be to minimize off-Site migration ofCOCs. Two products are considered under this alternative including a proprietary hydrogenrelease compound (HRC®) and colloidal metallic iron.

Hydrogen Release Compound (HRC®) is a polylactate ester that is designed to slowly releaselactic acid when in contact with water. The lactic acid is then metabolized by subsurfacemicrobes that indirectly produce hydrogen. Hydrogen is a key ingredient in reductivedechlorination. Once in the subsurface, HRC will reside within the aquifer matrix fuelingreductive dechlorination for up to 18 months (Appendix C).

Colloidal Metallic Iron has been proven effective for in-situ reductive dechlorination viaanaerobic corrosion. Iron is preferred over other elemental metals due to its dehalogenationefficacy, cost and benign environmental impact. The chlorinated hydrocarbon adsorbs directly tothe metal's surface and reductive dehalogenation is accomplished by one or all of the followingmechanisms:

• The iron acts as a reductant by supplying electrons directly from the metal surface to theadsorbed halogenated compound.

• Metallic iron may act as a catalyst for the reaction of hydrogen with the halogenatedhydrocarbon.

• Solubilized ferrous iron can also act as a reductant.

For the purposes of costing this alternative, the additive would be injected into the shallowaquifer under the inferred potential source area (Figure 7-1). The actual treatment area as well asthe preferred additive would be finalized during remedial design should this alternative beselected. However, cost information received from vendors suggests that the HRC® productwould be more cost effective. Chemical injection would be accomplished using direct pushequipment. Typically, drive rods are pushed to the bottom of the contaminated saturated zoneand then the chemical is injected as the rods are withdrawn.

Based on manufacturers recommendations, an initial treatment would be followed by additionaltreatments every two years using no more than 50% of the previous chemical dose. Based on thisrule of thumb, a total of four treatments over the course of 10-years is assumed. An initialchemical dose of 8,400 Ibs was calculated by the supplier for HRC® (Appendix C). The actualfrequency and magnitude of treatment will depend on groundwater quality monitoring data.


Treatment with colloidal metallic iron would consist of a single treatment involving 122,000pounds (Appendix C). In addition, an 1C restricting on- and off-Site groundwater use would beimplemented.


• Initial injection of chemical additive into the aquifer under the source area (Figure 7-1).

• Repeated applications of additive every 2 years for 10 years (for HRC® only).



Overall Protection of Human Health and Environment - This alternative would achieve RAOsfor vadose zone soil through natural attenuation processes and for groundwater through enhancednatural attenuation processes. Current soil conditions are protective of human health and theenvironment (direct ingestion and vapor inhalation exposure pathways) except as a potentialsource of groundwater contamination. Accelerating the natural destruction of chlorinated COCsin the shallow aquifer under the source area would minimize off-Site migration of chlorinatedCOCs and decrease the time needed to achieve RAOs in on-Site groundwater. Contaminant fateand transport modeling predicts ARARs will be met in off-Site areas under Alternatives 1 and 2between 2022 and 2057. Removal of contaminant mass from the aquifer through enhancednatural processes under Alternative 6 may accelerate the achievement of ARARs. The degree ofacceleration has not been quantified. Restrictions on groundwater use until RAOs are met willminimize the potential for human health effects above a level of concern.

Compliance with ARARs - ARARs are discussed in Section 5.0. There are no location-specificARARs. The following summarizes the chemical- and action-specific ARARs for the alternative.


• National Primary and Secondary Drinking Water Standards, Utah Primary DrinkingWater, Corrective Action Clean-up Standards, Alternate Corrective Action ConcentrationLimits and Groundwater Quality Standards - Contaminant fate and transport modelingpredicts ARARs will be met in off-Site areas under Alternatives 1 and 2 between 2022and 2057. Removal of contaminant mass from the aquifer through enhanced naturalprocesses under Alternative 6 may accelerate the achievement of ARAR's. The degree ofacceleration has not been quantified.



• National Underground Injection Control Regulations - Injection of proprietary additivesto enhance in-place destruction of chlorinated COCs will comply with this ARAR.




• Utah Small Source Exemption de-minimis emissions - No air emissions are associatedwith this alternative.

• Utah Underground Injection Control - No permit required. However, may requirecompliance with the substantive requirements of a permit for injection of chemicaladditives.


Long-Term Effectiveness - This alternative would be effective in protecting human healththrough the use of an 1C to minimize human exposure to site contaminants until groundwater andsoil RAOs are met. In addition, this alternative offers a high degree of permanence once RAOsare met. The technology employed under this alternative has been demonstrated to be effectiveon chlorinated solvents at some sites. However, it is considered innovative and Site-specificconditions such as aquifer heterogeneity may decrease its effectiveness. The adequacy andreliability of an 1C is a function of the effectiveness of the enforcement agency. The localmunicipality would be the enforcement agency.

Reduction in Toxicity, Mobility, and Volume through Treatment - Natural degradation of some ofthe COCs (PCE and TCE) results in one intermediate decay product (vinyl chloride) with ahigher toxicity than the parent chemical. However, the ultimate decay products are non-toxic.Therefore, this alternative will result in a reduction in contaminant toxicity. Contaminantmobility and volume would be reduced through in-place destruction.

Short-Term Effectiveness - No short-term risks to workers, the community or the environmentare posed under this alternative. Protection will be achieved upon implementation of the 1Crestricting groundwater use.

Implementability - The technology and materials needed to implement the remedy are readilyavailable. The local municipality or other government agency would enforce the 1C.

Cost - The cost for this alternative is based on 10 years of remediation followed by 5 additionalyears of groundwater monitoring. The 10-year remedial duration is based on vendorrecommendations. The 30-year present worth cost for implementing the alternative (based on a 7percent discount rate) is $328,800 for the HRC® product. The initial capital costs for treatmentwith colloidal metallic iron is $545,000 (Appendix C). Therefore, detailed costing was notperformed for the colloidal metallic iron option. Detailed costing for the HRC® product ispresented in Appendix B.




8.3.6 Alternative 7 - On-Site Groundwater Extraction w/Above Ground Treatment,Institutional Controls

This alternative involves establishing hydraulic capture of the on-Site groundwater contaminantplume without adversely affecting the petroleum plume inferred to originate off-Site to the north(Figure 2-20). Hydraulic capture of the contaminant plume would be achieved through theinstallation of a single pumping well. The well would be located to the west of the inferredsource area to minimize the chance of missing any small pockets of source material.Groundwater would be extracted with a submersible electric pump, treated on-Site anddischarged to surface water via storm sewer. Discharge of untreated groundwater to the POTW isalso considered. The South Davis Sewer District Facility is the POTW serving the Site.

The hydraulic model calibrated during the RI (Hatchco, 2003) was used to optimize theextraction well location and required pumping rate needed to capture contaminated groundwaterin the shallow aquifer traversing the Site. A single well pumping between 0.15 and 6 gpm (usingthe range of hydraulic conductivity values measured at the Site) was determined by modeling toestablish hydraulic capture in the desired area with the least impact on the inferred overlappingcontaminant plume to the north. Figure 8-1 illustrates the path of individual particles in theidealized model domain under current conditions and under the influence of pumping(superimposed on the groundwater contaminant plume). A review of these two figures revealsthat pumping has a limited effect on the inferred petroleum plume to the north. The northernplume is deflected slightly to the south under the pumping condition. A summary of the particletracking exercise is provided in Appendix D.

Cost information for each treatment option was solicited from technology vendors (vendorquotes are presented in Appendix C). The estimated groundwater pumping rate was based onflow model output for a single pumping well (maximum of 6 gpm) plus a factor of safetyresulting in a design flow of 8 gpm. The treatment system influent contaminant concentrationswere based on PCE, TCE, cis-l,2-DCE and VC concentrations measured in well 3S on April 24,2002. For costing purposes, the duration of active remediation is assumed to be 15 years. Thisduration is based on professional judgment.

The design flow rate and chemistry includes:

• Pumping rate = 8 gpm

• PCE concentration = 7 ug/L

• TCE concentration = 207 ug/L

• cis-1,2 DCE concentration = 405 ug/L

• VC concentration = 72 ug/L

The feasibility of discharging untreated groundwater directly to the POTW via the sanitary sewerwas assessed through discussions with South Davis Sewer District and submittal of analytical

W.S. Hatch Co. 8-15 HDR Engineering, Inc.Focused Feasibility Study Final Report . . July 2004

and other data. The District will not accept untreated discharge (see Section 8.3.6.3 for furtherdiscussion).

The detailed analysis is performed for each of the three variations on Alternative 7.

8.3.6.1 Alternative 7a - Treatment via Air Stripping

This alternative involves treatment via air stripping. The extracted groundwater is pumped to thetop of a packed column (or equivalent) air stripper and allowed to cascade over packing designedto distribute the contaminated groundwater into a thin film. Air is blown up through the columnopposite to the flow of water. Contaminants dissolved in the water partition into the air streamand are discharged to the atmosphere. COCs will discharge to the atmosphere at a small fractionof the de-minimis levels defined by regulation. Therefore, no off-gas treatment is considered inthis alternative. Treated groundwater would be discharged to surface water via storm sewer.

For costing purposes the remediation system is sized to achieve at least 99% removal of allCOCs.

Alternative 7a consists of the following elements:

• One extraction well, electric submersible pump, piping, and controls.

• Packed column air stripper.

• Conveyance to storm sewer.



Overall Protection of Human Health and Environment - This alternative would minimize orprevent off-Site migration of COCs until RAOs are achieved. The contaminant transport modelcalibrated during the RI (Hatchco, 2003) was used to estimate the time required to achieve RAOsin the off-Site area. Assuming complete hydraulic capture is established in 2003, the contaminanttransport modeling predicted that COC concentrations decline in off-Site areas to meet RAOs by2017 (Appendix D).

Remedial action objectives for vadose zone soil will be met through natural attenuation. Currentsoil conditions are protective of human health and the environment (direct ingestion and vaporinhalation exposure pathways) except as a potential source of groundwater contamination.Restrictions on groundwater use until RAOs are met will minimize the potential for humanhealth effects above a level of concern.

Compliance with ARARs - ARARs are discussed in Section 5.0. There are no location-specificARARs. The following summarizes the chemical- and action-specific ARARs for theAlternative.



• National Primary and Secondary Drinking Water Standards, Utah Primary DrinkingWater, Corrective Action Clean-up Standards, Alternate Corrective Action ConcentrationLimits and Groundwater Quality Standards - Contaminant fate and transport modelingpredicts ARA's will be met in off-Site groundwater under Alternative 7a in 2017(Appendix D). However, permanent reduction in COCs in off-Site areas may requirecontinued operation of the remediation system beyond 2017 to prevent off-Site migrationof COCs remaining on-Site above ARARs. For costing purposes, the total remedialduration is assumed to be 15 years.


• Clean Water Act Ambient Water Quality Criteria, National Pollutant DischargeElimination System (NPDES), and Utah Discharges to Surface Water (UPDES) -Discharge of treated groundwater to surface water would comply with the requirementsof a UPDES permit.


• National Guidelines establishing Test Procedures for the Analysis of Pollutants - Effluentquality under a UPDES permit would be established through analytical testingconforming to these guidelines.


• Utah Small Source Exemption de-minimis emissions - Minimal emissions associated withthe air stripper discharge will comply with this ARAR.

• Utah Underground Injection Control - Injection is not part of this alternative.


Long-Term Effectiveness - This alternative would be effective in protecting human healththrough the use of an 1C to minimize human exposure to site contaminants until vadose zone soiland groundwater RAOs are met. Contaminant transport modeling predicts RAOs will be met inoff-Site areas by 2017 (Appendix D).

This alternative offers a high degree of permanence through the removal of COCs fromgroundwater and the natural attenuation of the COCs beyond the hydraulic capture area createdby the pumping well. The adequacy and reliability of an 1C is a function of the effectiveness ofthe enforcement agency. The local municipality would be the enforcement agency.

Reduction in Toxicity, Mobility, and Volume through Treatment - The primarily phase-transfertechnology employed in the alternative will result in no change in contaminant toxicity, orvolume. However, the extremely low rate of air emissions (8 gpm at <1.0 mg/L VOCs) willresult in a negligible health risk. Contaminant mobility will be increased through discharge to the


atmosphere. Those COCs subjected to natural attenuation will experience a reduction in toxicity,mobility and volume.

Short-Term Effectiveness - Protection will be achieved upon implementation of the 1C restrictinggroundwater use. The extremely low rate of air emissions associated with this alternative willresult in a negligible health risk.

Implementability - The technology and materials needed to implement the remedy are readilyavailable. However, it may not be possible to establish complete hydraulic capture of thecontaminant plume at the western Site boundary without adversely affecting the off-Site plumeinferred to exist north of the Site. A review of Figure 8-1 shows the estimated capture areaencompassing a large fraction of the on-Site contaminant plume, but not the entire plume. Theuse of multiple wells may improve the capture area. However, placing a pumping well farther tothe north than shown on Figure 8-1 increases the adverse effects on the inferred off-Site plume.Adverse effects include changing the direction of plume migration and size. The localmunicipality or other government agency would enforce the 1C.

Cost - The cost for this alternative is based on 15-years of remediation system operationfollowed by 5-years of additional groundwater monitoring. The duration of active remediation isbased on professional judgment. The 20-year present worth cost for implementing the alternative(based on a 7 percent discount rate) is $335,409. Detailed costing is presented in Appendix B.



8.3.6.2 Alternative 7b - Treatment via Ultraviolet Oxidation

This alternative involves treatment of extracted groundwater via UV/oxidation. Hydrogenperoxide is injected in the extracted groundwater prior to irradiation with UV light. Typically,easily oxidized organic compounds (such as PCE, TCE and VC) are rapidly destroyed inUV/oxidation processes. Treated groundwater would be discharged to surface water via stormsewer.

Alternative 7a consists of the following elements:


• Hydrogen peroxide storage/injection system.

• UV treatment system.

• Conveyance to storm sewer.




For costing purposes the remediation system is sized to achieve at least 99% removal of allCOCs.

Overall Protection of Human Health and Environment - This alternative would minimize orprevent off-Site migration of COCs until RAOs are achieved. The contaminant transport modelcalibrated during the RI (Hatchco, 2003) was used to estimate the time required to achieve RAOsin the off-Site area. Assuming complete hydraulic capture is established in 2003, the contaminanttransport modeling predicted that COC concentrations decline in off-Site areas to meet RAOs byyear 2017 (see Appendix D).

Remedial action objectives for vadose zone soil will be met through natural attenuation. Currentsoil conditions are protective of human health and the environment (direct ingestion and vaporinhalation exposure pathways) except as a potential source of groundwater contamination.Restrictions on groundwater use until RAOs are met will minimize the potential for humanhealth effects above a level of concern.

Compliance with ARARs - ARARs are discussed in Section 5.0. There are no location-specificARARs. The following summarizes the chemical- and action-specific ARARs for theAlternative.


• National Primary and Secondary Drinking Water Standards, Utah Primary DrinkingWater, Corrective Action Clean-up Standards, Alternate Corrective Action ConcentrationLimits and Groundwater Quality Standards - Contaminant fate and transport modelingpredicts ARARs will be met in off-Site groundwater under Alternative 7b in 2017.However, permanent reduction in COCs in off-Site areas may require continuedoperation of the remediation system beyond 2017 to prevent off-Site migration of COCsremaining on-Site above ARARs. For costing purposes, the total remedial duration isassumed to be 15 years.


• Clean Water Act Ambient Water Quality Criteria, National Pollutant DischargeElimination System (NPDES), and Utah Discharges to Surface Water (UPDES) -Discharge of treated groundwater to surface water would comply with the requirementsof a UPDES permit.


• National Guidelines establishing Test Procedures for the Analysis of Pollutants - Effluentquality under a UPDES permit would be established through analytical testingconforming to these guidelines.






Long-Term Effectiveness - This alternative would be effective in protecting human healththrough the use of ICs to minimize human exposure to Site contaminants until vadose zone soiland groundwater RAOs are met. Contaminant transport modeling predicts RAOs will be met inoff-Site areas by 2017 (see Appendix D).

This alternative offers a high degree of permanence through the removal of COCs fromgroundwater and the natural attenuation of the COCs beyond the hydraulic capture area createdby the pumping wells. The adequacy and reliability of an 1C is a function of the effectiveness ofthe enforcement agency. The local municipality would be the enforcement agency.

Reduction in Toxicity, Mobility, and Volume through Treatment - Contaminant toxicity, mobilityand volume will be reduced through the destruction of COCs by the UV/oxidation treatmentprocess. The portion of COC subjected to natural attenuation will experience a reduction intoxicity, mobility and volume.

Short-Term Effectiveness - No short-term risks to workers, the community or the environmentare posed under this alternative. Protection will be achieved upon implementation of the 1Crestricting groundwater use.

Implementability - The technology and materials needed to implement the remedy are readilyavailable. The local municipality or other government agency would enforce the 1C. Also, seediscussion in Section 8.3.6.2.

Cost - The cost for this alternative is based on 15 years of remediation system operation followedby 5 years of additional ground water monitoring. The duration of active remediation is based onprofessional judgment. The 20-year present worth cost for implementing the alternative (basedon a 7 percent discount rate) is $625,709. Detailed costing is presented in Appendix B.



8.3.6.3 Alternative 7c - Discharge to POTW

This alternative involves discharge of untreated groundwater to the South Davis Sewer DistrictFacility. Extracted groundwater would be conveyed via pipe to a point within the District'ssystem.

Alternative 7c consists of the following elements:


• Conveyance to sanitary sewer.




Overall Protection of Human Health and Environment - This alternative would minimize orprevent off-Site migration of COCs until RAOs are achieved. The contaminant transport modelcalibrated during the RI (Hatchco, 2003) was used to estimate the time required to achieve RAOsin the off-Site area. Assuming complete hydraulic capture is established in 2003, the contaminanttransport modeling predicted that COC concentrations decline in off-Site areas to meet RAOs by2017 (see Appendix D).

Remedial action objectives for vadose zone soil will be met through natural attenuation. Currentsoil conditions are protective of human health and the environment (direct ingestion and vaporinhalation exposure pathways) except as a potential source of groundwater contamination.Restrictions on groundwater use until RAOs are met will minimize the potential for humanhealth effects above a level of concern.-- . - - - - -

Compliance with ARARs - ARARs are discussed in Section 5.0. There are no location-specificARARs. The following summarizes the chemical- and action-specific ARARs for the alternative.


• National Primary and Secondary Drinking Water Standards, Utah Primary DrinkingWater, Corrective Action Clean-up Standards, Alternate Corrective Action ConcentrationLimits and Groundwater Quality Standards - Contaminant fate and transport modelingpredicts ARARs will be met in off-Site groundwater under Alternative 7c in 2017.However, permanent reduction in COCs in off-Site areas may require continuedoperation of this alternative beyond 2017 to prevent off-Site migration of COCsremaining on-Site above ARARs. For costing purposes, the total remedial duration isassumed to be 15 years.


• Clean Water Act Ambient Water Quality Criteria, National Pollutant DischargeElimination System (NPDES), and Utah Discharges to Surface Water (UPDES) - TheseARARs would be met by the District. The remedy would comply with and IndustrialWastewater Discharge Permit issued by the District.


• National Guidelines establishing Test Procedures for the Analysis of Pollutants - Effluentquality under a Industrial Wastewater Discharge Permit would be established throughanalytical testing conforming to District requirements.



W.S. Hatch Co. 8^21 HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004



Long-Term Effectiveness - This alternative would be effective in protecting human healththrough the use of an 1C to minimize human exposure to site contaminants until vadose zone soiland groundwater RAOs are met. Contaminant transport modeling predicts RAOs will be met inoff-Site areas by 2017 (see Appendix D).

This alternative offers a high degree of permanence through the removal of COCs fromgroundwater and the natural attenuation of the COCs beyond the hydraulic capture area createdby the pumping wells. The adequacy and reliability of an 1C is a function of the effectiveness ofthe enforcement agency. The local municipality would be the enforcement agency.

Reduction in Toxicity, Mobility, and Volume through Treatment - Contaminant toxicity, mobilityand volume will be reduced through treatment at the POTW. The portion of COCs subjected tonatural attenuation will experience a reduction in toxicity, mobility and volume.

Short-Term Effectiveness - Compliance with Industrial Wastewater Discharge Permit willpreclude sewer worker exposure above a level of concern. No other short-term risks to workers,the community or the environment are posed under this alternative. Protection will be achievedupon implementation of the 1C restricting groundwater use.

Implementability - The technology and materials needed to implement the remedy are readilyavailable. However, in a July 14, 2003 telephone conversation, Mr. Lyndon Tan with the Districtindicated they would be unwilling to accept untreated discharge. Treatment prior to dischargewould have to employ best available technology. Further, the permitee (Hatchco) would berequired to fund a study of impact to the District's facility should the discharge contain detectablelevels of chlorinated compounds. The local municipality or other government agency wouldenforce the 1C. Also, see discussion in Section 8.3.6.2

Cost - The cost for this alternative is based on 15 years of remediation system operation followedby 5-years of additional groundwater monitoring. The duration of active remediation is based onprofessional judgment. The 20-year present worth cost for implementing the alternative (basedon a 7 percent discount rate) is $206,566. Detailed costing is presented in Appendix B.




9.0 COMPARATIVE ANALYSIS

This section compares the retained alternatives to each other using the nine NCP criteria as ameasure. Table 9-1 presents the comparative analysis for the nine NCP criteria.

9.1 Overall Protection of Human Health and the Environment

The current extent of contamination both on- and off-Site is not known to pose a current risk tohuman health and environment above a level of concern. This conclusion is based on anassessment of risk posed by contaminated surface and subsurface soils and the lack of knowngroundwater use within the current inferred extent of contamination. In addition, surface andsubsurface soils do not pose a risk to hypothetical future on-Site occupants (non-residential)above a level of concern. However, the potential for future groundwater consumption results in ahypothetical future risk above a level of concern both on- and off-Site. In addition, current use ofcontaminated groundwater will not be known with certainty until EPA completes work onportions of the NPL Site surrounding the Hatchco Study Area.

All of the alternatives, with the exception of Alternative 1 (No-Action) include an 1C restrictinggroundwater use within the area inferred to be impacted by the groundwater contaminant plumeoriginating from the Site. Therefore, all of these alternatives (2-4, 6 and 7a-7c) offer an equallevel of protection. The primary difference between the alternatives is the time frame forachievement of RAOs and the associated date when the 1C can be discontinued.

Alternatives 2, 3 and 4 rely primarily on natural attenuation to achieve RAOs in groundwater.Alternative 4 may offer some incremental improvement over Alternatives 2 and 3 through theactive removal of contaminants from the vadose zone by phase transfer technology therebydiminishing the remaining source for groundwater contamination. Reduced infiltration andassociated leaching of COCs from vadose zone soils under Alternative 3 (capping) may delayachievement of soil RAOs when compared with other alternatives. Alternative 6 is expected toprovide additional improvement over Alternatives 1-4 by enhancing the natural attenuation ofCOCs in groundwater. However, Alternative 6 does not address contamination in the vadosezone. Alternatives 7a through 7c are expected to achieve groundwater RAOs in the shortest timeframe, however, operation of the remedies will need to be continued in order to maintaincompliance with RAOs. In addition, these alternatives do not address contamination in thevadose zone. Remedy operation will continue until the mass of COCs fixated to the aquifermatrix and vadose zone soils is depleted. This duration may exceed that required underAlternative 6.

9.2 Compliance with ARARs

All of the alternatives comply with chemical-specific ARARs. Natural attenuation of COCsdemonstrated at the Site will result in compliance with numerical clean-up goals for soil andgroundwater. Even under the No-Action Alternative, compliance with chemical-specific ARARsis expected to occur between 2022 and 2057. There are no location-specific ARARs for the Siteand compliance with action-specific ARARs will be achieved through compliance with UPDESpermits for water treatment plant effluent, requirements of an Industrial Wastewater Discharge


Permit for discharge to POTW, requirements for de-minimis emissions of VOCs, andrequirements for underground injection and fugitive dust control;

9.3 Short-Term Effectiveness

None of the alternatives involve significant disturbance of Site wastes. Therefore, few short-termimpacts are expected. Alternatives 4, 7a and 7c involve either discharge of COCs to theatmosphere or discharge of untreated groundwater to the sanitary sewer. Discharge to theatmosphere will not exceed the limits for a de-minimis discharge. Discharge to the sanitary sewerwill comply with the requirements for an Industrial Wastewater Discharge Permit for dischargeto POTW. Both of these restrictions imposed under action-specific ARARs will minimize short-term impacts. Under Alternative 1 protection is not achieved until groundwater quality meetsMCLs. However, under the remaining alternatives, protection is achieved once institutionalcontrols are implemented. Therefore, Alternatives 2, 3, 4, 6, and 7 offer similar degrees of short-term effectiveness with respect to the time required to achieve protection. Risks associated withvapor intrusion into future on-Site structures may be reduced in the short-term through theoperation of an SVE system.

9.4 Long-Term Effectiveness and Permanence

None of the alternatives require perpetual operation and all provide permanence once RAOs areachieved. Variation among the alternatives is limited to the time frame required to achievepermanence and the likelihood that an alternative would actually reduce the time required toachieve RAOs.

Alternatives 1 and 2 are expected to achieve RAOs in identical time frames. However,Alternative 2 offers more long-term effectiveness through the implementation of a groundwateruse restriction until RAOs are achieved. Alternatives 3 and 4 may achieve RAOs in a shortertime frame than under Alternatives 1 and 2. However, the ability of either alternative tosignificantly shorten the remediation time frame is uncertain. Alternatives 6 through 7c mayachieve RAOs in a shorter time frame than under Alternatives 3 and 4. The degree of certaintythat either alternative will significantly shorten the remediation time frame is higher than underAlternative 3 and 4 given these alternatives directly treat contaminated groundwater.

9.5 Reduction in Toxicity, Mobility or Volume through Treatment

All alternatives reduce contaminant toxicity, mobility and volume through natural attenuationprocesses including processes resulting in the destruction of COCs. Alternatives 1, 2 and 3 relysolely on natural attenuation to achieve reduction in contaminant toxicity, mobility and volume.Alternative 6 employs enhanced in-situ biological and chemical processes to achieve reduction incontaminant toxicity, mobility and volume. Although this alternative accelerates the destructionof COCs, the total mass of COCs destroyed is comparable to Alternatives 1 through 4.Alternative 4 and 7a transfers some of the COC mass from soils and groundwater to theatmosphere increasing contaminant mobility and reducing the volume of contaminants on-Site.The remaining mass of COCs experiences the same fate as under Alternative 1 through 3.Alternatives 7b and 7c reduce contaminant toxicity, mobility and volume through above-groundtreatment.


TABLE 9-1Comparative Analysis Using NCP Criteria


Controls


Alternative 4 - Soil Vapor Extractionw/Institutional Controls



Alternative 7a • Treatment via AirStripping w/Lnstitutional Controls

Alternative 7b -Treatment via

Ultraviolet Oxidationw/Institutional

Controls


w/InstitutionalControls

EffectivenessOverall Protection ofHuman Health andEnvironment

Improvements in groundwaier andvadose zone soil conditionsachieved through naturalattenuation. However, lack of 1Cmay result in health risk above alevel of concern. Permanent'compliance with MCLs in off-Siteareas is predicted to occur between off-Site2022 and 2057.

Achieves improvements ingroundwater and vadose zone soilconditions in the same time frame asAlternative 1. Implementation of 1Cwill minimize potential for humanhealth risk above a level of concern.Permanent compliance with MCLs in

areas is predicted to occurbetween 2022 and 2057.

Achieves improvements in groundwaterconditions more quickly than underAlternatives 1 and 2 by limiting migrationof COCs to groundwater. Vadose zonesoils will reach RAO's in similar or longertime frame man under Alternatives 1 and 2due to reduced infiltration and associatedleaching of contaminants. Implementationof 1C will minimize potential for humanhealth risk above a level of concern. Somereduction in the amount of time needed toachieve permanent compliance with MCLsas compared with Alternatives 1 and 2 inoff-Site areas may be achieved.

Achieves improvements in groundwaterand vadose zone soil conditions morequickly than under Alternatives 1-3 byremoving COCs from the inferredsource area. Implementation of 1C willminimize potential for human healthrisk above a level of concern. Somereduction in the amount of time neededto achieve permanent compliance withMCLs as compared with Alternatives 1and 2 in off-Site areas may be achieved.

Achieves improvements in groundwatermore quickly than under Alternatives 1-4 through enhanced in-situ destructionof COCs. Implementation of 1C willminimize potential for human health riskabove a level of concern. Somereduction in the amount of time neededto achieve permanent compliance withMCLs as compared with Alternatives 1and 2 in off-Site areas may be achieved.

Achieves improvements in off-Sitegroundwater more quickly than underAlternatives 1-4 (and possibly 6) throughextraction of contaminated groundwater.Improvements in vadose zone soils wouldoccur at the same rate as underAlternatives 1-3. Implementation of 1Cwill minimize potential for human healthrisk above a level of concern. Compliancewith MCLs in off-Site areas is predicted tooccur in 2017. However, permanentreduction in COCs in off-Site areasmay require continued operation ofthis alternative beyond 2017 tojrevent off-Site migration of COCsremaining on-Site above MCLs

ee Alternative 7a. iee Alternative 7a.

lompliance with Remedial Achieves RAO's and compliesAction Objectives andARARs

with chemical-specific ARARsthrough natural attenuation. Nolocation-specific ARARs.

Achieves RAO's in the same timeframe as Alternative 1. Complies withchemical- and action-specificARARs. No location-specificARARs.

Achieves RAO's in a shorter time framethan under Alternatives 1 and 2. Complieswith chemical- and action-specificARARs. No location-specific ARARs.

Achieves RAO's in a shorter time framethan under Alternatives 1-3. Complieswith chemical- and action-specificARARs. No location-specific ARARs.

Achieves RAO's in a shorter time framethan under Alternatives 1-4. Complieswith chemical- and action-specificARARs. No location-specific ARARs.

Achieves RAO's in a shorter time framethan under Alternatives 1-4. Complieswith chemical- and action-specificARARs. No location-specific ARARs


Long-Term Effectiveness Permanence is achieved throughnatural attenuation. Some risksassociated with groundwater usebefore RAO's are met.

Protection achieved at the time of 1Cimplementation. Reliability of 1Cdepends on effectiveness ofenforcement agency. Permanenceachieved through natural attenuation.

Protection achieved at the time of 1Cmplementation. Reliability of 1C depends

on effectiveness of enforcement agency.Permanence achieved through naturalattenuation. Degree of effectiveness inaccelerating achievement of groundwaterRAO's is unknown.

Protection achieved at the time of 1Cmplementation. Reliability of 1C

depends on effectiveness ofenforcement agency. Permanenceachieved through natural attenuation.Operation of remediation system will berequired for at least several years.Effectiveness (contaminant massrecovery) may be limited by Sitecharacteristics.

Protection achieved at the time of 1Cimplementation. Reliability of 1Cdepends on effectiveness of enforcementagency. Permanence achieved throughenhanced natural attenuation. Multipleapplication of chemical additive wouldbe required. Effectiveness (degree ofenhancement of COC biodegradation)may be limited by Site characteristics.

Protection achieved at the time of 1Cimplementation. Reliability of 1C dependson effectiveness of enforcement agency.Permanence achieved through extractionof contaminated groundwater and naturalattenuation of COCs in vadose zone soils.

See Alternative 7a. ee Alternative 7a.

Reduction of Toxicity,Mobility and Volume

Reduction in mobility, toxicity andvolume through naturalattenuation.

Reduction in mobility, toxicity andvolume is the same as for Alternative1.

Reduction in toxicity and volume is thesame as for Alternative 1. Contaminantmobility is lowered through reduction innfiltrating water.

Contaminant mobility increased throughhe discharge of extracted soil vapor.Potentially higher mobility than allother Alternatives. Reduction incontaminant toxicity and volumeroughly similar to alternatives 1-3.

Reduction in mobility, toxicity andvolume greater than under Alternatives1-4 through COC destruction.

Contaminant mobility increased throughair stripper discharge. Reduction incontaminant toxicity and volume roughlyimilar to alternatives 1-4.

Reduction in mobility,toxicity and volumepotentially greater thanunder Alternatives l-7athrough destruction ofCOCs by UV Oxidation

See Alternative 7b.

Short Term Effectiveness Involves no further remedialaction.

ô short-term risks as associated withthis alternative.

Short term risks are similar to those underAlternatives 1 and 2.

Short term risks are similar to thoseunder Alternatives 1 and 2. Risksassociated with vaport intrusion intofuture on-Site structures may bereducted through operation of a S VEsystem Risks associated with dischargeof soil vapor expected to be negligible.


Short term risks are similar to those underAlternatives \ and 2. Risks associated withdischarge of soil vapor expected to benegligible. '




TABLE 9-1Comparative Analysis Using NCP Criteria

; Evaluation Criteria. - ' " Alternative 1 - No ActionAlternative 2 - Monitored NaturalAttenuation (MNA) ^/Institutional

Controls'


Alternative 4 - Soil Vapor Extractionw/Institutional Controls

• - • • ' - " ' • "

Alternative 6 - Enhanced In-Situ : .;, •- .. - _ . , . -4."•^SE^jrr* «ss«^sr «*. w/Institubonal Controls •

Alternative 7b - :-Treatment via

Ultraviolet Oxidationw/Institutional

Controls

Alternative 7c-Discharge to POTW: w/Institutional

Controls

Implementability

Technical Feasibility

Administrative Feasibility

Availability of Servicesand Materials

Anticipated StateAcceptance

Anticipated CommunityAcceptance

No Action Required.

/

No Action Required.

No Action Required.



No technical issues are associated withthis alternative.

The willingness of the municipality toadminister the 1C ha£ not beenevaluated. An agreement would haveto be reached with the City of WoodsCross to enforce a groundwater userestrictions.

Services and materials are readilyavailable.




See Alternative 2.

See Alternative 2.




See Alternative 2.

See Alternative 2.




See Alternative 2.

See Alternative 2.



Groundwater modeling indicates it may notbe possible to establish hydraulic capture ofentire plume along western Site boundaryw/out adversely affecting overlappingpetroleum plume to the north.

See Alternative 2.

See Alternative 2.



See Alternative 7a.

See Alternative 2.

See Alternative 2.



See Alternative 7a.

The POTW will notaccept untreateddischarge. Notimplementable.

See Alternative 2.



Cost

Capita] Costs

Present Value O&M Costs

Periodic Costs

Present Value

$0

$0

$0

$9,531

$58,167

$0

$67,698

$89,040

$58,167

$0

$147,207

$53,945

$92,942

$11,435

$158,322

$149,848

$42,694

$136,258

$328,800

$70,687

$260,261

$4,461

$335,409

$224,197

$397,052

$4,460

$625,709

$49,109

$152,986

$4,461

$206,556



9.6 Implementability

All of the alternatives except Alternative 7c are technically and administratively implementable.Alternative 7c is not administratively implementable.

9.7 Cost

Alternative 1 has no costs associated with it. Alternative 2 through 7b are ordered in increasingcost. Alternative 7c is less costly than Alternative 6 and more costly than Alternative 4.

9.8 State Acceptance

To be determined during the FFS comment period and proposed plan.

9.9 Community Acceptance

To be determined during the FFS comment period and proposed plan. .


10.0 REFERENCES

American Public Health Association (APHA), American Water Works Association, and WaterEnvironment Federation, 1995, Standard Methods for the Examination of Water andWastewater. (19th ed.). Washington, DC: American Public Health Association.

ASTM, 1995, Standard guide for risk-based corrective action applied at petroleum release sites.American Society for Testing and Materials. ASTM Designation: E 1739-95. November.

Clark, David W., Cynthia L. Appel, Patrick M. Lambert, and Robert L. Puryear, 1990,Groundwater Resources and Simulated Effects of Withdrawals in the East Shore Area ofthe Great Salt Lake, Utah; Technical Publication No. 93; State of Utah Department ofNatural Resources.

Fetter, C.W:, 1999, Contaminant Hydrogeology (2nd ed.). Upper Saddle River, NJ: Prentice-Hall,p. 347.

Gibbons, R.D., 1994, Statistical methods for groundwater monitoring. John Wiley & Sons, NewYork. 286 pp.

HDR , 2003, Final Remedial Investigation Report, Former W.S. Hatch Co. Facility, WoodsCross, UT, December 2003.

HDR, 2002, Remedial investigation/feasibility study, final sampling and analysis plan. Preparedfor W.S. Hatch Co., Woods Cross, Utah. HDR Engineering, Inc., Denver, CO. January.

Howard, P.H. 1990, Handbook of Environmental Fate and Exposure Data for OrganicChemicals. Lewis Publishers, Chelsea, Michigan.

Lockheed Martin. 2000, Data Validation Report, Woods Cross 800 W. Plume, Audit Number 08-46-00, prepared for ESAT Region 8.

Personal Communications, Russ Leclerc. March 8, 2002, Conference call between USEPA,USEPA's oversight contractor, UDEQ, and HDR Engineering.

Personal Communication, Russ Leclerc, March 27,2002, Conference call between USEPA,USEPA's oversight contractor, UDEQ, and HDR Engineering.

PSI. 1998, Subsurface Environmental Investigation for the Former Jack Kelley Trucking Site,500 West 800 West, Woods Cross, Utah. May 5.

ROCS, 1998, Subsurface Investigation Report - Former Hatchco Trucking, 500 South 800 West,Woods Cross, Utah. November 11.

Splus, (2000), Professional release 1. MathSoft Inc. Copyright 1988-1999.


Thomas, H.E., and W.B. Nelson, 1948, Ground Water in the East Shore Area, Utah, Part 1,Bountiful District, Davis County, Utah; State Engineer 26th Biennial Report, pp. 53-206.

United States Environmental Protection Agency, 1988, Superfund Exposure Assessment Manual.EPA/540/1-88/001. Office of Emergency and Remedial Response, Washington, DC.

United States Environmental Protection Agency, 1989, Risk assessment guidance for Superfund.Volume I: Human health evaluation manual (Part A, Baseline risk assessment). U.S.Environmental Protection Agency, Office of Emergency and Remedial Response,Washington, DC. EPA-540/1-89/002. December.

United States Environmental Protection Agency, 1990a, Guidance for data usability in riskassessment: Interim final. U.S. Environmental Protection Agency. EPA/540G90008.October.

United States Environmental Protection Agency, 1990b, Subsurface Contamination ReferenceGuide. EPA/540/2-90/011. Office of Emergency and Remedial Response, Washington,DC.

United States Environmental Protection Agency, 199la, Risk assessment guidance forSuperfund. Volume I: Human health evaluation manual (Part B, Development of risk-based preliminary remediation goals). U.S. Environmental Protection Agency, Office ofEmergency and Remedial Response, Washington, DC. PB 9285.7-01B. December.

United States Environmental Protection Agency, 1991b, Risk assessment guidance forSuperfund. Volume I: Human health evaluation manual supplemental guidance. Standarddefault exposure factors. Interim Final. OSWER Directive 9285.6-03. U.S.Environmental Protection Agency, Office of Emergency and Remedial Response,Washington, DC.

United States Environmental Protection Agency, 1992, Guidance on risk characterization for riskmanagers and risk assessors. F.H. Habicht n, Memorandum. U.S. EnvironmentalProtection Agency. February.

United States Environmental Protection Agency, 1994, Evaluating and identifying contaminantsof concern for human health. Region 8 Superfund Technical Guidance. No. RA-03:Contaminants of Concern. U.S. Environmental Protection Agency, Denver, Colorado.September.

United States Environmental Protection Agency, 1996a, Soil Screening Guidance: TechnicalBackground Document. EPA/540/R95/128. Office of Solid Waste and EmergencyResponse. Washington, D.C: PB96-963502.

United States Environmental Protection Agency 1996b, Soil Screening Guidance: User's Guide.EPA/540/R96/018. Office of Solid Waste and Emergency Response. Washington, DC.PB96-963505.


United States Environmental Protection Agency 1996c, Superfund Chemical Data Matrix.EPA/540/R-96/028. Office of Solid Waste and Emergency Response, Washington, DC.PB94-963506.

United States Environmental Protection Agency 1997, Exposure factors handbook. Volumes Ithrough HI. EPA/600/P-95/002F. U.S. Environmental Protection Agency, Office ofResearch and Development, Washington, DC.

United States Environmental Protection Agency, 1998, Technical Protocol for EvaluatingNatural Attenuation of Chlorinated Solvents in Ground Water. EPA/600/R-98/128.Office of Research and Development. Washington, DC: Government Printing Office.

United States Environmental Protection Agency, 1999, Office of Solid Waste and Emergencyresponse Directive 9200.4-171.

United States Environmental Protection Agency, 2000, A Guide to Developing andDocumenting Costs During the Feasibility Study, EPA 540-ROO-002, July 20000.

United States Environmental Protection Agency, 200la, Supplemental guidance for developingsoil screening levels for Superfund sites. Peer Review Draft. U.S. EnvironmentalProtection Agency. Solid Waste and Emergency Response. OSWER 9355.4-24. March.

United States Environmental Protection Agency, 2001b, Risk assessment guidance forSuperfund. Volume I: Human health evaluation manual. (Part E, Supplemental guidancefor dermal risk assessment). Interim review draft for public comment. U.S.Environmental Protection Agency, Office of Emergency and Remedial Response,Washington, DC. OSWER 9285.7-02EP. EPA/540/R/99/005. September.

United States Environmental Protection Agency, 2002, Integrated Risk Information System(IRIS). On-line database. U.S. Environmental Protection Agency, Office of Research andDevelopment, Cincinnati, OH. http://www.epa.gov/iriswebp/iris/index.html

United States Environmental Protection Agency, 2003, Region 3 Risk-Based Concentration(RBC) table. On-line database. U.S. Environmental Protection Agency, Philadelphia, PA.http://www.epa.gov/reg3hwmd/risk/index.htm. Accessed in March 2003.

USD A, 1968, Soil Survey - Davis-Weber Area, Utah. United States Department of Agriculture,Soil Conservation Service, July


.---" x - ,'

&• LAIr ^-i

i ..a Tnpo USA 2.O Copyri^K © 1999 DeLorme Yarmouth, ME O4O96 Scale: 1 : 137,500 Detail: 1O-S


Site Location Map

HATCHCO Focused Feasibility StudyW.S. Hatch Co.Woods Cross, Utah

Data

March 2004

Figure

1-1

500 SOUTH STREET

N

LEGENDHATCHCO PROPERTY BOUNDARY


Site Plan

,Feasib(HATCHCO)^Woods

lity StudyHatch Co.

Cross, Utah

SCALE: 1"=200

Date

MARCH 2004

Figure

1-2

en

•

Ien

i/i

8g-m O

SCALE: 1"=150500 SOUTH STREET

PHILLIPS 66 BULKLOADING FAOLJTY

FRONTAGE PARCELS

POWERSUBSTATION

RBMOVEDFRENCHDRAM

FUELJNGSTATION

\ REMOVED\JpJJWATER'SEPERATOR

kETHANEFUEL

STATION KALAHARI PROPERTY

PUMP BOLER

HOUSE ROOM

TANGLEWOOD ACRES SUBDIVISION

LIGHTINDUSTRIAL

AREA

LEGENDU HATCHCO PROPERTY BOUNDARY

APPROXIMATE LOCATION OF FORMER BUILDING AND STRUCTURES

o ~

CL OHDR Engineering, Inc.

Historic Site iFeatures Location Plan Date

MARCH 2004]

ÛHTnuniTN Focused Feasibility StudyHATCHCOjw S Hatch Co.

Woods Cross, Utah

Figure

1-3

o —


MONITORING WELL

GEOLOGIC CROSS-SECTION TRAVERSE

U)

500 SOUTH STREET


Geologic Cros

Woods

N

SCALE: 1"=200'

s—Section Traverse

d Feasibility StudyCo.

Data

MARCH 2004

:ross. Utah

Figure

2-1

MW-14S MW-12S

A4310

550'

MW-10S MW-3S MW-1D

440' 310'

4310

4300

4290

4300

4290

4280

4270

4260-

coO

4250LJ

4240

4230-

4220-

4210

-800-

UPRRWEST

STREET

950WEST

STREET

rr^<"^<>^^>>^^>/->^Xx^<\3<g")^'iR'' l-lTTT.j_'_|TT7ljJrrT- TTi 7~

FINES: ' ,^^,^ •

SAND

3ai£^^

SAND'

^fey^*fei^Mi^^^SAND

SAND/FINE SANDJ-V

lil

_ r. r- -^ — AND/FINE SAND ••"•',':.•".£•_'•^J1' • •';: '• • --•"'

Sttei nbdierfeE

-SAN6-

=fTS~=TEnl='UiLJiLJ

4280

4270

4260

co

-t—'

D

4250 o>

4240

4230

4220

4210

4200- 4200

LEGEND NOTES

SILTY SAND/FINE SAND

GRAVEL W/ FINES

SILT

INFERRED BOUNDARY

MONITORING WELL

STATIC WATER LEVEL

SCREENED INTERVAL

1. SEE FIGURE 2-1 FORLOCATION OF GEOLOGICCROSS-SECTION.

2. STATIC WATER LEVELSCOLLECTED OCT. 25,2002.


Geologic Cros

Woods

SCALE: HORIZONTAL: 1"=150'VERTICAL: 1"=15'

— Section A—A

Feasibility StudyCo.

ross, Utah

Date

MARCH 2004

Figure

2-2

o —

^

V O <fA • A •

(QN <b.Xnr n.3 T v > v

ll/Jt£V/

£v

560 sduTH TREET

nXJtyl'

/ 500 SOUTH STREET


MW®3S MONITORING WELL

INFERRED WATER TABLECONTOUR

DATA GAP


Water Table(October 25,

CHATCHCO)W°SUS

Woods

Contour Map2002)d Feasibility Study

Hatch Co.;ross, Utah

N

10

SCALE: 1"=200'

Date

MARCH 2004

Figure

2-3

LLJUJDC

CO

^w

UJ

og

ALL ND ALL ND

SS - 005Tetrachloroethene 0.004Trichloroethene 0.001

©ALL ND

49

ALL ND©

ALL ND

10®

ALL Ml)

119

ALL ND

~lN

ALL NDSS - 006BenzeneToluene

0.0010.012

SS - 009cis-1, ;Trichloro

|I

'JALL ND

139

ALL ND

-Dichloroethene 0.011ethene 0.002

SCALE: 1"=50

700 SOUTH ST

NOTES

1. ALL RESULTS ARE IN mg/kg. 39

ND


Surface Soil

/uiiTnunnA Focust d Feasibility Study( HATCH CO) ws H>tcn Co.

Woods press, Utah

LEGEND•HATCHCO PROPERTY BOUNDARY

SURFACE SOIL SAMPLE LOCATION

NON-DETECT

Sampling ResultsDate

MARCH 2004!

Figure

2-4

LULUCC\-co

COLU

aaCO

33)

ND

132©ND

ND

94©ND

ND

56

ND

19©ND

134©ND

ND

93©ND

58©ND

55©ND

20

ND

163ND

160

ND

135©ND

130©ND

97©ND

92©ND

59©ND

ND

21©ND

17©ND

164ND

SCALE: 1"= APPROX. 35'

I ©ND ©ND ©ND 93 ND W NU <±>INL> O^L- a?'"" ^"" __ _ _ _

89

NDI --- j1 --- '


SOIL GAS SAMPLE LOCATION

SOIL GAS CONCENTRATIONNON-DETECTAPPROXIMATE LOCATION OFFORMER BUILDING OR STRUCTURE

700 SOUTH STREETNOTES1. ALL CONCENTRATIONS ARE IN ug PER

LITER OF SOIL GAS.

2. RESULTS ARE FOR CHLORINATED VOC'sAND BTEX ONLY. HDR Engineering, Inc. (HATCHCO)5,TS

Soil Gas Sampling Results (5' Depth)

id Feasibility Studyhatch Co.

Woods Cross, Utah

Date

MARCH 2004

Figure

2-5

IllLUDC

CO

coLU

ao00

$162 163

133 134

95 96

94

58

19 2_0

18

160

97

93 92

59

55 54

21

17

91

53

22

16

—fc~164

—®~165 166 167 168 169

159 158 157 156 155 154

135 136 137

132 131 130 129 128

98 9_9

138

127

100

90 89

60 6J

52

62

51

HOUSE

23 24e ®

~ 1?~, ® e g JB e JB_ e _®_ ® _®_ ® ^_ * £_ *

170 N

153 152

149

116

111

78

73

40

35

150 151

1159

ND@20>--

114

SCALE: 1"= APROX. 35'

203

112 113

77 76

74 75

I39 38

36 37

SHOP

3 2 1

o ,-

89e

ND

ci:

LEGEND-HATCHCO PROPERTY BOUNDARY


SOIL GAS CONCENTRATIONNON-DETECTAPPROXIMATE LOCATION OFFORMER BUILDING OR STRUCTURE

NOTES700 SOUTH STREET

1. ALL CONCENTRATIONS ARE IN ug PERLITER OF SOIL GAS.

2. RESULTS ARE FOR CHLORINATED VOC'sAND BTEX ONLY. HDR Engineering, Inc.

Soil Gas Sarrjpling Results (15' Depth)

Feasibility StudyCo.

Woods ross, Utah

Date

MARCH 2004|

Figure

2-6

LULJJDCh-co

COLU

OO00

/

/161

,132 131

94 93

19

58

55

18

62 163

160

130e

17

95 96 97 98

91

59 60

54 53

22

16

164 165 166 167 168 169

159 158 157 156 155 154

133 134 135 136 137144 1!45 146 147 148

129 128

WELDING SHOP

119 118 117

ITT"

~1

m170 N

153 152

149 150 151

116 115

111 112

114

2033®11


!78

73

77

74 75

[

40

35

39

36 37

I ® © © ® W W TO TO ^ ~ - _

SHOP

LEGEND- — — HATCHCO PROPERTY BOUNDARY

© SOIL GAS SAMPLE LOCATION

ED SOIL GAS CONCENTRATION

ND NON-DETECTI 1 APPROXIMATE LOCATION OF1 i FORMER BUILDING OR STRUCTURE

700 SOUTH STREETNOTES1. ALL CONCENTRATIONS ARE IN ug PER

LITER OF SOIL GAS.

2. RESULTS ARE FOR CHLORINATED VOC'sAND BTEX ONLY. HDR Engineering, Inc.

Soil Gas Sampling Results (25' Depth)Date

MARCH 2004

>Focused Feasibility Study/W.S. Hatch Co.Woods Cross, Utah

Figure

2-7

220

219

218

217

216 LUUr

co

COHI

oo00

SCALE: 1"=50'

700 SOUTH STREET

NOTES

1. ALL CONCENTRATIONS ARE IN ug PERLITER OF SOIL GAS.

2. ONLY REPORTABLE DETECTIONS AREPRESENTED.

3. RESULTS ARE FOR CHLORINATED VOC'sAND BTEX ONLY.

89©

"737"

LEGEND•HATCHCO PROPERTY BOUNDARY


SOIL GAS CONCENTRATION


Off - Site Soil Gas (Sampling Resu'lts (5' Depth)ûHTnunf^ Focused Feasibility Study(HATCH CD JWS Hatch Co.

Woods Cross, Utah

Date

MARCH 2004

Figure

2-8

Dl

T

IDw3D>

10

O »-

Sri.o. o ?

i 80

0 W

ES

T

ST

RE

ET

2 i «i|/ /

'

i

/ DPS- 140-020/ All ND

DPS- 140-030All ND

140

DPS-104-0161,2,4- TrimethylbEthylbenzeneNaphthalenen-Propylbenzene

DPS- 104-026

DPS-064-020 \1,3,5- Trimethylbenzene 74.713 \4-lsopropyltoluene 39.014 \Ethylbenzene 30.574 \Isopropylbenzene 89.833 ^^m-Xylene and p-Xylene 35.808 \^n-Propylbenzene 67.768 \sec-Butylbeniene 161.632 \tert-Butylbenzene 13.017 \Toluene 1.890 \Trichloroethene 2.834 \

DPS-064-025 \All ND \

DPS-064-035 \cis-1.2-Dichloroethene 0.033 V^Trichloroethene 0.021 ^ TjVinyl Chloride 0.003 ______ ' £4

1 &~—^ A" ND

LEGEND NOTES- HATCHCO PROPERTY BOUNDARY , ALL CONCENTRAT|Q

SUBSURFACE SOIL SAMPLING LOCATION

NON-DETECT 2. ONLY ANALYTICAL020 SAMPLE ID (LAST 3 DIGITS LIMITS ARE PRESEr

DENOTE SAMPLE DEPTH)

, / DPS-082-016snzene 0.054 \ / Ethylbenzene 0.563

0.051 \ / Isopropylbenzene 2.3050.365 \ / Naphtha ene 8.2590.530 \ / n-Propylbenzene 17.965

\ / sec-Butylbenzene 11.471

\ /^s^\ / 1.2.4- Trimethylbenzene 0.583

104 / Naphthalene 4.639/ Tetrachloroethene 0.930

/ Trichloroethene 90.956

82

207

DPS-207-009 jjj1,2,4- Trimethylbenzene 33.602 *^v1,3,5- Trimethylbenzene 15.343 \\

cis- 1.2- Dichloroethene 9.236 \ pPS-0'Ethylbenzene 9.773 \ All NDIsopropylbenzene 4.219 .\m-Xylene and p-Xylene 32.450 \ DPS-OîNaphthalene 53.364 \ cis- 1.2o-Xylene 16.877 ^ Trichlor

Toluene 4.326Trichloroethene 22.292

DPS-207-020Napthta ene 0.567

700 SOUTH STREET

NS ARE IN mg/kg. T V "V > Subsurface S

RFSUITS FXCFFDING DETECTION JL M^JL V

^TED- HDR Engineerina .nc. (HATCHCD)!Woods

_^ MDPS-171-007 ^\7Y

All NO I/ "^fck^

i l i


1-007

1-013-Oichloroelhene .004jethene .002

1

Date

Dil Sampling Results MARCH 2004

Figure

d Feasibility Studyitch Co. - 29>oss, Utah

! i

800

W

ES

T

STR

EE

Ten

.

T «i

|

/

( /

1DPG-I1U.-035

1.1— Dichloroethone1.2.4- TrimethylDenzeneBenzeneChloroethanecis- 1,2- DichloroetheneEthylbenzeneNaphthaleneTetrachloroetheneToluenetrans- 1.2- DiehloroetheneTrichloroetheneVinyl Chloride

DPG-061-031 . |

1.1.1- Trichloroethane 1.89 /1.1- Dichloroethone 38.9 /1.1- Dichloroethene 1.52 /Benzene 3.13 /Chloroethane 3.65 /Chloromethane 0.73 /cis- 1.2- Dichloroehtene 2739 /Ethylbenzene 0.23 /Naphthalene 7.14 /n-Propylbenzene 0.34 /Tetrochloroethene 5.36 /Toluene 0.42 /trans- 1.2- Dichloroethene 34.3 /Trichloroethene 1054 /Vinyl Chloride 467 /

/ DpG-ltO-032/ l.i — Dichloroethone 0.4

/ 1,2.4- Trimethylbeniene 4.5/ Benzene 0.41

/ Chloromethane 0.59/ cis- 1.2- Dichlorodhene 13.7/ Ethylbenzene 0.44

/ Isopropylbenzene 0.21/ m— Xylene and p— Xylene 1.32

/ Naphthalene 13.1/ n-Propylbenzene 0.56

/ o-Xylene 0.87/ Tetrochloroethene 0.9

/ Toluene 0.49/ Trichloroethene 39.4

/ Vinyl Chloride 1.36

^—40

^

^

4

i82

954 207

OPG-207-036

1.1,1- Trichloroethane 5.121,1- Dichloroethane 16.21,1- Dichloroethene 0.751.2,4- Trimethylbenzene 1.05Benzene - O.BChloroethane 2.25Chloromethane 0.65cis-1,2- Dichloroethene 481Ethylbenzene 0.4m— Xylene and p-Xylene 0.63Naphthalene 8.08o-Xylene 0.47Tetrachloroethene 1 3.9Toluene 0.78trans- 1.2- Dichloroethene 5.74Trichloroethene 1 346Vinyl Chloride 92.3

700 SOUTH SIR

LEGEND NOTES-HATCHCO PROPERTY BOUNDARY ^ ALL CONCENTRAT|QNS ARE |N /L T

DIRECT-PUSH GROUNDWATER SAMPLING LOCATION f331 SAMPLE ID (LAST 3 DIGITS 2. ONLY ANALYTICAL RESULTS EXCEEDING

DENOTE SAMPLE DEPTH) DETECTION LIMITS ARE SHOWN. HDR

/ OPG-OB2-OU./ 1,1.1- Trichloroethone 0.25/ 1.1- Dichloroethane 0.9

/ 1.1- Dichloroethene 0.27/ 4-lsopropyltoluene 0.21

/ Benzene 0.21/ cis- 1.2- Dichloroethene 289

/ Ethylbenzene 0.64/ Isopropylbenzene 0.21

/ m-Xylene and p— Xylene 0.93/ Naphthalene 5.44

/ .n-Butylbenzene 0.35/ n-Propylbenzene 0.44

' Tetrochloroethene 2.36Toluene 0.69trans- 1.2- Dichloroethene 2.25

^ Trichloroethene 151^-^^ Vinyl Chloride 7.62

41

V

1 î

\ DPG-Otl-03t\ 1.1.1- Trichlo\ 1.1- Dichlorw\ Cnloromethan\ cis- 1.2- Dit\ Naphthalene\ Tetrachlorooth\ Toluene\ Trichloroetheru\ Vinyl Chloride

EET

^ Direct— Push G-. j ^ Sampling RestM ^. ^

i UHTf*UOn^ f"00"861

Engineering, Inc. ^HillWIuUJw.S. HaWc»dsC

rcjitIFtchrosi

1 ™


oethone 1 .09thene 0.9

0.81hloroethene 1 .38

0.52me 5.43

0.310.951.23

J

>undwateri vlARCH 2004S

Figureeasibility StudyCo. o in, Utah

N

SCALE: 1"=200'

w

Cn

T3

o>I18

o ,~

\a o

OUTH STREET

500 SOUTH STREET1.1- Dichloroethone1,1— DichloroetheneBenzenecis- 1.2- DichloroetheneTetrochloroethenetcons-1,2- DichloroetheneTrichloroetheneVinyl Chloride 1,1- Dichtoroethone 1.32

Benzene 1.97cis- 1.2- Oichloroethene 87.4Methyl-tertbutyl-ether 407trans-1.2- Dichloroethene 7.22Trichloroethene 17Vinyl Chloride 61.1

Benzene 0.71Chloromethane 1.22cis-1.2-Dichloroethene 9.48Methyl-tertbutyl-ether 4.18Trichloroethene 8.4BVinyf Chloride 2.31

1,1- Dichtoroelhonecis— 1,2— DichloroetheneTetrochloroethenetrans-1,2- DichloroethenoTrichloroetheneVinyl Chloride

1.1 —Dichloroethone1,1-DichloroetheneBenzenecis-1,2-DichtoroetheneTetrochloroethenetrans-1,2-DichloroetheneTrichloroetheneVinyl Chloride

1,1,1 — Trichloroethone1,1 -Dichloroethone1.1- DichloroetheneBenzenecis-T.2-DichloroetheneTetrachloroethenetrans-1.2-DichloroetheneTrichloroetheneVinyl Chloride

XMW-IOS MW-3DMW-3S

1,1 -Dichloroethonecis-1.2-DichloroetheneTetrachloroetheneTrichloroethene

1.1 -Dichloroethone1.1 -DichloroelheneBenzenecis-1.2-DichloroetheneIsopropylbenzeneTetrachloroetheneToluenetrans-1,2-DichloroelheneTrichloroetheneVinyl Chloride

MonitoringSampling Results(October 2002)

.S. Hatch Co.HDR Engineering, Inc.

LEGEND

HATCHCO PROPERTY BOUNDARY

MW^3S MONITORING WELL

1. ALL RESULTS ARE IN ug/L.

2. ONLY ANALYTICAL RESULTS EXCEEDINGDETECTION LIMITS ARE SHOWN.

Date

MARCH 2004]

2-11

500 SOUTH STREET



©64 DIRECT-PUSH GROUNDWATERSAMPLING LOCATION

1.

NOTES:ISOCONCENTRATION CONTOURS ARE PRESENTEDIN mg/L. CONTOURS ARE DASHED WHERE INFERRED.

2. CONTOURS REPRESENT A SUM TOTAL OF ALLCHLORINATED ETHANE AND ETHENE COCENTRATIONS.


Isoconcentratiorji Contour Map ofChlorinated Hydrocarbons in ShallowGroundwater (Cctober 2002)

ÛMTnunn^Focused Feasibility Study(JIATCHCOJW.S. Hatch Co.

Woods Cross, Utah

Djrts

MARCH 2004

Figure

2-12

EPA (2001)2DPCE-8TCE-280C12DCE-200VC-2

EPA (2002)WPH01TCE-13C12DCE-28VC-5

EPA (2001)2SPCE-0.7TCE-58C12DCE-270VC-50

[PA (2002)WPH 10TCE-58C12DCE-538VC-215MTBE is PRESENT!

HATCHCO (2002)MW-14S

PCE-0.5TCE-507C12DCE-662T12DCE-28VC-98


TCE-95C12DCE-283VC-60

HATCHCO (2002)MW-4S

TCE-8C12DCE-9VC-2MTBE-4

N

SCALE: 1"=500'

— EPA (1997)BGW32


_L

EPA (2000)GW19


EPA (1997)BGW20

TCE-18C12DCE-72

EPA (2000)GW20

ND

Z


TCE-17C12DCE-87VC-61MTBE-407

HATCHCO (2002)MW-3D

PCE-14TCE-4C12DCE-3

500

HATCHCO (2002)GEOPROBE 140

PCE-1TCE-39C12DCE-1'VC-1

z7

HATCHCOMW-13S

PCE-2TCE-50C12DCE-T12DCE-VC-22

(2002) HATCHCO (2002)MW-12S

PCE-2TCE-44C12DCE-113T12DCE-2VC-31

\

HATCHCO (2002)MW-9S

PCE-1TCE-2C12DCE-1

CO


TCE-11C12DCE-23VC-5

!FSI (1998)MW-7

PCE-NDTCE-ND

7-


PCE-5TCE-1054C12DCE-2739VC-467

/ \

oo

PSI (1998)MW-5

PCE-NDTCE-ND

7

HATCHCO (2002)MW-8S

ND

HATCHCO (2002)MW-3S



• GROUNDWATER SAMPLING LOCATION

— DATE OF EPA SAMPLING EVENT— EPA SAMPLE LOCATION I.D.

— DATE OF HATCHCO SAMPLING EVENT— HATCHCO SAMPLE LOCATION I.D.

— DATE OF SAMPLING BY CONSULTANT TOKALAHARI PROPERTIES

— PSI SAMPLING LOCATION I.D.

NOTES:1. ALL CONCENTRATIONS SHOWN IN ug/L.

2. ONLY CHLORINATED ETHENES AND MTBERESULTS ARE PRESENTED.

3. PCE= TetrachloroetheneTCE= TrichloroetheneC12DCE= cis-1,2- DichloroetheneT12DCE= Trans-1,2- DichloroetheneVC= Vinyl ChlorideMTBE= Methyl Tertbutyl EtherND=NON-DETECT

\£

HATCHCO (2002)MW-2S


HATCHCO (2002)MW-1D

PCE-11TCE-2



HATCHCO (2002)MW-1S

PCE-46TCE-1



N EPA (2000)-GW-08'CE-13'CE-1




CompilationGroundwater

AiHTnunnA Focused Feasibility Study(HATCHUUjw.S Match Co.

f AvailableChemistry

DataDate

MARCH 2004

Woods Cross, Utah

Figure

2-13

Figure 2-14MW-2S Concentration vs. Time Plot

1000

Q>Ocoo

—»-TCE

-•-PCE

-*-cis-1.2-DCE

-H-VC-*-cis-1,2-DCE/TCE

-•-VC/TCE

0.1

Sep-02 Oct-02 Dec-02 Jan-03 Mar-03 May-03 Jun-03 Aug-03

W.S. Hatch Co. 'Focused Feasibility Study HDR Engineering, Inc.


1000

100

I*o1 10+J

IoO

0.1

Sep-02

-•-TCE-•-PCE

-*-cis-1,2-DCE

-*-VC-*-cis-1,2-DCE/TCE

-•-VC/TCE

Oct-02 Dec-02 Jan-03 Mar-03 May-03 Jun-03 Aug-03



1000

100

o>

co

10

ooo

0.1Sep-02

-•-TCE-•-PCE-A-cis-1,2-DCE-H-VC-*-cis-1,2-DCE/TCE-•-VC/TCE




1000

100

o>3

oocoo

-•-TCE-m-PCE—At- cis-1,2-DCE

-*-VC-*-cis-1,2-DCE/TCE-•-VC/TCE

Sep-02 Oct-02 Dec-02 Jan-03 Mar-03 May-03 Jun-03 Aug-03



1000

100

o>

co'•§ 10*J

0)ooo

0.1

Sep-02

-TCE

-PCE

-cis-1,2-DCE-VC

-cis-1,2-DCE/TCE-VC/TCE




10000

1000

o>

otc

I0)ooo

100

10

0.1

Sep-02

-TCE-PCE

-cis-1,2-DCE-VC

-cis-1,2-DCE/TCE



OUTH STREET

— — 5QO SOUTH STREET

+ + +

+ + +1Q4+

+ + + 207+ +

+ + + + + ±



©64 DIRECT-PUSH GROUNDWATERSAMPLING LOCATION

HATCHCO PLUME

CHLORINATED SOLVENT PLUME (THIRD-PARTY)

FUEL HYDROCARBON PLUME (THIRD-PARTY)

NOTES1. PLUME BOUNDARIES ARE DRAWN APPROXIMATE.


GrpundwaterThird —Party

N

SCALE: 1"=200'

Map Showing Inferred:ontaminant Plumes

Date

MARCH 2004I

/unTnunn^ Focused Feasibility StudyHAIUHUUJWS Hatch Co.

Woods ^ross, Utah

Figure

2-20

CMOOCM

OCM

LOCMOCM

PCE (MCL = 5 ug/L) TCE (MCL = 5 ug/L) DCE (MCL = 70 ug/L) VC (MCL = 2 ug/L)

U/l

PCE = PERCHLOROETHENETCE = TRICHLOROETHENEDCE = DICHLOROETHENEVC = VINYL CHLORIDEMCL = MAXIMUM CONTAMINANT LEVEL*-^ OBSERVED GROUNDWATER FLOW DIRECTION

SCENARIO 2: LINEAR DECAY OF CURRENT ASSUMEDSOURCE CONDITION TO 2020.


ModeledAttenuation inUnder ScenaricHATCHCO

GrouHdwater Contaminant Plume/ear 2002, 2010, and 20252

d Feasibility StudyHatch Co.

Woods Cross, Utah

Date

MARCH 2004Figure

2-21

N/ 1

\500 SOUTH STREET SCALE: 1"=200'

500 SOUTH STREET



O64 DIRECT-PUSH GROUNDWATER SAMPLING LOCATION

MW_5 PRE-RI SAMPLING STATIONS• (SEE FIGURE 6-13 FOR

CONCENTRATION DATA)•—PCE TETRACHLOROETHENE MCL (5 ug/L)— TCE TRICHLOROETHENE MCL (5 ug/L)--cDCE cis_ 1,2- DICHLOROETHENE MCL (70 ug/L)

vc VINYL CHLORIDE MCL (2 ug/L)

NOTES1. ONLY DETECTED CONTAMINANTS ABOVE

ESTABLISHED FEDERAL MAXIMUM CONTAMINANTLEVELS (MCL's) ARE CONTOURED. THE AREAINSIDE EACH CONTOUR EXCEEDS THE MCL.

2. ONLY DATA OBTAINED DURING Rl SAMPLINGACTIVITIES, AND INFERRED TO BE ASSOCIATEDWITH THE HATCHCO PLUME ARE CONTOURED.

3. CONTOURS ARE DRAWN APPROXIMATELY.

4. RISK BASED CONCENTRATIONSFOR COPC'S FOR WHICH NO MCL E)INCLUDE: NAPTHALENE-6.5 ug/L -ONLY NAPTHALENE OCCURED ABOVE


Contour Map

v Focu(HATCHCO) wcs Hatch co

WoodsJ Cross, Utah

(HAZARD INDEX=1) WERE CALCULATEDISTS. THE COPC AND RISK BASED CALCULATIONS

1.2.4-TRIMETHYLBENZENE-12 ug/LTHE RISK BASED LEVEL (STATIONS 104 AND 64).

Showing Areas ExceedingFederal Maximum Contaminant LevelsIn The Shallow Aquifer

ed Feasibility Study

Date

MARCH 2004

Figure

2-22

N

All NO

DPS-11.0-030All NO

140

DPS-ICtt-0161.2,4- TrimettiylbenzeneEthylbenzeneNaphthalenen— Propylbenzene

0.0540.0510.3650.530

DPS-I01.-026All ND

DPS-OBZ-016EthylbenzeneIsopropylbenzeneNaphthalenen-Propyl benzenesec—Butyl benzene

0.562.308.25

17.9611.4'

DPS-OB?-0201.2.4— Trimethytbenzenecis— 1.2- Dichloroethenem—Xylene and p—XyleneNaphthaleneTetrochloroetheneTrichloroethene

0.5846.240.564.630.93

90.95

D>

t)

Ifx

301

o

•"•= i5 <NSo

c10 t

.O

O IO) _O _.

a. o

LULUCCh-co

COLU

OOCO

DPS-0 64-0201 ,3,5— Trimethylbenzene4— IsopropyttolueneEthylbenzeneIsopropylbenzenem— Xylene and p-Xylenen— Propylbenzenesec-Butyl benzenetert-ButylbenzeneToluene

74.71339.01430.57489.83335.80867.768

161.83213.017

1.890

DPS-06I.-OZ5All ND

DPS-06i-035cis- 1 ,2-DichloroetheneTrichloroetheneVinyl Chloride

0.0330.0210.003

\

L

1.2.4— Trimethylbenzene1.3.5— Trimethylbenzene4- Isopnopyltoluenecis- 1,2- DichloroetheneEthylbenzeneIsopropylbenzenem—Xylene and p-XyleneNaphthaleneo-XyleneTetrochloroetheneTolueneTrichloroothene


LEGEND:INFERREDPOTENTIAL SOURCEAREA(TCE CONCENTRATION£ 60 ug/Kg)

HATCHCO PROPERTYBOUNDARY

418

ND

SUBSURFACE SOILSAMPLING LOCATION

NON-DETECT

Napthtalene 0.567 I18 ^^[DPS-OIS-OII I ' ' ' |&£^_ \ All ND

700 SOUTH STREET


DpS_064-020 SAMPLE ID (LAST 2DIGITS DENOTESAMPLE DEPTH)

CONTOUR - 10ug/l SOIL GAS(25' DEPTH)

NOTES:1. ALL CONCENTRATIONS ARE

IN mg/kq.

2. ONLY ANALYTICAL RESULTSEXCEEDING DETECTION LIMITSARE PRESENTED.

Inferred Potential Source AreaDate

MARCH 2004

! «/ UMTnunn\ Focused Feasibility StudyI HAIUHbU WS Hatch Co.

Woods Criss, Utah

Figure

7-1

GEOCOMPOSITE(UPPER)

1' PROTECTIVESOIL COVER

60 MILLDPE GEOMEMBRANE

SLOPE :

\

GEOTEXTILE(LOWER) PROPOSED

SUBGRADE

ANCHOR TRENCHCOMPACTED BACKFILL-(TYPE 2 GEOTEXTILE/

GCL/HDPE)

SnLCLO


CAP LINER SYSTEM

ûnrnun^ Focused Feasibility Study(JWTCHCOjw.S. Hatch Co.

Woods Cross, Utah

Dote

MARCH 20O

Figure

7-2

LJJLUtrCO

COHI

oo00

140

WELL SCHEMATIC

700 SOUTH STREET

OFF-GASDISCHARGE


Soil Vapor Ext

Woods C


LEGEND:

41©

INFERREDPOTENTIAL SOURCEAREA

HATCHCO PROPERTYBOUNDARY

SUBSURFACE SOILSAMPLING LOCATION

SOIL VAPOREXTRACTION WELL

OFF-GASCOLLECTIONMANIFOLD

action SystemDate

MARCH 2004

Feasibility Study:hCo.>ss, Utah

Figure

7-3

EFFLUENT CONTROLPANEL

FLOW METER

HYDROXYL PHOTOSTACK

STAINLESS STEEL UV-REACTOR

(16 KW)

METERING

I PUMP

HYDROGEN

PEROXIDE

INFLUENTPUMP

INLET

FROM MANIFOLD

EQUALIZATIONTANK


GROUNDWATER EXTRACTIONUV OXIDATION SYSTEMSCHEMATIC DIAGRAM

CHATCHCO)^TSHeatc

FhTo'b"lty study

Date

MARCH 2004

Woods Cross, Utah

Figure

7-4

PARTICLE TRACKING PATHLINES

WITHOUT PUMPINGPARTICLE TRACKING

WITH PUMPING (APPROX

APPROXIMATE SOUTHERN EXTENT-OF NORTHERN PLUME

APPROXIMATE SOUTHERN EXTENTOF NORTHERN PLUME f

FLOW DIRECTION / FLOW DIRECTION ,

NOTE: SOME PAT LINES REMOVED FOR CLARITY

XW-1

LEGEND

PARTICLE START POINT FORPARTICLE TRACKING ANALYSIS

PARTICLE PATHLINE

PROPOSED EXTRACTION WELL

HATCHCO BOUNDARY

TOTAL CHLORINATED HYDROCARBONISOCONCENTRATION CONTOUR (mg/L)


Groundwater FParticle Tracking

HATCHCOWoods

PATHLINES

. 3 gpm)

)w ModelAnalysis

Data

MARCH 2004

d Feasibility Studytch Co.ross, Utah

Figure

8-1

Appendix ATechnical Memorandum on Applicability of Monitored

Natural Attenuation- •

W.S. Hatch Co. HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

ONE COMPANY | Many Solutions'

March 23, 2004

Mr. Russ LeclercRegion 8 EPA999 18th Street, Ste. 500Denver, CO 80202

Re: Justification for Monitored Natural Attenuation RemedyHatchco Site

Dear Russ:

This letter supplements the Focused Feasibility Study (FFS) of the Hatchco Site in Woods Cross,Utah (the Site) and provides technical justification for Alternative 2 (Monitored NaturalAttenuation (MNA) with Institutional Controls) beyond that presented in the FFS. The letter isreferenced in the Draft FFS as Appendix A and will be included in final version of the FFS.

Hatchco reviewed the MNA Guidance - OSWER Directive 9200.4-17P (the Guidance) in detailand believes Site conditions and information provided in the Remedial Investigation (RI) Reportsupport an MNA remedy.

The Guidance identifies several criteria that should be met in order to select the MNAAlternative. These criteria are listed below (Guidance page citation provided) with acorresponding discussion of how the site conditions either meet or do not meet the criteria. Textfrom the Guidance is shown in normal type with Hatchco's discussion provided in italics.Several comments on the Remedial Alternatives Technical Memorandum were received from .Utah DEQ regarding the applicability of a MNA remedy. Responses to those Utah DEQcomments not included in the Guidance are provided at the end of this letter.

1. Time Frame - The time frame for MNA should be reasonable when compared with thatoffered by more active methods (Pgs. 3, 19).

The time frames to achieve groundwater remedial action objectives (RAO's) under anMNA remedy and active remediation were estimated using contaminant transportmodeling. Under a MNA remedy, the time frame to achieve groundwater RAO's in on-and off-Site is 24 to54 years, respectively. RAO's would be met in the on-Site area firstand the off-Site area shortly thereafter.

The contaminant transport model predicts that groundwater RAO's will be met in off-siteareas under the most aggressive remedial alternative being considered (pump and treatAlternatives 7a through 7c) in 14 years. The potential leaching of diffuse vadose zonecontamination to the water table considered under the MNA remedy is possible underAlternatives 7a through 7c. Therefore, action alternatives may require more than 14years to maintain water quality in off-Site areas and to achieve groundwater RAO's inon-Site areas. In addition, the presence of two overlapping plumes originating

Final - Technical Memorandum - Hatchco SiteMarch 23, 2004Page 2

from off-Site locations may preclude groundwater use in the area even if the groundwatercontaminant plume originating from the Hatchco Site is aggressively remediated.

2. Potential for Migration - EPA generally expects that MNA will only be appropriate for sitesthat have a low potential for contaminant migration (Pg. 3).

Computer simulations and other analyses indicate that the current horizontal extent ofcontamination is greater than in the future even under the MNA alternative.

3. Transformation Products - The potential for creation of toxic transformation products is morelikely to occur at non-petroleum sites (e.g., chlorinated solvents or other volatile organic spillsites) and should be evaluated to determine if implementation of an NMA remedy isappropriate and protective in the long term (Pg. 6).

Natural degradation ofperchloroethene (PCE) and tricloroethene (TCE) results in oneintermediate decay product (vinyl chloride) with a higher toxicity than the parentchemical. However, the ultimate decay products are non-toxic. Computer simulationsand other analyses indicate that the current horizontal extent of contamination (includingvinyl chloride) is greater than in the future even under the MNA alternative.

4. Cross Media Transfer - Processes that result in degradation of contaminants are preferable tothose which rely predominantly on the transfer of contamination from one medium toanother.. MNA remedies involving cross-media transfer of contamination should include asite-specific evaluation of the potential risk posed by the contaminants once transferred to aparticular medium (Pg. 6).

Contaminant transport model sensitivity analyses indicate biological or othercontaminant degradation mechanisms dominate in groundwater over those that fixatecontaminants to the aquifer matrix. Therefore, reduction in contaminant concentrationsin groundwater occurs primarily through the destruction of the contaminants in-situ.

Two cross media transfer mechanisms may be occurring and may continue to occurunder an MNA remedy. These include:

-- Partitioning of contaminants dissolved in groundwater into soil gas in theoverlying vadose zone. However, the Baseline Risk Assessment demonstrated thepotential risks posed by contaminants in soil gas are below a level of concern.

- Leaching of contaminants from the vadose zone to the water table. This processmay be occurring and may continue unless the MNA remedy included somesource control component such as that contemplated under Alternative 3(capping) or Alternative 4 (soil vapor extraction). However, the implementationof an institutional control restricting on- and off-Site groundwater use wouldminimize the risk of human exposure during the course of the MNA remedy.

Final - Technical Memorandum - Hatchco SiteMarch 23, 2004,Page 3

5. Hydrologic and Geochemical Conditions - Hydrologic and geochemical conditions favoringsignificant biodegradation of chlorinated solvents sufficient to achieve remediation

' objectives within a reasonable time frame are anticipated to occur only in limitedcircumstances (pg. 7).

Dechlorination of the more highly chlorinated compounds, such as PCE and TCE isoccurring. The presence of relatively high concentrations ofcis-1, 2-dichloroethene(DCE) and VC in on-Site groundwater (Attachment A) is evidence that reductivedechlorination of a parent compound (PCE or TCE) is taking place. Also, the existence of1,1-dichloroethane (DCA), in on-Site groundwater is further evidence that breakdown ofa more highly chlorinated parent compound (1,1,1-trichloroethane) is occurring at theSite.

6. Disadvantages of MNA - The potential disadvantages of MNA are listed on Page 10 of theGuidance and include:

a) Longer time frames to achieve remediation goals - Computer simulations suggest thatRAO's will be met in off-Site groundwater in 14 years under the most aggressiveremedial alternatives considered for the Site (pump and treat). However, activeremediation may,be required beyond this time frame in order to maintain off-Sitegroundwater quality while on-Site groundwater and soil conditions approach RAO's.Under a MNA remedy, on-and off-Site RAO's are estimated to be reached in 24 to 54years. However, the presence of two overlapping plumes originating, from off-Sitelocations may preclude groundwater use in the area even if the groundwatercontaminant plume originating from the Hatchco Site is aggressively remediated.

b) Site characterization will be more costly and complex - Site characterization is• thorough and complete and provides sufficient information to support the selection of

an MNA remedy.

c) Toxicity and/or mobility of transformation products may exceed that of the parentcompound - Natural degradation of some of the COCs (PCE and TCE) results in oneintermediate decay product (vinyl chloride) with a higher toxicity than the parentchemical. However, the ultimate decay products are non-toxic. Computer simulationsand other analyses indicate that the current horizontal extent of contamination isgreater than in the future even under a MNA remedy.

d) IC's may be necessary to ensure long-term protectiveness - This is true for allremedial alternatives as off-Site groundwater is predicted to meet RAO's in not lessthan 14 years under any remedial alternative.

e) The potential exists for continued migration and cross-media transfer of contaminants. - Computer simulations indicate that the groundwater contaminant plume is currently

at its maximum horizontal, extent. Attenuation mechanisms primarily destroycontaminants as they migrate from the Site. Cross-media transfer of contaminants


will occur under the MNA and several of the active remedies. However, the risksposed by this transfer have been quantified and are below a level of concern so longas an institutional control restricting on- and off-Site groundwater use isimplemented.

f) Hydrologic and geochemical conditions at the site may change with time leading torenewed mobility of stabilized contaminants - The primary contaminant attenuationprocess is biological destruction. Therefore, re-mobilization of stabilizedcontaminants is not a significant concern. Should site conditions change such thatMNA is not considered effective, the contingency remedy required under the MNAguidance will be implemented.

g) More extensive education and outreach efforts may be required - The need to engagethe community will primarily focus on the institutional control restrictinggroundwater use until RAO's are achieved. This institutional control will be requiredunder any remedial alternative.

1. Consideration or selection of MNA as a remedy or remedy component does not in any waychange or displace the following remedy selection principals (Pg. 12):

a) Source control measures should use treatment to address "principal threat" wasteswhenever practicable, and engineering controls for wastes that pose a relatively lowlong-term threat, or where treatment is impracticable - No principal threat wasteswere identified during the remedial investigation. Source removal measures wereimplemented prior to initiation of the RI/FFS. Engineering controls such as cappingare considered in the FFSfor contaminated vadose zone soils.

b) Contaminated groundwaters should be returned to "their beneficial uses whereverpracticable, within a time frame that is reasonable given the particular circumstancesof the Site." When restoration of groundwater is not possible, EPA "expects to .prevent further migration of the plume, prevent exposure to the contaminatedgroundwater, and evaluate further risk reduction." - Under the MNA remedy,groundwaters will be returned to their beneficial uses within a reasonable timeframe. Computer simulations indicate that the plume is currently at its maximumhorizontal extent. Therefore, under the MNA remedy, the groundwater contaminantplume is not expected to expand beyond its current limits.

c) Contaminated soils should be remediated to achieve an acceptable level of risk tohuman and environmental receptors, and to prevent transfer of contaminants to othermedia that would result in an unacceptable risk or exceed required clean-up levels. -

Current levels of soil contamination present a risk to humans below a level ofconcern and no environmental receptors have been identified. The potential fortransfer of contamination from vadose zone soils to groundwater will not result in

Final - Technical Memorandum - Hatchco SiteMarch 23, 2004PageS

unacceptable risk given the inclusion of an institutional control restrictinggroundwater use.

d) Remedial action in general should include opportunity for public involvement thatserve to both educate interested parties and to solicit feedback concerning thedecision making process. - EPA and UDEQ have coordinated communityinvolvement.

8. Decisions to employ MNA as a remedy or remedy component should be thoroughly andadequately supported with Site-specific characterization data and analysis. Sitecharacterization for natural attenuation generally warrant a quantitative understanding of thefollowing aspects of the Site (Pg. 13V.

a) Source mass - this was quantified and presented in Appendix K of the final RI Report.

b) Groundwater flow including preferential pathways - the hydrogeology of the Site andsurrounding area has been thoroughly characterized and a calibrated hydrauliccomputer model has been developed.

c) Contaminant phase distribution and partitioning between soil, groundwater and soilgas - contaminant partitioning between soil and soil gas and between groundwaterand soil gas was quantified with the Johnson and Ettinger model. Partitioningbetween groundwater and soil (aquifer matrix) was quantified through total organiccarbon and clay speciation analyses of aquifer matrix samples and corresponding usein computer simulations of contaminant transport in groundwater.

d) Rates of biological and non-biological transformation - biological transformationrates were quantified in three ways including; 1) Natural Attenuation ScreeningProtocol (EPA, 1998)1; 2) Buschek/Alcantar Method (1995)2 and; 3) throughcalibration of the contaminant transport model. Non-biological transformations wereaccounted for during calibration of the contaminant transport model.

e) Efficacy of MNA via numerical simulations of complex attenuation processes - such .numerical simulations have been performed and provide the estimated time framesfor achieving RAO's and time dependent ground water plume characteristics.

9. Estimate Remediation Time and Rate of Attenuation - Collect Site-specific data sufficient toestimate with an acceptable level of confidence both the rate of attenuation and theanticipated time required to achieve remediation objectives. A three-tiered approach to suchan evaluation is becoming more widely practiced and includes (Pgs. 15/16):

1 United States Environmental Protection Agency. 1998. Technical Protocol for Evaluating Natural Attenuation ofChlorinated Solvents in Ground Water EPA/600/R-98/128. Office of Research and Development.Washington, DC: Government Printing Office.

2 Buschek, T. E., and C.M. Alcantar. 1995. Regression Techniques and Analytical Solutions to DemonstrateIntrinsic Bioremediation. In Intrinsic Bioremediation. R.E. Hinchee, J.T. Wilson and D.C. Downey, Ed.Battelle Press. Columbus , OH


- Historical groundwater data demonstrating decreasing contaminant mass orconcentration over time at appropriate monitoring points.

- Data used to demonstrate indirectly the types of attenuation active at the site, and rateof attenuation.

- Data which directly demonstrate the occurrence of attenuation.

Remediation times and attenuation methods have been quantified through computer. simulation and other methods using Site-specific analytical and other data. Four quarters

of groundwater quality data were collected as part of the RI. The data quantity isinsufficient to demonstrate strong water quality trends. However, these data suggeststable water quality conditions over the time scale of a single year.

It is important to note that the "three tiered approach " has become "more widelypracticed" but is not required or even recommended. Therefore, the first of the threetiers, observing reduced contaminant mass or groundwater concentrations is notrequired. The Guidance elaborates further on Pg. 19 to say that unless EPA determinesthat historical data are of sufficient quality and duration to support a MNA decision, theTier 2 data requirement should be provided and where they are inadequate, the datarequirements of Tier 3 should be provided. This suggests that the results of Tier2 and 3analyses may supercede Tier 1 data when it is insufficient.

The second and third tier of the approach has been met. Computer simulationsconsidered both indirectly and directly measured attenuation mechanisms.

10. Criteria Where MNA May Be Appropriate - On Pages 17 and 18 the Guidance lists criteriathat should be considered when deciding if MNA is appropriate, including:

a. Will contaminants be remediated by-natural attenuation processes? - RAO's will bereached through natural attenuation processes inferred from Site-specific analyticaland other data.

' b. Is the contaminant plume stable? - Computer simulation show the aerial extent of theplume is currently at its maximum extent and is expected to shrink under an MNAremedy.

c. Will human health, drinking water supplies, or other environmental media beadversely impacted under the MNA alternative? - An institutional control restrictingon- and off-Site groundwater use will be required under an MNA remedy, as well asall remedial alternatives considered in the FFS. The institutional control willminimize the potential for human exposure to groundwater.

d. Consider the current and projected demand for the affected resource over time - 77?ereis no known groundwater use within the contaminant plume attributable to the


Hatchco Site and municipal water supply wells are remote from the plume. However,the use of contaminated groundwater will not be known with certianty until EPAcompletes work on portions of the NPL Site surrounding the Hatchco study area.Future demand for groundwater in the shallow aquifers has not been assessed.However, the presence of widespread groundwater contamination in the NPL Siteoriginating from multiple sources suggests that groundwater use restrictions areunavoidable.

e. Will the contamination exert a long-term detrimental impact on water supplies? - AsAbove

f. Is the estimated remediation timeframe reasonable compared to other, more activeremediation'alternatives? - Computer simulations suggest that RAO's will be met inoff-Site groundwater in 14 years under the most aggressive remedial alternativesconsidered for the Site (pump and treat). However, active remediation may berequired beyond this timeframe in order to maintain off-Site groundwater qualitywhile on-Site groundwater and soil conditions approach RAO's. Under a MNAremedy, on-and off-Site RAO's are expected to be reached in 24 to 54years.

g. Have the sources of contamination been adequately controlled? - Many sources ofcontamination were remediated through excavation and on-Site treatment or off-Sitedisposal prior to the remedial investigation. Remaining potential source material islimited to diffuse, low-level contamination ofvadose zone soils at depths between 9and 20 feet. Further source control measures may include capping to minimize futurecross-media transfer of contaminants.

h. Will transformation products present a greater risk? - Natural degradation of some ofthe COCs (PCE and TCE) result in an intermediate decay product (vinyl chloride)with a higher toxicity than the parent chemical. However, the ultimate decay productsare non-toxic. Computer simulations and other analyses indicate that the currenthorizontal extent of contamination is greater than in the future even under the MNAalternative. Therefore, future conditions under an MNA remedy are expected to resultin lower risks.

i. Will other Site remedial actions adversely impact the MNA remedy component? -Active pumping of groundwater may change the size and location of an overlappingcontaminant plume inferred to originaefrom an off-Site location to the north of theHatchco Site. This may affect the natural attenuation of contamination hydraulicallydown-gradient of the Hatchco Site. No other remedial actions are contemplated thatmay adversely affect an MNA remedy.

j. Is it possible to implement IC's? - The local municipality would enforce theinstitutional control. However, the institutional control would be required under anyalternative. Therefore, this criterion is not applicable to the MNA selection process.

Final - Technical Memorandum - Hatchco SiteMarch 23, 2004PageS

11. Use of Source Controls - EPA expects that MNA will be most appropriate when used inconjunction with other remediation measures (Pg. 17).

Many sources of contamination were remediated through excavation and on-Sitetreatment or off-Site disposal prior to the remedial investigation. Remaining potentialsource material is limited to diffuse, low-level contamination ofvadose zone soils atdepths between 9 and 20 feet. Further source control measure may include capping tominimize future cross-media transfer of contaminants.

12. Acceptable Environmental Impacts - MNA should not be used where such an approachwould result in either plume migration or impacts to environmental resources that would beunacceptable to the overseeing regulatory authority. Therefore, sites where the contaminantplumes are no longer increasing in extent or are shrinking would be the most appropriatecandidates for MNA (Pg. 18).

No environmental impacts 'were identified during the.remedial investigation.

Responses to Specific Utah DEQ Comments:

1. A statistical evaluation of natural attenuation rates at other sites indicated "a measureddecrease in contaminant concentrations of at least one order of magnitude" is necessary todetermine appropriate rate law to describe the rate of attenuation.

Computer model calibration to refine the rate law constant involved a source term of'1,000 ug/l ofTCE and down-gradient TCE concentrations as low as 49 ug/l.

1. In the draft RI Report a potential MTBE commingled source was mentioned and it shouldbe noted that MTBE tends not to degrade readily in the subsurface and has been found tomigrate large distances and threaten down-gradient water.

The MTBE plume originates at an off-Site location to the north of the Hatchco Site.Therefore, remediation of the MTBE plume is not Hatchco's responsibility.


3. In assessing the implementation of MNA the guidance states a concern where there iscommingled petroleum and chlorinated solvent contamination. Degradation of thechlorinated solvents is achieved, in part, through action of microbes that derive theirenergy from the carbon in the petroleum. Removal of the petroleum removes some of thesource food for these microbes and the rate of degradation of the chlorinated solvents isdecreased.

Estimates of contaminant degradation rates were made using data from locationswithin the plume where MTBE was absent. AfTBE occurred only in Hatchco wellsUS and 4S (Attachment A).

We hope this letter helps to clarify the applicability of MNA as the primary or sole remedy forthe Hatchco Site. We look forward to working with you and Utah DEQ on the remedy selectionprocess. If you have any questions or require additional information, please contact me at (303)764-1549.

Sincerely,HDE ENGINEERING,

Kenneth NaProject Manager

Attachment

cc. Mark Davis - HatchcoKevin Murray - LeBoeuf, LambMichael Storck - Utah DEQ

Appendix BCosting

W.S Hatch Co HDR Engineering, IncFocused Feasibility Study Final Report July 2004

Remedial Alternative Costing

Cost estimates developed at the detailed analysis of alternatives phase of the FFS shouldhave accuracy ranges of-30% to +50% (EPA, 2000). These cost estimates are used tocompare alternatives and support remedy selection. Cost estimates at this stage areintended to provide a measure of total resource costs over time associated with any givenalternative.

The types of costs that are assessed include the following:

• Capital costs• Annual operations and maintenance costs• Periodic costs• Net present value of capital, O&M and periodic costs.

EPA guidance (EPA, 2000) requires the use of a 7% discount factor when calculating netpresent value of capital, operation and maintenance costs for all non-Federal Facilities.

W.S. Hatch Co Draft Focused Feasibility Study

Alternative 2MONITORED NATURAL ATTENUATION VWINSTITUTIONAL CONTROLS

Site: HatchcoLocation: Woods Cross, UTPhase: FS (-30% to +50%)Base Year: 2003Date: 14-Jul-03

Description:Alternative 2 consists of monitored natural attenuation. Also includes institutionalcontrols. Captial costs occur in Year 0. Annual O&M costs occur in Years 1-30.

CAPITAL COSTS: IDescription

Monitoring Well InstallationAdditional Monitoring WellsMiscellaneous (Well Development, etc.)SUBTOTAL

SUBTOTAL

Contingency

SUBTOTALProject ManagementRemedial DesignConstruction Management

Qty Unit

40 LF1 EA

25%

10%20%15%

Unit Cost Total Ref. Notes

$50.00 $2,000 a$500.00 $500 b

$2,500

$2,500

$625 c 1 0% Scope + 1 5% Bid

$3,125$313 c$625 c$469 c

Institutional ControlsGroundwater Use Restriction 1 LS $5,000.00 $5,000 c Legal fees

TOTAL CAPITAL COST

•• ^^^^^ ••• • ^^ • • ••• ^^^^^^ ••M^^^^^^^^^^^^^M

I $9,531 1

ANNUAL O&M COSTS:Description

Site MonitoringGroundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

SUBTOTAL

Contingency

SUBTOTALProject ManagementTechnical Support

TOTAL ANNUAL O&M COST

Qty Unit Unit Cost Total Ref.

16 hrs $75.00 $1,200 b12 EA $150.00 $1,800 b

$3,000

$3,000

25% $750 c

$3,75010% $375 C15% $563 c

| $4,68&|

Notes

1-day, semi-annual sampling6-samples, semi-annually

PRESENT VALUE ANALYSIS: |

DescriptionCapital CostAnnual O&M Cost

Total Cost Discount PresentYear Total Cost Per Year Factor (7%) Value Ref.

0 $9,531 $9,531 1 $9,5311-30 $140.625 $4,688 12.409 $58,167

Notes

$150,156 $67,698

TOTAL PRESENT VALUE OF ALTERNATIVE 2: $67,698|


W S. Hatch Co Draft Focused Feasibility Study

1 Alternative 3 ,1 SURFACE CAPPING W/INSTITUTIONAL CONTROLS

Site HatchcoLocation Woods Cross, UTPhase. FS (-30% to +50%)Base Year: 2003Date- 14-Jul-03

Description.Alternative 3 involves installation of a low-permeability barrier of the source area Also includesinstitutional controls Captial costs occur in Year 0. Annual O&M costs occur in Years 1-30.

• CAPITAL COSTS: IDescription

Surface CappingSoil Excavation/Placement/CompactionGeomembrane Liner and PlacementDust ControlSeedingSUBTOTAL

Monitonng Well InstallationAdditional Monitonng WellsMiscellaneous (Well Development, etc.)SUBTOTAL

SUBTOTAL

Contingency


Institutional ControlsGroundwater Use Restriction

TOTAL CAPITAL COST

Qty

1,9602,335

50.5

401

25%

10%20%15%

1

Unit Unit Cost

CY $7.95SY $11.30M-gal $21.86acre $3,580.00

LF $50 00EA $500.00

LS $5.000.00

. [

Total Ref.

$15,582 d$26,386 e

$109 e$1,790 d

$43,867

$2,000 a$500 b

$2,500

$46.367

$11,592 c

$57,959$5,796 c

$11,592 c$8,694 c

$5,000 c

$89,04o|

Notes

10% Scope + 15% Bid

Legal fees

ANNUAL O&M COSTS: 1Description

Site MonitoringGroundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

SUBTOTAL

Contingency



Qty

1612

25%

10%15%

Unit Unit Cost

hrs $75 00EA $150 00

[

Total Ref.

$1,200 b$1,800b$3,000

$3,000

$750 c

$3.750$375 c$563 c

$4.688|

Notes

1-day, semi-annual sampling6-samples. semi-annually

PRESENT VALUE ANALYSIS: 1

Description YearCapital Cost 0Annual O&M Cost 1-30

TOTAL PRESENT VALUE OF ALTERNATIVE 3:

Total Cost$89,040

$140,625$229,665

Total Cost DiscountPer Year Factor (7%)

$89,040 1$4,688 12.409

[

PresentValue Ref.$89.040$58.167

$147,207

$147.2071

Notes

HDR Engineering, Inc

WS Hatch Co

Alternative 4SOIL VAPOR EXTRACTION W/INSTITUTIONAL CONTROLS

Draft Focused Feasibility Study

Site MatchcoLocation Woods Cross, UTPhase FS (-30% to +50%)Base Year 2003Date 14-Jul-03

DescriptionAlternative 4 consists of soil vapor extraction to treat soil in the source area Also includesinstitutional controls Captial costs occur in Year 0 Annual O&M costs occur in Years 1-5 Periodiccosts occur in years S through 10

1 CAPITAL COSTS:Description

Vapor Extraction Point InstallationMobilization/DemobilizationWell InstallationMiscellaneous (Well Development, etc )Vapor Collection Piping (4*)SUBTOTAL

Soil Vapor Extraction Equipment5 6 HP Positive Displacement BlowerElectrical HookupSUBTOTAL

Monitoring Well InstallationAdditional Monitoring WellsMiscellaneous (Well Development, etc JSUBTOTAL

SUBTOTAL

Contingency



TOTAL CAPITAL COST

Qty Unit

1 LS120 LF

4 EA300 LF

1 EA1 LS

40 LF1 EA

25%

10%20%15%

1 LS

Unit Cost

$ 5.853 50$ 5000$ 500 00$ 701

$1.69200$10,000 00

$5000$50000

$5,000 00

I

Total Ref.

$2,709 d$6,000 d$2,000 b$2,103 d

$12,812

$1,692 d$10,000 a$11,692

$2,000 b$500 b

$2,500

$27,004

$6,751 c

$33.755$3,376 c$6,751 c$5,063 c

$5.000 c

$53,945|

Notes

10% Scope + 15% Bid

Legal fees

I ^ ^ H^ ^ ^ ^ HMManaMMBiMM^ H^ H

1 ANNUAL O&M COSTS:• •••• ^ ^ ^ • ••• ••• ^ ^ • •••••• ^ ^ ^ HDescription

Electric ConsumptionInspection/Maintenance/RepairSUBTOTAL

Site MonitoringSVE Off-gas SamplingSVE Off-gas Laboratory AnalysisGroundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

SUBTOTAL

Contingency



Qty Unit37000 KWH

96 hrs

16 QTR4 EA

18 hrs12 EA

25%

10%15%

Unit Cost$006

$75.00

$7500$22200$7500

$15000

I

Total Ref.$2,220$7,200$9,420

$1,200 b$868 d

$1,200 b$1,800 b$5,088

$14,508

$3,627

$18,135$1,814$2.720

$22,669|

Notes

8 man-hours per month

4-hours/quarter w/1-man crew1 sample/quarter1-day, semi annual sampling6-samples, semi-annually

PERIOD C COSTS: 1Description Year

SVE Well Abandonment 5

Continued Groundwater Monitoring 6-10Groundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

Qty Unit120 LF

16 hrs12 EA

Unit Cost$31 16

$7500$15000

Total Ref.$3,739 d

$1,200 b$1,800 b$3,000

Notes

1-day, semi annual sampling6-samples, semi-annually


Description YearCapital Cost 0Annual O&M Cost 1-5Periodic Cost 5Periodic Cost 6Periodic Cost 7Periodic Cost ' 8Periodic Cost 9Periodic Cost 10

|FTOTAL PRESENT VALUE OF ALTERNATIVE 4:

Total CostTotal Cost Per Year

$53,945 $53.945$113,344 $22,669

$3,739 $3,739$3.000 $3,000$3,000 $3,000$3,000 $3,000$3,000 $3,000$3,000 $3,000

$186,028

DiscountFactor (7%)

14 1

07130.66606230.58205440508

I

PresentValue Ref.$53,945$92,942$2,666$1,998$1,869$1,746$1,632$1,524

$158,322

$158.322]

Notes


WS Hatch Co Draft Focused Feasibility Study

(Alternative EENHANCED IN-SITU BIOREMEDIATION W/INSTITUTIONAL CONTROLS

Site HatchcoLocation Woods Cross. UTPhase FS (-30% to +50%)Base Year 2003Date 14-Jul-03

DescnptionAlternative 6 consists of enhanced m-silu bioremediation to Ireat groundwater in the source areaAlso includes institutional controls Captial costs occur in Year 0 Annual O&M costs occur inYears 1-15 Periodic costs occur in years 2, 4, 6, and 8

^^^^^^^^^^^^_aaa^^^_^^^^^^_^^^^^_^^^^_^^^^^_^^^^^^^^^^^_l ^_^^^^^^_^^^^^^H^H ll>M|• CAPITAL COSTS:Description

HRC InjectionMobilization/DemobilizationDirect Push Delivery (-210 points)HRC MaterialSUBTOTAL

Monitoring Well InstallationAdditional Monitoring WellsMiscellaneous (Well Development, etc )SUBTOTAL

SUBTOTAL

Contingency


Institutional ControlsGroundwater Use Restnctlon

TOTAL CAPITAL COST

Qty Unit

1 LS14 days

6.400 Ibs

40 LF1 EA

25%

10%20%15%

1 LS

Unit Cost

$1,11600$2,000 00

$575

$5000$500 00

$5.000 00

I

Total Ref.

$1.116 d$28,0001$48.300 ($77.416

$2.000 a$500 b

$2,500

$79,916

$19,979 c

$99.895$9,990 c

$19.979 c$14.984 c

$5.000 c

$149,848J

Notes

Assume -15 points/day

Legal fees

IO&M COSTS:Description

Site MonitonngGroundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

ContingencySUBTOTAL

Project ManagementTechnical Support


Qty Unit

16 Hrs12 EA

25%

10%15%

Unit Cost

$75.00$15000

I

Total Ref.

$1.200 b$1.800 b$3,000

$750 00 c$3,750 00

$375 00 c$56250 c

$4,687 50J

Notes

1-day, semi-annual sampling6-samples, sem-annually

1 PERIODIC COSTS: 1Description Year

HRC Injection 2Mobilization/DemobilizationDirect Push Delivery (-210 points)HRC MatenalReportingSUBTOTAL



HRC Injection 8Mobilization/DemobilizationDirect Push Delivery (-210 points)HRC MaterialReportingSUBTOTAL

Qty Unit

1 LS14 days

4.200 Ibs1 LS

1 LS14 days

2,100 Ibs1 LS

1 LS14 days

1.050 Ibs1 LS

1 LS14 days

525 Ibs1 LS

Unit Cost

$1. 11600S2.000 00

$600$4,000 00

$1.11600$2,000 00

$700$4,000 00

$1,11600$2.000 00

$750$4,000 00

$1,11600$2.000 00

$750$4,000 00

Total Ref.

$1.116 a$28.000$25,200 b$4,000

$58,316

$1.116 a$28,000$14.700 b$4,000

S47.816

$1,116 a$28.000$7,875 b$4,000

$40,991

$1.116 a$28,000$3,938 b$4.000

$37,054

Notes


Description YearCapital Cost 0Annual O&M Cost 1-15Periodic Cost 2Penodic Cost 4Periodic Cost 6Penodic Cost 8

TOTAL PRESENT VALUE OF ALTERNATIVE 6:

Total Total CostCost Per Year

$149.848 $149.848$70,313 $4.668$58.316 $58,316$47,816 $47,816$40,991 $40.991$37,054 $37.054

$404.337

DiscountFactor (7%) Present Value Ref.

1 $149.8489 108 $42.6940 873 $50,9100 763 $36,4840 666 $27,3000.582 $21,565

I

$328.800

$328.BOo|

Notes


W.S Hatch Co Draft Focused Feasibility Study

Site: HatchcoLocation. Woods Cross, UTPhase FS (-30% to +50%)Base Year. 2003Date 14-Jul-03

Description.Alternative 7a consists of groundwater extraction with air stripping to treat Site groundwaterAlso includes institutional controls. Captial costs occur in Year 0. Annual O&M costs occur inYears 1-15 Periodic costs occur in years 15-20

I CAPITAL COSTS:Description

Extraction Well InstallationMobilization/DemobilizationExtraction Well InstallationMiscellaneous (Well Development, etc.)Well Head ConstructionTrenching and PipingElectrical Upgrade to 3-PhaseSubmersible PumpSUBTOTAL

Air Stripping EquipmentMulti-Stage DiffuserPump Sump SystemControl PanelSUBTOTAL

Monitoring Well InstallationAdditional Monitonng WellsMiscellaneous (Well Development, etc )SUBTOTAL

SUBTOTAL

Contingency


Institutional ControlsGroundwater Use Restnction

TOTAL CAPITAL COST

•••• ^ • ^ •• ^ • ^ ••• • ^ ••••• ^ • ^ ^ ••• ^ ^ ^

Qty Unit

1 LS40 LF

1 EA1 EA

100 LF1 EA1 EA

1 EA1 EA1 EA

40 LF1 EA

25%

10%20%15%

1 LS

Unit Cost

$5,853.50$5000$500.00

$300.00$4500

$10,000.00$ 1,827.00

$5,775.00$1,25000$4,880 00

$50.00$500.00

$5,000.00

|

Total Ref.

$2,709 d$2,000 a

$500 b$300 a

$4,500 a$10,000 a$1,827 d

$21,836

$5,775 g$1,250 g$4,880 g

$11,905

$2,000 a$500 b

$2,500

$36,241

$9,060 c

$45,301$4,530 c$9.060 c$6.795 c

$5,000 c

$70,687

Notes

10% Scope* 15% Bid

Legal fees

ANNUAL O&M COSTS: I |Description

Electric ConsumptionInspection/Maintenance/RepairMiscellaneous PartsSUBTOTAL

Site MonitoringOff-gas SamplingOff-gas Laboratory AnalysisDischarge SamplingDischarge Laboratory AnalysisGroundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

SUBTOTAL

Contingency



Qty Unit50,000 KWH

96 Hrs1 LS

8 Hrs4 EA

24 Hrs12 EA16 Hrs12 EA

25%

10%15%

Unit Cost$0.06

$7500$500.00

$75.00$222.00$75.00

$15000$75.00

$150.00

I

Total Ref.$3,000$7,200

$500$10,700

$600 b$888 d

$1,800 a$1,8003$1,200 b

1800 b$8,088

$18.288

$4,572 C

$22,860$2,286 c$3,429 c

$28,575

Notes


2 hours/quarter w/1-man crew1 sample/month2 hours/month1 sample/month1-day, semi-annual sampling6-samples, semi-annually


W.S. Hatch Co

PERIODIC COSTS:Description

Extraction Well AbandonmentSUBTOTAL


Year15

Qty Unit40 LF

Unit Cost$31 16

Total Ref.$1,246 c

Notes

$1,246


16 hrs12 EA

$7500$150.00

$1,200b$1,800 b$3,000


^^^^^^^^^___MMHM^^^^^_^^^^^^^_^^^^^^_PRESENT VALUE ANALYSIS:

Total Cost Discount PresentDescription

Capital CostAnnual O&M CostPeriodic CostPeriodic CostPeriodic CostPenodic CostPeriodic Cost

TOTAL PRESENT VALUE OF ALTERNATIVE 7a:

Year0

1-151617181920

Total Cost$70,687

$428,625$3,000$3,000$3,000$3,000$3,000

Per Year Factor (7%)$70,687$28,575$3,000$3.000$3,000$3,000$3,000

191080.3390.31702960.2770258

Value Ref.$70,687

$260,261$1,017

$951$888$831$774

Notes

$514,312 $335,409

$335,409|


W S. Hatch Co. Draft Focused Feasibility Study

Alternative 7bON-SITE GROUNDWATER EXTRACTION W/TREATMENT VIA ULTRAVIOLET OXIDATION AND INSTITUTIONAL CONTROLS••• ^^^^^ • ^^^^^^^^^^^^^^^^ • ^^^^^^^^^^^^^^^^^^H^^^^V

Site- - HatchcoLocation: Woods Cross, UTPhase: FS (-30% to +50%)Base Year: 2003Date: 14-Jul-03

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ••••• ^K^^^^^^^^^^^^^^^H

Description:Alternative 7b consists of groundwater extraction with ultraviolet/oxidation treatment of Sitegroundwater. Also includes institutional controls. Captial costs occur in Year 0. Annual O&Mcosts occur in Years 1-15. Periodic costs occur in years 15-20.

^^^^^^^^ •• ^^^^^^^^^^^^^ • ^^^^^^^^^^^^^^^^^^^^^ •••• • • • ••• ^H| CAPITAL COSTS: I IDescription

Extraction Well InstallationMobilization/DemobilizationExtraction Well InstallationMiscellaneous (Well Development, etc.)Well Head ConstructionTrenching and PipingElectrical Upgrade to 3-PhaseSubmersible PumpHeated Equipment BuildingSUBTOTAL

UV/Oxidation Equipment

Monitoring Well InstallationAdditional Monitoring WellsMiscellaneous (Well Development, etc.)SUBTOTAL

SUBTOTAL

Contingency



TOTAL CAPITAL COST

^ ^ ^ ^MM^ B^ ^ B^B*HB^ BB^MMH^ ^ ^H^ ^ ^ ^HMH^ ^ ^ ^M

Qty Unit

1 LS40 LF

1 EA1 EA

100 LF1 EA1 EA

100 SF

1 EA

40 LF1 EA

25%

10%20%15%

1 LS

^^^^— — — — ^^^^^^^^«— ^^^—

Unit Cost

$5,853.50$5000

$500.00$300.00$45.00

$10,000.00$1.82700

$77.00

$ 88,900.00

$50.00$500.00

$5,000

|

•MMM^ ^ ^ ^ HMMM

Total Ref. Notes

$2,709 d$2,000 a

$500 b$300 a

$4,500 a$10,000 a$1,827 d$7,700 d

$29,536

$88,900 h System described in App

$2,000 a$500 b

$2,500

$120,936

$30,234 c 1 0% Scope + 1 5% Bid

$151,170$15,117 c$30,234 c$22,676 c

$5,000 c Legal fees

$224,197|

^^^^^^^^^^^^^ • ^ • •• ^^^ • ^^^ • ^^M| ANNUAL O&M COSTS: I IDescription

Electric ConsumptionHydrogen PeroxideUV LampsInspection/Maintenance/RepairMiscellaneous PartsSUBTOTAL

Site MonitoringDischarge SamplingDischarge Laboratory AnalysisGroundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

SUBTOTAL

Contingency



Qty Unit160,000 KWH

350 LB2 EA

120 Hrs1 LS


25%

10%15%

Unit Cost$0.06

$1,000.00$75.00

$500.00

$75.00$150.00$75.00

$150.00

I

Total Ref. Notes$9,600 d,h

$200 h$2,000 h$9,000 h 10 man-hours per month

$500 b$21,300

$1 ,800 a 2 hours/month$1,800 a 1 sample/month$1,200 b 1 -day, semi-annual sampling

1800 b 6-samples, semi-annually$6,600

$27,900

$6,975

$34,875$3,488$5,231

$43,594|


W.S. Hatch Co.PERIODIC COSTS:

DescriptionExtraction Well AbandonmentSUBTOTAL

Year15

Qty Unit40 LF

Unit Cost$31.16

Total Ref.$1.246 d


Notes

$1,246

f Continued Groundwater MonitoringGroundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

16-201612

hrsEA

$75$150

$1,200 b$1,800 b$3,000


| PRESENT VALUE ANALYSIS: |

DescriptionCapital CostAnnual O&M CostPeriodic CostPeriodic CostPeriodic CostPeriodic CostPeriodic Cost

Year0

1-151617181920

Total Cost$224,197$653,906

$3,000$3,000$3,000$3,000$3,000

$893,103

Total CostPer Year$224,197

$43,594$3,000$3,000$3,000$3,000$3,000

DiscountFactor (7%)

19.1080.3390.3170.2960.2770.258

PresentValue Ref.$224,197$397,052

$1,017$951$888$831$774

$625,709

Notes

TOTAL PRESENT VALUE OF ALTERNATIVE 7b: $625,709|


W S Hatch Co Draft Focused Feasibility Study

Alternative 7cON-SITE GROUNDWATER EXTRACTION W/DISCHARGE TO POTW AND INSTITUTIONAL CONTROLS

Site HatchedLocation Woods Cross, UTPhase FS (-30% to +50%)Base Year 2003Date 14-Ju!-03

DescriptionAlternative 7c consists of groundwater extraction with direct discharge to POTW Also includesinstitutional controls Captial costs occur in Year 0 Annual O&M costs occur in Years 1-15Penodic costs occur in years 15-20

• CAPITAL COSTS:Description

Extraction Well InstallationMobilization/DemobilizationExtraction Well InstallationMiscellaneous (Well Development, etc )Well Head ConstructionTrenching and PipingElectrical Upgrade to 3-PhaseSubmersible PumpSUBTOTAL

Monitoring Well InstallationAdditional Monitoring WellsMiscellaneous (Well Development, etc )SUBTOTAL

SUBTOTAL

Contingency



TOTAL CAPITAL COST

Qty Unit

1 LS40 LF1 EA1 EA

100 LF1 EA1 EA

40 LF1 EA

25%

10%20%15%

1 LS

Unit Cost

$ 5,85350$ 50.00

$500.00$ 300 00$ 4500$ 10,00000

$1 ,827 00

$5000$50000

$5.000

I

Total Ref.

$2,709 d$2,000 a

$500 b$300 a

$4,500 a$10,000 a$1,827 d

$21.836

$2,000 a$500 b

$2,500

$24,336

$6,084 a

$30,420$3,042 a$6,084 a$4,563 a

$5.000 a

$49,109|

Notes

10% Scope +15% Bid

Legal fees

ANNUAL O&M COSTS:Description

Electnc ConsumptionInspection/Maintenance/RepairMiscellaneous PartsSUBTOTAL

Site MonitoringDischarge SamplingDischarge Laboratory AnalysisGroundwater SamplingGroundwater Laboratory AnalysisSUBTOTAL

SUBTOTAL

Contingency



Qty Unit5000 KWH

48 Mrs1 LS


25%

10%15%

Unit Cost$006

$75$250

$7500$15000$7500

$15000

I

Total Ref.$300

$3,600$250

$4,150

$1,800 a$1,800 a$1,200 b$1,800 b$6,600

$10.750

$2,688

$13,438$1.344$2,016

$16,797|

Notes


2 hours/month1 sample/month1-day, semi-annual sampling6-samples, semi-annually

PERIODIC COSTS: 1Description Year

Extraction Well Abandonment 1 5SUBTOTAL


Qty Unit40 LF

16 hrs12 EA

Unit Cost$31 16

$75$150

Tout Ref.$1,246 a$1.246

$1,200 b$1,800 b$3,000

Notes


PRESENT VALUE ANALYSIS: 1^ ^ • ^ ^ • ^ ^ ^ ^ ^ • ••• ^ • ^ ^ ^ ^ ^ ^

Description YearCapital Cost 0Annual O&M Cost 1-15Penodic Cost 16Penodic Cost 1 7Penodic Cost 18Penodic Cost 19Penodic Cost 20

TOTAL PRESENT VALUE OF ALTERNATIVE 7c:

Total CostTotal Cost Per Year

$49,109 $49.109$251,953 $16.797

$3,000 $3,000$3,000 $3.000$3,000 $3.000$3.000 $3,000$3,000 $3.000

$316.062

DiscountFactor (7%)

1910803390317029602770258

I

^^^^ •Mi ^^^^^^H

PresentValue Ref.$49,109

$152,986$1.017

$951$888$831$774

$206.556

$206,556|

Notes

HDR Engineenng, Inc

References

a Wasatch Environmental price quote, see Appendix C-l.b Cost estimate based on best professional judgment.c EPA, 2000. A Guide to Developing and Documenting Cost Estimates During the

Feasibility Study. EPA 540-R-00-002.d RSMeans, 2002. Environmental Remediation Cost Data - Assemblies, 8th Annual

Edition.e Adjusted from HDR Costing in the California Gulch Superfund Site OU6 FFSf Regenesis Bioremediation Products price quote, see Appendix C-2.g Carbtrol Corporation price quote, see Appendix C-3.h Hydroxyl Systems, Inc. price quote, see Appendix C-4.

Appendix CVendor Information

WS Hatch Co HDR Engineering, IncFocused Feasibility Study Final Report July 2004

Appendix C is subdivided, by vendor, into the following five sections:

C-l Wasatch Environmental

C-2 Regenesis Bioremediation Products

C-3 Carbtrol Corporation

C-4 Hydroxyl Systems, Inc.

C-5 ARS Technologies, Inc.

W S. Hatch Co HDR Engineering, Inc.Focused Feasibility Study Final Report July 2004

Appendix C-lWasatch Environmental


McCormick, Allison M

From: Les Pennington [email protected]]

Sent: Thursday, June 19, 2003 3:30 PM

To: McCormick, Allison M

Subject: Re: FW: Hatchco Site Data

Allison,

Per your request for a cost estimate for seven 4-in dia wells about 40 feet deep, with connectingtrenching, and using pneumatic pumps:

Drilling and well installation (assurme 8'" auger, PVC screen) would cost about $50/ft.

Trenching should be easy, there is no asphalt or concrete paving to cut and replace....$40-50/ftdepending on type and amount of piping.

Each well head (assume 12 to 18-inch manhole), parts and assembly, about $300 each.

There is single phase power on a pole centrally located and near the west property line. Converting tothree phase would cost probably less than $10,000.

I will fax you information on air pumps. You can call Clean Environment 800-537-1767 for equipmentcost....once you decide what you need.

Appendix C-2Regenesis Bioremediation Products

W.S Hatch Co. HDR Engineering, IncFocused Feasibility Study Final Report July 2004

July 1, 2003 prop. OKL0203-205h

Allison McCormickHDR Engineering, Inc.303 E. 17th Avenue, Suite 300Denver, CO 80203Fax: (303) 860-7139

Subject: AcceleratiqnôfBiojemediation using HRC® at the Hatch Co. Site

Dear Ms. McCormick:

We have reviewed the information that you provided for the above-referenced site. In the followingsections, we provide design and cost information for a potential site remediation approach. Thisinformation should be considered preliminary since a number of assumptions have been madeconcerning site conditions and the extent of the contaminant plume requiring remediation. We lookforward to working with you to develop a specific strategy that meets your objectives.

Use of HRC to Accelerate Bioremediation

Hydrogen Release Compound (HRC) is used to enhance in situ biodegradation rates for chlorinatedhydrocarbons (CHs) by supporting anaerobic reductive dechlorination processes. Reductivedechlorination is now recognized as one of the primary attenuation mechanisms by which chlorinatedsolvent groundwater plumes can be contained and/or remediated.

HRC is a proprietary polylactate ester that, upon being deposited into the subsurface, slowly releaseslactate. Lactate is metabolized by naturally occurring microorganisms, resulting in the creation ofanaerobic aquifer conditions and the production of hydrogen. Naturally occurring microorganismscapable of reductive dechlorination then use the hydrogen to progressively remove chlorine atomsfrom chlorinated hydrocarbon contaminants (i.e. convert tetrachloroethene [PCE] to trichloroethene[TCE] to dichloroethene [DCE] to vinyl chloride [VC] to ethene).

HRC is manufactured as a viscous gel that can be injected into the saturated zone in a grid or barrierconfigurations for either localized area or cutoff-based treatment approaches. The use of HRC forgroundwater remediation offers a comparatively simple and cost effective remediation alternative forsites that would otherwise require unacceptably long periods of time for natural attenuation or thehigh levels of capital investment and operating expense associated with active remediationtechnologies.

June 30, 2003 Page 2 of 5

Use of HRC-X to Accelerate Bioremediation

HRC-X is a special formulation of HRC designed to last 2 to 3 years in the aquifer. HRC-X offers apassive, low-cost and effective approach to the remediation of chlorinated solvent impacted sitesincluding high concentration residual DNAPL sites. The use of HRC-X for groundwater remediationoffers a comparatively simple and cost effective remediation alternative for sites that would otherwiserequire unacceptably long periods of time for natural attenuation or the high levels of capitalinvestment and operating expense associated with active remediation technologies. In addition, theuse of HRC-X as a remediation strategy is ideal for sites with limited accessibility and/or pendingdevelopment plans.

Design/Proposal Assumptions

Using the information you provided, we have made the following assumptions to estimate systemdesign variables and dose amounts.

• Plume area requiring treatment: approximately 21,000 ft2

• Representative contaminant concentration: 15 ug/L PCE, 205 ug/L TCE, 363 ug/L DCE, 97 ug/LVC (max levels)

• Contaminated saturated zone thickness requiring treatment: 10 feet

• Estimated groundwater velocity: up to 180 feet/year. Note that groundwater velocity controls theextent to which new contaminant is brought into the treatment zone. This contaminant loadingmust be considered when specifying time release compound dosing requirements.

• Current groundwater geochemistry: oxygen <2 mg/L, nitrate <3 mg/L, potential manganesereduction demand <5 mg/L, potential ferric iron reduction demand <25 mg/L, and potential sulfatereduction demand <120 mg/L. Higher competing electron acceptor-based electron donor demandmay require increased amounts of HRC to achieve remedial goals.

The design specifications and costs provided below represent a preliminary design for an acceleratedbioremediation project. This design may need to be adjusted as detailed design and regulatoryoversight issues are finalized. For instance, the following design variables may need to be adjustedprior to the implementation:

• Treatment areas may need to be increased or decreased depending on the overall site remediationstrategy.

• Exact delivery locations should be selected in the final design process. Injection locations mayneed to be adjusted to take into account site features such as underground utilities and other sitestructures.

Regenesis' Applications engineering staff is available to assist in the selection of an appropriate finaldesign.

J:\Technical Services \HRC\Proposals \HDR\Hatch Co\Hatch Co site OKL0203-205h.doc


Preliminary Design and Cost Information for Full Scale Remediation

It is assumed that the full-scale remediation approach for the site would consist of a combination ofgrid-based application to reduce contaminant levels in the source area and barrier-based application toreduce risk associated with downgradient contaminant migratioa

We recommend applying HRC via two applications: 1) an HRC grid centered around MW-2S to dealwith contaminant levek in the source area, and 2) an HRC-X barrier extending across thedowngradient property boundary to provide a long-term solution to off-site contaminant migration(see attached figure). Although Figure 5 outlines the extent of the source area, none of the soil samplelocations are indicated in the other figures, making it difficult to transpose that source area plume ontothe general site plan. Therefore we indicated the 21,000 ft2 source area as a rectangle around MW-2S.Application details are as follows:

HRC Grid Treatment

Design Feature Specification

Saturated thickness requiring treatment 10 feet

Treatment Area Approximately 21,000 ft2

Delivery Pt. Spacing and Configuration 10 ft-on-center bet. rows, 10 ft-on-center within rows

~ 210 total points

HRC appl rate in Ibs/vertical foot of injection 4 Ibs/foot (40 Ibs/point)

Material requirement 210 pts x 10 feet x 4 Ibs/ft = 8,400 Ibs

Material cost at $5.75/lb* $48,300 plus shipping and applicable sales tax

*Based on the above-proposed HRC application, the total amount of material proposed for this injection is8,400 pounds. If all of the HRC is purchased in the same order, the cost will be $5.75/pound. Therefore,the total cost of 8,400 pounds of HRC is $48,300 plus applicable sales tax and shipping. If less or moreHRC is purchased than the total amount proposed, the cost per pound may be greater or less than the $5.75per pound quoted above. Please see the attached price sheet for HRC volume pricing structure.

HRC-X Barrier Treatment

Design Feature Specification

Saturated thickness requiring treatment 10 feet

Treatment Area 240 foot long barrier

Delivery Pt. Spacing and Configuration 15 ft-on-center within rows

2 rows of 16 points; 32 total points

HRC-X appl rate in Ibs/vertical foot of injection 6.5 Ibs/foot (65 Ibs/point)

Material requirement 32 pts x 10 feet x 6.5 Ibs/ft = 2,080 Ibs

Material cost at $9.50/lb* $19,760 plus shipping and applicable sales tax

*Based on the above-proposed HRC-X application, the total amount of material proposed for this hjectionis 2,080 pounds. HRC-X is shipped in buckets weighing 30 pounds. 2,080 pounds of HRC-X equals 69.3

J:\Technical Services\HRC\Proposals \HDR\Hatch Co\Hatch Co site OKL0203-205h.doc


buckets. Rounding up to 70 buckets yields 2,100 pounds. If all of the material is purchased in the sameorder, the cost will be $9.50/pound. Therefore, the total cost of 2,100 pounds of HRC-X is $19,950 plusapplicable sales tax and shipping. If less or more material is purchased than the total amount proposed, thecost per pound may be greater or less than the $9.50 per pound quoted above. Please see the attached pricesheet for HRC-X volume pricing structure.

The costs provided above apply to HRC-X material costs for one application. The need for re-applications will depend on your plume management strategy, site specific biodegradationperformance, remedial goals for the site, and other technical or regulatory considerations. For barrier-based designs, re-applications maybe necessary every two to three years as long as there is acontinuing need to prevent off-site contaminant migration.

Total Project Cost

The total cost of an accelerated bioremediation project can be estimated as the sum of the followingitems:

• HRC material and shipping costs.

• HRC injection fieldwork costs. Customers are responsible for selecting a local injectionsubcontractor.

• Groundwater monitoring well construction (if necessary to monitor project performance).

• Periodic groundwater sampling and analysis.

• Consultant oversight and reporting. Regenesis data evaluation and technical support are providedfree of charge.

HRC Delivery to Contaminated Zone

Typically, HRC is applied using direct push hydraulic equipment. Drive rods are pushed to the bottomof the contaminated saturated zone and then HRC is injected as the rods are withdrawn. The minimumrecommended rod size is a 0.625-inch inner diameter. For sites where direct push is not feasible,auger-based equipment can be used to deliver HRC. Also, the use of permanent, small diameter re-injection wells may be a more cost-effective approach for sites requiring repeated applications ofHRC. Technical support personnel at Regenesis are available to discuss the suitability of alternateHRC delivery methods.

Costs for HRC injection should be obtained from local subcontractors. If necessary, Regenesis canassist in locating qualified HRC injection subcontractors. Budgetary cost estimates for direct push-based injection range from $1,000 to $2,000 per day. Typically, one to two HRC injection points canbe completed per hour and up to 20 points can be completed per day, depending on soil type, depthsof injection, and subcontractor experience.

HRC should be injected using an appropriate pump capable of processing a material with a viscosityof 20,000 centipoise at flow rates of 3 to 10 gallons per minute at pressures ranging from 200 psig to1,500 psig. Failure to use appropriate equipment could increase field time and result in improper

J:\Technical Services\HRQProposals \HDR\Hatch Co\Hatch Co site OKL0203-205h.doc


application of the HRC. Regenesis can provide a suitable pump for a cost of $150 per day plusshipping.

Recommended Groundwater Monitoring Program for Pilot/Full Scale Treatment

Monitoring of selected wells should be conducted to validate the HRC-based enhancement ofreductive dechlorination processes. Also, an initial or "baseline" round of sampling should beperformed to identify pre-HRC installation groundwater conditions. After delivery of the HRC to thesubsurface, samples can be collected on a monthly or bi-monthly frequency. After the initialbiodegradation and geochemical trends have been identified, the monitoring frequency can bedecreased to a quarterly, semiannual, or annual program.

The monitoring program should employ low flow groundwater sampling techniques and include themeasurement of the following field/chemical parameters:

• all relevant contaminants

• field parameters: dissolved oxygen, ORP, pH, temperature, and ferrous iron (optional fieldmeasurement)

• natural attenuation/inorganic parameters: total and dissolved iron, total and dissolved manganese,nitrate, sulfate, sulfide, and chloride

• HRC-based electron donor: total organic carbon and metabolic acids (lactic, pyruvic, acetic,propionic, and butyric)

• End-product dissolved gases: carbon dioxide, methane, ethane and ethene

A specially qualified laboratory should do the analytical testing for the metabolic acids, otherwisemost laboratorie s can provide testing for the remaining parameters. A typical cost for the abovetesting program is approximately $300 per sample.

Regenesis appreciates the opportunity to provide this information for your project. Please feel free tocontact Mike Sieczkowski, Regenesis' Central District Business Development Manager, at913.894.6605 (e-mail at mike(5),regenesis.conri or me at 949.366.8000 (e-mail atkevin(5),regenesis.com).

Sincerely,

Kevin LapusApplications Engineer

J:\Technical Services\HRC\Proposals \HDR\Hatch Co\Hatch Co site OKL0203-205h.doc

PRICE SHEETTo order call 949-366-8000Fax 949-366-8090

HYDROGEN RELEASECOMPOUND

Effective Date: April 4, 2003

Hydrogen Release Compound (HRC®) offers a passive, low-cost approach to rapid remediation of chlorinatedsolvent impacted sites. HRC is a proprietary, environmentally safe polylactate ester specially formulated for slowrelease of lactic acid upon hydration. When placed within a contaminated aquifer, HRC stimulates a multi-stepprocess resulting in the degradation of chlorinated solvent compounds such as PCE, TCE and their derivatives aswell as other groundwater contaminants.

HRC Pricing*Regenesis offers a volume discount structure for the purchase of HRC as follows:

Quantity (Ibs.)150500

1,5003,000

HRCPrice/lb. (US $)$8.00$7.50$7.00$6.00

Quantity (Ibs.)6,00010,00020,00040,000

HRCPrice/lb. (US $)$5.75$5.50$5.25$5.00

* HRC is shipped in four-and-a-quarter gallon containers weighing approximately 30 pounds. Material Safety Data Sheet is included witheach shipment.

Freight - All freight is FOB San Clemente, CA unless otherwise specified when order is placed.

Minimum Order- 150 Ibs. ($1200.00)

I Bench-Scale Laboratory TestingLaboratory testing of soil and groundwater is available to confirm the ability of HRC to stimulate dechlorination.However, such testing is generally not required. Testing cost is $3,500 per groundwater/soil slurry sample.

Payment Terms - Net 30 days. Accounts outstanding after 30 days will be assessed 1.5% interest per month.Accounts outstanding over 90 days will be re-invoiced at the undiscounted price of $8.00 per pound.

Return Policy-A 15% restocking fee will be charged for all returned product. Return freight must be prepaid.All requests to return product must be pre-approved by Regenesis. Returned product must be in original conditionand no product will be accepted for return after a period of 90 days from time of delivery.

Terms & Conditions - Other terms and conditions are on reverse side.

Order From - REGENESIS 1011 Calle Sombra« San Clemente, CA 92673-6244Tel: 949.366.8000 • Fax: 949.366.8090 • www.regenesis.com • [email protected]

Remittance Address: Department 8873Los Angeles, CA 90084-8873

REGENESIS1011 Calle Sombra* San Clemente, CA 92673-6244

Tel: 949.366.8000 • Fax- 949.366.8090 • www.regenesis.com • [email protected]

Registered Trademark of REGENESIS Bioremediation Products

HYDROGEN RELEASE -COMPOUND

PRICE SHEET EfFective Date: April 4'2003

To order call 949-366-8000Fax 949-366-8090

[extended release formula]

HRC-X™ - for the Effective Treatment of Chlorinated Compounds and Residual DNAPL

HRC-X offers a passive, low-cost and effective approach to the remediation of chlorinated solvent impacted sitesincluding high concentration residual DNAPL sites. HRC-X is a proprietary, environmentally safe, polylactateester specially formulated for the slow release of lactic acid upon hydration. When placed within a contaminatedaquifer, HRC-X stimulates a multi-step, biological process resulting in the degradation of chlorinated solventcompounds such as PCE, TCE and their derivatives as well as other groundwater contaminants. The use ofHRCresults in the cost-effective restoration of contaminated sites.

Quantity (Ibs.)< 3,0003,0006,00010,00020,00040,000

HRC-X Price/lb. (US $)9.509.008.508.007.757.50

* HRC is shipped in four-and-a-quarter gallon containers weighing approximately 30 pounds. Material Safety Data Sheet is included witheach shipment.

Freight - All freight is FOB San Clemente, CA unless otherwise specified when order is placed.

Minimum Order - 1 50 Ibs. ($ 1 ,425 . 00)

Bench-Scale Laboratory TestingLaboratory testing of soil and groundwater is available to confirm the ability of HRC-X to stimulatedechlorination. However, such testing is generally not required. Testing cost is $3,500 per groundwater/soil slurrysample.

Payment Terms - Net 30 days. Accounts outstanding after 30 days will be assessed 1 .5% interest per month.Accounts outstanding over 90 days will be re- invoiced at the undiscounted price of $8.00 per pound.

Return Policy -A 15% restocking fee will be charged for all returned product. Return freight must be prepaid.All requests to return product must be pre-approved by Regenesis. Returned product must be in original conditionand no product will be accepted for return after a period of 90 days from time of delivery.

Terms & Conditions - Other terms and conditions are on reverse side.

Remittance Address: Department 8873, Los Angeles, CA 90084-8873

Order From - REGENESIS

REGENESIS101 1 Calle Sombra* San Clemente, CA 92673-6244

Tel: 949.366.8000 • Fax: 949.366.8090 • www.regenesis.com • [email protected]

REGENESISTERMS AND CONDITIONS

1. CASUALTY AND AVAILABILITY OF RAW MATERIALS. REGENESIS Bioremediation Products ("Seller") shall not beliable for delays in delivery or failure to manufacture or deliver due to causes beyond its reasonable control, including but not limited to actsof God, acts of buyer, acts of military or civil authorities, fires, strikes, flood, epidemic, war, riot, delays in transportation or car shortages, orinability to obtain necessary labor, materials, components or services through seller's usual and regular sources at usual and regular prices. Inany such event seller may, without notice to buyer, at any time and from time to time, postpone the delivery dates under this contract or makepartial delivery or cancel all or any portion of this and any other contract with buyer without further liability to buyer. Cancellation of anypart of this order shall not affect seller's right to payment for any product delivered hereunder.

2. LIMITED WARRANTY. Seller warrants that the product sold hereunder is made with HRC-X as specified on face of invoice. Sellermakes no other warranty of any kind respecting the product, and expressly DISCLAIMS ALL OTHER WARRANTIES OF WHATEVERKIND RESPECTING THE PRODUCT, INCLUDING ALL WARRANTIES OF MERCHANTABILITY AND FITNESS FORPARTICULAR PURPOSE. BUYER'S SOLE REMEDY FOR BREACH OF THIS LIMITED WARRANTY SHALL BE REFUND OF THEPURCHASE PRICE, PROVIDED THAT ANY UNUSED PORTION OF THE PRODUCT IS PROMPTLY RETURNED TO SELLER.UNDER NO CIRCUMSTANCES WILL SELLER BE LIABLE FOR ANY CONSEQUENTIAL OR OTHER DAMAGES.

3. DISCLAIMER. Seller disclaims to the full extent permitted by law all warranties, expressed or implied, including any impliedwarranty of merchantability, fitness for any particular purpose or against infringement, to any person other than buyer. Where warranties to aperson other than buyer may not be disclaimed under law, seller extends to such a person the same warranty seller makes to buyer or lesseeas set forth herein, subject to all disclaimers, exclusions and limitations of warranties, all limitations of liability and all other provisions setforth in the Terms and Conditions herein. Buyer agrees to transmit a copy of the Terms and Conditions set forth herein to any and allpersons to whom buyer sells, or otherwise furnishes the products and/or services provided buyer by seller and buyer agrees to indemnifyseller for any liability, loss, costs and attorneys' fees which seller may incur by reason, in whole or in part, of failure by buyer to transmit theTerms and Conditions as provided herein.

4. LIMITATION OF SELLER'S LIABILITY AND LIMITATION OF BUYER'S REMEDY. Seller's liability on any claimof any kind, including negligence, for any loss or damage arising out of, connected with, or resulting from the manufacture, sale, delivery,

:sale, repair or use of any goods or services covered by or furnished hereunder, shall in no case exceed the lesser of the cost of repairing orreplacing goods failing to conform to the forgoing warranty or the price of the goods or services or part thereof which gives rise to the claim.IN NO EVENT SHALL SELLER BE LIABLE FOR SPECIAL INCIDENTAL OR CONSEQUENTIAL DAMAGES, OR FOR DAMAGESIN THE NATURE OF PENALTIES.

5. INDEMNIFICATION. Buyer agrees to defend and indemnify seller of and from any and all claims or liabilities asserted against sellerin connection with the manufacture, sale, delivery, resale or repair or use of any goods covered by or furnished hereunder arising in whole orin part out of or by reason of the failure of buyer, its agents, servants, employees or customers to follow instructions, warnings orrecommendations furnished by seller in connection with such goods, by reason of the failure of buyer, its agents, servants, employees orcustomers to comply with all federal, state and local laws applicable to such goods, or the use thereof, including the Occupational Safety andHealth Act of 1970, or by reason of the negligence of buyer, its agents, servants, employees or customers.

6. EXPENSES OF ENFORCEMENT. In the event Seller undertakes any action to collect amounts due from Buyer, or otherwiseenforce its rights hereunder, Buyer agrees to pay and reimburse Seller for all such expenses, including, without limitation, all attorneys andcollection fees.

7. TAXES. Liability for all taxes and import or export duties, imposed by any city, state, federal or other governmental authority, shall beassumed and paid by buyer. Buyer further agrees to defend and indemnify seller against any and all liabilities for such taxes or duties andlegal fees or costs incurred by seller in connection therewith.

8. ASSISTANCE AND ADVICE. Upon request, seller in its discretion will furnish as an accommodation to buyer such technicaladvice or assistance as is available in reference to the goods. Seller assumes no obligation or liability for the advice or assistance given orresults obtained, all such advice or assistance being given and accepted at buyer's risk.

9. ENTIRE AGREEMENT. This agreement constitutes the entire contract between buyer and seller relating to the goods or servicesidentified herein. No modifications hereof shall be binding upon the seller unless in writing and signed by seller's duly authorizedrepresentative, and no modification shall be effected by seller's acknowledgment or acceptance of buyer's purchase order forms containingdifferent provisions Trade usage shall neither be applicable nor relevant to this agreement, nor be used in any manner whatsoever to explain,gualify or supplement any of the provisions hereof. No waiver by either party of default shall be deemed a waiver of any subsequent default.

Appendix C-3Carbtrol Corporation


CARBTROL'C O R P O R A T I O N

June 17, 2003

Ms. Allison McCorroickHDRRe: Sail Lake City

BUDGETARY QUOTATION

OTY DESCRTPTION DINT PRICE EXT. PRICE

Alternative One: Air Stripping:

1 Model MSD-2-100 Multi-Stage Diffuser $5,775.00Includes 2HP, 10, TEFC blower with airflow switch and hi level switch.

1 Model MSDPSSLP-20 pump sump system $1,250.00

1 NEMA 4 control panel $6,380.00Includes main power disconnect, magnetic motorstarters with thermal overload relays for each motor,alarm indication lights, (7)8&W relays (one for eachwell pump), hand/off/auto switch for each motor,locking dead front. Mounted on MSD blower skid. ;'

Alternative one total: $13,405.00

Alternative Two: Activated carbon:

2 L-l carbon canister with 200 Ibs. virgin carbon $518.00 $1,036.00

1 PFB-10 prefilter $725.00

1 PK-10 piping kit $350.00

1 Model PSSLP-20 pump sump ; $1,650.00

1 NEMA 4 control panel $5,800.00Includes main power disconnect, magnetic motorstarter with thermal overload relay for transfer pumpmotor, alarm indication lights, (7)B&W relays (one for eachwell pump), hand/off/auto switch, locking dead front.Supplied loose

Alternative two total: $9,561.00

• Field piping and wiring by others.• Freight and handling not included.• Availability: 4-6 weeks

TERMS: 30% down, 65% before shipment. Balance 30 days.FOB: Bridgeport, CTSHIPMENT: Shipping dates are based on current backlog and subject 10 confirmation at time of order.SALESPERSON: JMQUOTATION VALID FOR SIXTY DAYSJM

6/z 'd o o s o ' ° N NOUVHOJHOD loravo w v i i ' O i

6/17/03 DIFFUSED AIR STRIPPER REMOVAL ESTIMATE 3:41 PMCopyright© 1994-1996 CARBTROL® Corporation

PROJECT: Salt Lake CityFLOW IN GPM: 8 # OF STAGES REQUESTED: Z

TEMP INT: 55 DESIGN CFM PER CELL: TOOSTRIPPER TYPE: Multi-Stage Diffuser

MSD-2-100PERFORMANCE:

ACTUAL AIR DISCHARGECONTAMINANT INFLUENTfnob) EFFLLJENTrppbl K FACTOR #/DAY

Trichloroethylene 1000 6.73 3.580 0.10 0.99Tetrachtoroethylene 15 0.14 3.032 0.00 0.011,1-Dichloroelhylene 400 9.08 1.804 0.04 0.52Vinyl Chloride 100 0.04 15.669 0.01 0.21

TOTALS 1515 15.99 0.14 1.73

NOTE: Air strippbr performance is based on the data provided. Presence of other compounds, especially surfactants that cause foaming,may significantly affect performance of the stripper.

CARBTROUMULTI-STAGE

DIFFUSED AIR STRIPPER- RESISTANT TO IRON FOULING -

COMPONENTS

• Aeration compartments - PVC Construction with UVprotection.

• Blowers - centrifugal type, direct drive, anti-spark.

• Motors and starters - TEFC or Explosion Proof.

• Two skids - one for blower, one for aerationcompartment.

SPECIFICATIONS

MODEL/STAGES

MSD-2

MSD-4

MSD-6

MSD-8

MSD-12

CFM'

100/200

200/400

300/600

400/600

600/1200

hLE

2/2

2/5

3/7.5

5/7.5

7.5/10

APPROXIMATEFOOTPRINT

4'x3-ST

4'x5'-4'

4'xff-n"

4'x8'-6"

4'x\Z:-4"

* Each aeration compartment is designed for either 50 CFM(normal operation) or 100 CFM (high air flow operation).

FEATURES

•, Easy to clean -No trays or packing to plug. Quickremovable cleanout cover allows easy

: access to aeration compartment.

• High efficiency - removals up to 99.99%.

• 'Multiple stages to handle varying treatmentrequirements.

• Standard design up to 50 gpm.

• Very low profile.

INLET PIPE

OUTLET PIPE

FOUR STAGESTRIPPER

CARBTROLC O R P O R A T I O N

6/i 'd 0 0 5 0 ' O N

© Copyright 1991 Caitrtrol Corporation -1/6/00

955 Connecticut Ave, Suite 5202Bridgeport, CT 06607

AT-75OT1

800-242-1150 Fax: 203-337-4353www.carbtroLcom [email protected]

mi '8

po

r-o

POWER SUPPLY

CONTROLPANEL "

(SHIPPED -" ~ 1LOOSE)

I TO

1 ATM

SLIDE 1 IGATE j HIGH

- - | -AIR - LEVEL*\ 1 FLOW PUMP CONTROL

!! \ !/T rh \it \PQ'e>P '"*i~-=jg| ^M — u. • fc 1 ^

ii i JLL ™ J™ " ^

C-

cc.

f>fc^crc

CHECK £VALVE - - . ^

\ =\ »¥ TREATEDIj EFFLUENT

r\-| II r- ' ' ' 1 ' / \ '

ii BALL' \j| VALVE | \

!! MULTI-STAGE DIFFUSER MSD PUMP GATEII AIRSTRJPPER SUMP VALVEj« MSD-2-100 SYSTEM,| LP-20

.1f-i,J ^.___^

\[ |l fÂDRTDOl ® 9S5 CONNECTICUT AVENUE -c

>--J WrÎlD 1 nVXL. BRIDGEPORT CONN. 06607 -(TVP OF 7 WELLS) C O R P O R A T I O N (203)337-4340 £

or*Ai c

NOTES: DATE 7-M3

BY CJRRAI T 1 AKF CITY .,..,-

REV 1

EQUIPMENT. ELECTRICAL A PIPING BY OTHERS GROUNDWATER TREATMENT SYSTEM £PN

EQUIPMENT &PIPI/NG BY CARBTROL FLOWSHEET | S | DWG CR 070 8 03/0

CO

CO

CARBTROL

OL-.Oe:CD

oe:E—CQ

Why CARBTROL'S Diffused Air Stripper Is The Best!

Very low profile enables gravityflow from upstream processes.No transfer pumps required.

Easily lined with activatedcaifaon off gas treatment.

Quick open access covers allowcleaning by one person in lessthan 30 minutes.

Rugged duty polymerconstruction eliminatescorrosion. EFFLUENT

Height -3'-0"

Modular design and flow throughair header peimit addition ofstripping cells.

Air spargers are easily removed byhand and lifted out for cleaningor replacement.

TYPICAL FOUR STAGEDIFFUSED AIR STRIPPER

Integrated control center monitorskey performance parameters.

Low pressure centrifugal fanprovides low air temperaturesand reliable operation.

All mechanical componentslocated on a separate powerskid for ease of Installation andservice.

Staged multi-cell design providesvoc removal efficiency equal totray stripper or tower.

OJ

CO

CARBTROL*CORPORATION

61 Riverside Avenue, Westport, CT 06880 • 1-800-242-1150* (203) 226-5642

© Copyright 1996 Carbtrol Corporation - 7/17/96 AT- 75Qtt6

TERMS i^CONDTITQNS

1. PROPOSAL. CARBTRQIA's purpose \t to Cumuli the Customer me equipment as covered by Out proposal and ipcdficatlnat ct the prices cured herem.

Prices we fine fa shipment within, all (6) monift* of the ado date if the orter is placed within GO days.

For sUpmeau made jnmjBu tiz (Q montlK from the del* of the order, pricing will be that in effect at lime of shipmut. OF shipment li delayed for reasonsunder control of CARBTROL. duo the price jball reoatn tan)

All the infonnab'm in die proposal is confidential Md lux been prepared for Customer we solely In eensidenag the purchase of the equipment described.Transmisnon of ill or my pin of toil information to others by Cutumer for other purpMet i> Uniutbarized without CARBTROL's written content.

2- TERMS OF PAYMENT- Net payment »fthin 90 o»jr« from invoice date subject to credit approval by CARBTROL. CARBTROL resorts ma right u> invoiceOA finished goods if conamtr holds delivery beyond scheduled shipping dale. CARBTROL reserves the right to Invoice on partial slnpmcnli, AD overdueaznounu of the porcbase price ihil] bar intaren atthe rate of 1 1/2* per month. If payment remans delinquent ID excen of 60 days, CARBTROL reserves thenght B> tailae m fniltjieriiliiru Collection Agent to stone payment, li such case. Purchaser shall pay the balance due. plui 25% added for toe Collection fee.

3. PAYMENT BY CREDIT CARD. Due ID the addjiioail costs Incurred 10 process credit card paymni:, a 4* Processing Fee is added to all orden that are paidby credit card.

4. SHIPMENT. F.OB, plant as per CARBTROL'J proposal mlable for domeitlc ihlpomt. ualeu oUierwMe ipaified. Shipping date given taemn BC•ppraxioale only and Hbject to eonfirnmUonmt time ol order. r\ufliumi e. djlat are eanpiBed from tune of receipt at CAkblVOL Office, «U OtaUt penamagto *• order •Ua *e euoBlW sa iu proper «BKI«JOB. ;•

-S. WARRANTY. All taapmaA Buofietvred by CABBIROL a wennudto be free from defeat in maenal and vorkmtniUp {or o period of IS mantbi Annlh> OVA of BbpaeBt or 12 tooute Erom ibe dee of Men up. whichever cam« Cm. CARBTROL vill repair or rcplaee any pan or pans during the warrsaty penodfr«e of cbargB. F.OB, factory, pjmliteil DOT niamlnmloM «bow« tbe equipineai to be truly defective whoa uted for the purpose mlorfcd. The obligaiuin ofCARBTROL a Imaud aoldy to rep«r not to exceed tht con of the deleaive eouipmcni considered on a unit Bwis, or replacement of raid arannaau. TinsobliflKtea dull oe eanttioaed men rronnx -rinen notice bone given to CARBTROL. CARBTRQL MAKES NO WARRANTY AS TO FITNESS OF ITSPRODUCTS FOR SPECIFIC APHjCAXfONS BY THE BUYER OR AS TO PERIOD OP SERVICE UNLESS CARBTROL SPECIFICALLY AGREESOTHERWISE IN WRITING AFTER THE PROPOSED USAGE HAS BEEN MADE KNOWN.' The foregoing warranty if executive and in hen of all othervotrftftUM ayirnmol or iBplied, induaint bin sot looted to my voranly of merchanubUriy or of rmoH for a particular purpose. Commcdftiei notmanttfaetured by CARBTROL <re manmed or guaranuad to tbe extent aad in the manner '(hey may be woraniad or guaranteed to CARBTROL by themanufacturer (hereof, and 10 the ratal roch fanny or gnamnr may reasonably be enforced without litigation by CARBTROL

£. LIMITATION OF UABUJTY. In no eveai, a a mult of breach of contract wmmy or negligence, shall CARBTROL be liable for special or eencequenutldamans Including but not limned to loai of profits or revenues. Iocs of any equipment, con of capital, coat of cubtljtule equipment, facilities or unrieet,de«attme coo or chin* of ewdnten of the Customer for nicb. damages. Further, CARBTROL »fll not be table for any delay it the performance of cottncuan4 erdera, or iB (be impmeni am delivery of foods, or for toy damage Buffered by me Bakle for any delay in fbc performance of emmets oaO orders, or in thethipnaot and delivery of apedl. or for any damage suffered by the Customer by reason of delay, when such delay ii. directly or indlrecOy, caused by or in anymanor tries from fn, floods, aoddant, riou, war, Ocvermneni una&rencc. piorines, embargoei. strikei, shortage of labor, foal, material! or supplies.madeqaate tnnqmrojdon facaiun or any other caiwe or eauiea vhe(her or not similar in nanrt to any of Uieie berembeforc specified beyond CARBTROL'scontrol.

7. SERVICE. Where service in the nature of lonaJtaiioB, demonstreucm or rcpnr of any equipment beyond toil specifically included in the quoted price.CARBTROL will reader such services at Its normal chargei plot overtuno and living and traveling eipenies for a mechanic and/or engineer.

g. PERFORMANCE Wh« pertonnaaee ef CARBTROL;. equipment is baaed on data furnished by Customer, it should be understood (bat CARBTROL'jpAtcnisnicefifuresarecftimattd only, based m «he reliable engineering practice. The actual performance obuwed by Cunomcr may be influenced by anychanges in enndMoos prevtjtng it Cudomer's plant 01 foe.

9. PATENTS. CARBTROL assumes no responsibility for any claims that *fld eouipmcat infringes on rignis or paieou of others.

10. CLAIMS. Claims for loas or damage in mush are Ifie renensibiUly of Ibe coongncc: however, CARBTROL wfll lend auatance. Any claims for shonigesBOI covered by (he freight tamer, must be made wunin ten (10) dayi from taie of delivery. In order to receive coosideniion.

11. STORAGE FEES. A storage fee will be charged for finished goods if Customer holds delivery beyond scheduled shipping date. Afur a seven (7) day graceperiod. Customer wiD.be charged a monttly flung* rate of S2DO per S10.000 of purchaie prlcel

12- FRSQHT HANDL1NO CHARGE • A 33* ii-ndim. charge is added to all treiahi bills mat *e pay for our avuman The handing charge oove»artmnrisrrauon cosu Barndsiefl wjih nsyiag the freight bill at «cll m me value of money regarding Ibe tune of payment of the fraigpi bul versus customer'spayment of oar invoice. ICC Federal Regulations require us to poy freight billi within 15 days. The handhnc charge does not apply to outboundttopmenu tint are sent "Frcighl CoUeeT.

13. CANCELLATION. Any orden placed for equipment and comnoojtlc* « orTered in this proposal shall not be subject to cnncellaiioa except withCARBTROL's onnaeM, and (ben only upon (be following conditions:

Standard Equrpmaal - (DeQaeO as catalogued eoutpmeni ordinuily canisd In stock.) Whet OnceUalioti it accented, CARBTROL reserves thr. right to make acntocUauon charfe up to 25% of the purcban pnce.

Special Equmneai - (Defiied as einipmeav noflUfaeiured for special requirement* and not slocked as iknuard product.) Cancellation will be accepted uponpayment, of a percentage of (ha total apeda! emilpmejt price aqua) to the percentage of the total wort completed.

14. TAXES Our propose] dees not include Federal. State or Local Salei, Privilege, Use or other BUCJ of any kUd applicable to the sale of the equipmentinvolved. Unless otherwise specified, these noes shall be paid by the Customer or. in Hiu (hereof, Ibe Customer ihall provide CARBTROL with a taxexemption certificate acceptable to die proper taxing •utboniy.

15. OTHER. This narecmem shall be construed m accordance with Wit laws of the State of Connecucut. The* Terms and Conditions an the only terns andcondition] that will be binding upon the ponies unless additional terms are set forth in writing and agreed to between the panics in writing.

T/C - d/2/01

6/6 'd 0050 'ON N O U V H O d H O O 10MV3 W V B I ' O I

Appendix C-4Hydroxyl Systems, Inc.

W.S. Hatch Co HDR Engineering, Inc.Focused Feasibi lity Study Final Report July 2004

Budgetary Proposal

For

HDR,Inc.303 E. 17th Avenue, Suite 300

Denver, CO 80203Ms. Allison McCormick.

Tel: (303) 764-1581Fax:(303)860-7139

[email protected]

UV Oxidation System for Treatment ofGroundwater Contaminated with VOCs

Project #4598

July 4, 2003

Prepared byHYDROXYL SYSTEMS INC.

Tel: (250) 655-3348 Fax: (250) 655-3349

Budgetary Proposal HDR, Inc..Groundwater Treatment System July 4,2003

Table of Contents

Technical Proposal 1

1.0 Introduction 12.0 Design Treatment System Feed Characteristics 13.0 Design Basis 24.0 Technology Description 25.0 Process Description. 36.0 Operating Consumables 57.0 Scope of Battery Limit Process Engineering 68.0 Scope of Supply 79,0 Operating and Maintenance requirements 8

Commercial Proposal 9

1.0 Prices and Terms 92.0 To be provided by the Purchaser 93.0 Proposed Schedule 104.0 Protection of HYDROXYL Technology 10

Budgetary ProposalGroundwater Treatment System

HDR, Inc..July 4, 2003

Technical Proposal

1.0 Introduction

HDR, Inc. is evaluating technologies for treating a groundwater contaminated withvarious VOCs including chlorinated VOCs (PCE, TCE, DCE, and Vinyl Chloride).Based on our experience with similar groundwaters, HYDROXYL SYSTEMS is proposing theUV-Hydrogen Peroxide (HYDROXYL-UVP) process for this groundwater. The proposedUVP system has the following advantages when compared to carbon adsorption systems:

•«• The UV oxidation process destroys the VOCs rather than transferring them toanother medium.

•I* Vinyl chloride may polymerize in the carbon column, resulting in high carbonconsumption, whereas in the UV oxidation system, it is easily destroyed.

•J* Operator and maintenance free operation.

2.0 Design Treatment System Feed Characteristics

The characteristics of the groundwater and effluent limits are shown in the table below.

Groundwater Quality and Design DataParameter

Flow

Flow

Temperature

pHAlkalinity

Chlorides

TDSConductivity

HardnessNitrates

Ferrous Ion

TSSSulfates

Sulfides

Oxidation Reduction Potential (ORP)

TOCEstimated COD

VOCs

bitxTetrachloroethene (PCE)

Trichloroethene (TCE)

Dichloroethene (DCE)

Vinyl Chloride

Dichloroethane (DCA)

Units

GPDGPM

("C)

mg/Lmg/Lmg/L

micromhosmg/Lmg/Lmg/L

mg/Lmg/Lmg/LmV

mg/Lmg/L

ug/L

ug/Lug/Lug/L

ug/Lug/L

After MetalsRemoval and Air

Stripper

11,520

8

Ambient

6-7

400

250

MA

NA

MA

1.5

0

NA

120

0

250

2.0

10

10

15

1000

400

100

10

EffluentRequirement

5

5

5

5

5

5

Orders ofReduction

030

0.48

230

1.90

1 30

030

NA: Not Applicable. Provision of these data will enable a more precise treatment system specification.

HYDROXYL SYSTEMS INC. Page I Project 1-4598


3.0 Design Basis

This proposal is based on design data listed in the table in section 2.0 and our experiencewith similar groundwaters. The effluent limitations for the groundwater have not beenfinalized, and the values listed in the table are estimated. The primary compound thatneeds to be treated is TCE. When TCE effluent limit is reached, other VOCs will bereduced to below their effluent limits.

The design of an UVP is based on an electrical energy per order (EE/O) of 5 KWh/1000-gallons/order of TCE reduction. One order of reduction is 90% reduction in TCEconcentration. The estimated UV power requirement for the UVP process is 6 KW,requiring one UV reactor. The UV lamp inside the reactor is rated for 20 KW butoptimally operated at 16 KW. The UV lamp can also operated at 12 KW for thisapplication? It is estimated that a peroxide dose of 10 mg/1 is necessary.

The above design is based on estimated COD concentration 10 mg/L. The proposeddesign offers substantial operational flexibility. It can be used for influent concentrationsmore than double the average concentration of TCE, or the flow can be increasedsubstantially. A design test with the actual groundwater is necessary before a firm priceproposal with a performance guarantee can be provided. A design test proposal can beprepared for this purpose if requested.

4.0 Technology Description

The HYDROXYL-UVP process is an Advanced Oxidation Technology (AOT) that involvesthe use of high intensity UV light and hydrogen peroxide to generate hydroxyl radicals, ahighly reactive radical species. Hydrogen peroxide is mixed with the contaminated waterand is pumped through the UV reactor(s). The UV light photolyzes the hydrogenperoxide producing hydroxyl radicals, which within a few seconds, will oxidize theWater-Soluble Organics (WSO) to benign byproducts and the effluent is disinfected.

The UVP process is based on UV photolysis of hydrogen peroxide in solution. Hydrogenperoxide absorbs weakly in the UV region and the absorption increases with decreasingwavelength. The molar extinction coefficient (ex) is 18 M"1 cm"1 at 254 and 190 M1 cm"1

at 190 nm. The primary process for absorption of light below 350 nm is dissociation toproduce two hydroxyl radicals:

H2O2 + hv -> 2 »OH

The quantum yield for production of »OH (hydroxyl radicals) is 1.0.

To some degree, there is a tradeoff between the intensity of UV light applied and theconcentration of hydrogen peroxide. In general, higher concentrations of peroxide willabsorb greater proportions of the applied UV light, so that the UV power required toperform the same treatment effect will decrease. However, peroxide competes with

HYDROXYL SYSTEMS INC. page 2 Project 1-4598


water-soluble organics for hydroxyl radicals and high peroxide concentrations can reducetreatment efficiency. For each application there will be an optimum combination of UVdose and peroxide dose. Typically, the peroxide concentration will need to be sufficientto absorb 35 to 40% of the applied UV light.

5.0 Process Description

The groundwater will be homogenized and equalized in customer supplied equipment,and pumped (if necessary) by a customer supplied pump to the HYDROXYL-UVP treatmentsystem.

A hydrogen peroxide (50%) solution will be introduced to the groundwater. Theperoxide flow will be adjusted in proportion to the flow to meet dosage targets entered inthe PLC. The PHOTOSTACK lamp, with its optimized UV spectrum, photolyzes thesolution to generate hydroxyl radicals. The hydroxyl radicals quickly destroy the targetcontaminants. Periodically an electrically driven wiper automatically will clean anydeposits from the outside of the quartz tube.

The treatment systems described above will be controlled by the PLC equipped with aDigital Operator Interface. The PLC .will control the PhotoStack UV reactors and theperoxide feed flow. From the treatment system the treated water will flow to thedischarge point by gravity.

Instrumentation and controls include a flow meter, pressure gauge, temperature indicator,wiper limit switch, and a temperature transmitter and alarm. The PhotoStack powersupply includes amperage meters and alarms, temperature alarms, and a timer. Digitaloutput devices for all key process variables and a Mitsubishi FX2N series programmablelogic controller are also provided.

The lamp provided is specifically designed to provide the optimum wavelength forhydrogen peroxide activation. The power can be adjusted to 60%, 80% and 100% ofeach lamp's 20 KW rating. This feature allows the customer to operate at the minimumpower cost to achieve the required performance and also run trials at any power setting todetermine the contaminant removal efficiency at any setting. , Operating at lower powerlevels may also extend lamp life.

The treatment system will be installed on a skid for easy transportation and maintenance.The skid can be expanded by stacking additional UV reactors on the skid (maximum fivereactors per skid). Thus, the treatment system can be easily expanded for increased flowor concentrations. Hydrogen peroxide dosage systems will also be installed on the skidThe following simplified schematics and pictures illustrate the skid-mounted UVtreatment systems.

HYDROXYL SYSTEMS INC. Page 3 Project 1-4598



Provided byCustomer

Groundwater

InfluentPump

HYDROXYL PHOTO STACKStainless Steel UV-Reactor (16 KW)

HydrogenPeroxide

Figure 1: HYDROXYL-UVP Flow Diagram

Discharge

Figure 2: Typical HYDROXYL - UV System (Back View)




Figure 3: Typical HYDROXYL - UV System (Front View)

6.0 Operating Consumables

The following consumables and utilities are required for operation of the groundwatertreatment system. Usage rates can be lower for lower flows and concentrations. Basedon average flow conditions, estimated usages are stated below.

Consumables and* Utility Requirements

ConsumableHydrogen peroxide @ 50%, Ib

Annual Annual Costs

UV Lamps

^•KLamp at 12 KWEnergy (KWh)

288 105,000 $5,250

HYDROXYL SYSTEMS INC. PageS Project 1-4598


7.0 Scope of Battery Limit Process Engineering

The following scope of engineering is included:

>• Mass and energy balance sheetOur scope includes a mass and energy balance sheet including expected averageoperating conditions, and maximum/minimum (where applicable) for flow rate,composition, pressure, temperature, and other properties when needed for eachprocess stream.

> Piping and Instrument DiagramThe diagram will include: items of equipment numbered according to theequipment list, process piping required including diameter and material code,requirements for tracing and insulation, all valves, strainers, vents, drains andsample points, all measuring and control instruments, analyzers and indication ofinterlocks.

> Functional and logic descriptionThe scope includes detailed description of the process steps, function of thevarious lines, instrumentation, valves, and tanks. Description of the logic for thecontrol system including grouping of controllers, alarm setting list, data reports,and inside battery limits logic.

> Instrument specifications and operating manuals

> Material and welding certifications can be provided, if requested.

HYDROXYL SYSTEMS INC. page 6 Project 1-4598



8.0 Scope of Supply

The following equipment and instrumentation are included in the scope of supply of thisproposal:

HYDROXYL-UVP Scope of Supply

Quantity11111

11111

11111

311

Description316 SS Medium Pressure UV Reactors20 kW Medium Pressure UV LampQuartz Sleeve housing for UV lampElectronic sleeve wiper mechanisms with limit switches and alarmsElectrical/Control Panel - built to UL standards, including:

• NEMA 4 enclosure• 1 x Master Control Panel with PLC control- system with the

following UV system alarms:•S Power supplies High Temperature AlarmS Reactor High Temperature transmitters and AlarmsS Lamp FailureS Cabinet Door OpenS Quartz Wiper FailureS Reactor Leak Alarm

UL wired Cabinet with Power SuppliesPower Distribution Cabinet with UL componentsSS mounted static mixer70 gallon Hydrogen Peroxide storage tank, HOPE, double walledPeristaltic metering pump with 4-20 mA, silicone tubing, splash guard,spill tray and return lineControl Panel with PLCDigital Operator Interface460 V Distribution PanelSkid for housing UV reactorsFlow meterOther associated instruments and accessoriesO&M ManualsEngineering, Pre- Assembly and Testing at HYDROXYL SVSTEMSSet of record (as- built) drawings

In addition to the above equipment, the following services are also included in our scope:

? Pre-assembly and testing at HYDROXYL facilities? Three sets of all engineering drawings and documents? Three sets of O&M manuals

HYDROXYL SYSTEMS INC. Page? Project 1-4598


9.0 Operating and Maintenance requirements

Three copies of the operating and maintenance manual, detailed equipment specificationsand spare parts list will be provided prior to delivery of the system.

The following operating and maintenance attention is anticipated:

Operator 2 hours/weekMaintenance & instrumentation service Included above

Typical items to be checked and replaced:

> Periodic replacement of lamps (frequency depends on power selection of UVreactors)

~ > Periodic replacement of wiper mechanisms> Inspection of quartz sleeves (usually performed when replacing lamps)> Verify peroxide injection pump calibration> Verify level of peroxide storage tank and top up if necessary

HYDROXYL SYSTEMS INC. Pages Project 1-4598



Commercial Proposal

1.0 Prices and Terms

HYDROXYL is providing this proposal for the treatment equipment on a budgetarybasis (subject to design confirmation with actual groundwater). All prices quotedin this proposal are in US$. The budgetary cost estimates for the proposedtreatment system are provided below:

1.11.21.31.41.5

ItemTreatment system as described in this proposalOn- site commissioning and training assistanceShipping ChargesSales TaxesOther TaxesTotal Costs (before taxes)

US$$88,900

AdditionalAdditionalAdditionalAdditional

$88,900

This proposal is provided with the following terms and conditions.

• Validity: This proposal is for budgeting purposes and not suitable forpurchase orders. The equipment sizing is based on data provided by thecustomer and subject to confirmation by a design test of the groundwater.

• FOB Sidney, BC, Canada. The customer is responsible for shipping charges.• Payment Terms

40% with purchase order25 % with approval of drawings25% before shipment of treatment system10% within 30 days after startup

2.0 To be provided by the Purchaser

S Indoor or weather protected installationS Source of Hydrogen PeroxideS Equalization tank and influent pumping system with flow controlS 460 VAC/30/60 Hz electrical power - connection at Power Distribution CabinetS Plumbing (includes inlet, outlet) and service (power and telephone if required)

connections to designated and provided connectors in the HYDROXYL skidS Unloading of HYDROXYL skid and installation as recommended by HYDROXYLS Compliance with local regulations for installation, startup, and operationsS All regulatory permitting requirementsS Other site-specific factors



3.0 Proposed Schedule

We will provide the various deliverables with the following proposed schedule:

Design Drawings 4 weeks after purchase orderTreatment System Fabrication Completion 10 weeks after approval of drawingsShipping 2 weeks after fabrication completionStartup 2 weeks after shipping

4.0 Protection of HYDROXYL Technology

Several components of the system and the overall system design are proprietary and shallnot be duplicated or copied by the purchaser or disclosed to third parties other than thePurchaser's consulting engineer or other service providers. If the Purchaser changes oradds to HYDROXYL'S wastewater treatment system, for example by adding equipment,controls, changes in procedures, purchase of media or components from others, orchanges it in any other way or if technology or know how of a third party is used, theadditions or changes shall be deemed part of HYDROXYL'S technology and shall not beregarded as separate or independent of the technology. Any such equipment orcomponent added within HYDROXYL process or building module shall be not be removedor altered in the event that the system is returned to the seller.

HYDROXYL SYSTEMS INC. Pageio . Project M598

Appendix C-5ARS Technologies, Inc.

WS Hatch Co. HDR Engineenng, IncFocused Feasibility Study Final Report July 2004

GROUNDWATER REMEDIATION USING FEROXFOR SOURCE AREA TREATMENT

HDR EngineeringHATCHO Site

Woods Cross, Utah

Submitted by:

ARS Technologies, Inc.114 North Ward St

New Brunswick, NJ 08901

SM

July 11, 2003

Table of Contents

1.0 INTRODUCTION AND BACKGROUND 1

2.0 TECHNOLOGY BACKGROUND AND GENERAL TREATMENT APPROACH 2

2.1 Technology Background 2

2.2 General Treatment Approach 3

3.0 SCOPE OF WORK 5

4.0 ESTIMATED PROJECT COST 9

5.0 PROJECT SCHEDULE 11

I ARS Technologies, Inc.

Source Area Treatment Using FeroxSM

HDR Engineering Site UtahJuly 11, 2003

1.0 INTRODUCTION AND BACKGROUND

ARS Technologies, Inc (ARS) is pleased to present to HDR Engineering (HDR) this proposal forthe installation of an in situ groundwater remediation system using our patented Ferox5 processat your clients Source Area in Woods Cross, Utah (the Site). The FeroxSM process involves theinjection of highly reactive Zero-Valent Iron (ZVI) powder into the saturated zone for reductivedechlorination of VOCs including TCE.

The following background information was provided to ARS by HDR in an email transmitted onJuly 7, 2003. The site is a non-active facility with no sensitive structures within the area oftreatment. Groundwater impacted with mostly TCE has been identified beneath the Site.Previous assessment activities and a review of past practices indicate a source area of TCE insoils and groundwater. The investigation of this source area appears to be centered aroundmonitoring well MW-2S.

The Site geology consists of primarily medium stiff-to-stiff, medium to highly plastic clays toapproximately 17 feet bgs. Below the clays are layers of dense, well-graded sand and gravel,which alternate with layers of sandy, silty clay. Water is typically encountered in sand and gravelzones at 24-30 feet bgs. A clay aquiclude exists on-site at approximately 36 feet bgs.

An approximate 21,000-resource zone has been defined by HDR at the site, and targeted fortreatment. The area is shown in Figure 5 (provided by HDR). TCE impacted groundwateroccurs within this area from an estimated 24 to 38 ft bgs. In addition, a discrete 1-foot thickinterval of soil located within the vadose zone has also been identified requiring treatment.

The overall objective of the source zone treatment will be to reduce dissolved-phase TCEconcentrations to the maximum extent possible (with a target goal of 90%+ reduction). ARS isconfident that its FeroxSM process can achieve this remediation goal in a cost effective and timelyfashion.

I ARS Technologies, Inc. Page 1


HDR Engineering Site UtahJuly 11,2003

2.0 TECHNOLOGY BACKGROUND AND GENERAL TREATMENT APPROACH

2.1 Technology Background

Ferox?M Treatment TechnologyARS' FeroxSM technology is a patented (US# 5,975,798) treatment process for the in situreduction of halogenated organic compounds. The FeroxSM technology consists of the multi-phase injection and emplacement of specific quantities of highly reactive ZVI powder intosubsurface contaminant zones.

The technology is extremely safe to use, relies on a simple chemical treatment mechanism, hasno major adverse effects on the environment and its reaction end products are benign. Inaddition, with its long in situ residence reaction life, insitu treatment occurs for periods of severalyears to address additional contaminant mass loading that may result from the presence ofresidual source contamination.

ARS has well documented experience in applying the FeroxSM process at sites impacted by PCEand TCE. Several of these sites possess similar contaminant types and concentration levels wellin excess of that found at the former HDR site.

The significant advantages of FeroxSM over other in situ treatment methods such as chemicaloxidation is its long in situ residence reaction life and its ability to not be affected by natural soiloxidant demand. These benefits provide an inherent engineering factor of safety to addressvaried contaminant loading conditions, which are inherently found at halogenated hydrocarbonsites. In addition, once the FeroxSM system is installed, there is no remaining above groundsystems that require ongoing utilities, O&M and interference with long-term site redevelopment.

The ZVI that ARS uses in its FeroxSM applications is a reduced sponge iron blend powder, with avery high particle surface area. The ZVI particle's unique size, shape and elemental compositionresult in an extremely reactive material. ARS has documented the superior reactivity of this typeof powder through the performance of numerous laboratory tests.

Zero-Valent Iron Reduction of PCE and TCEThe reaction mechanism for the reduction of PCE and TCE begins with the corrosion of the ZVIpowder as it comes into contact with a water molecule. The products of corrosion are ferrousiron (Fe+2), hydrogen gas (H2), and a hydroxyl ion (OH"). The produced hydrogen gascombines with the halogenated organic compound (e.g. PCE and TCE) on the surface of acatalyst (iron powder, naturally occurring electron mediator, or unidentified constituents in thesoil organic matter) whereby the contaminant is dehalogenated. In addition to the dehalogenatedcompound, a proton (H+) and chloride ion (Cl~) are also produced. The proton then combineswith the hydroxyl ion, formed during the corrosion reaction, to reform a water molecule."Accordingly, the end products of this reaction are ferrous iron, chloride ions, and thedehalogenated compound. Through the reliance on naturally occurring substances present in the




soil that act as electron mediators, the target organic (i.e., PCE and TCE) does not have to be indirect contact with the ZVI powder to be treated.

As a result of the dehalogenation reaction above, changes to the groundwater geochemistryinclude slight elevation of pH, significant decrease of ORP, increase in chloride and decrease indissolved oxygen.

ARS' confidence in the Feroxsm process is substantiated by our direct experience in applying thetechnology at more than 9 Federal EPA and DOD facilities, with similar contaminants andenvironmental conditions as the HDR site. One of these projects was a successful demonstrationat the Marshall Space Flight Center's SA-2. TCE groundwater concentrations in the source zoneat this particular site were effectively reduced from 73,000 ug/1 to 3,400 ug/1 (95% reduction) inless than 1 year and 80% reductions were observed in three months.

Ferox*"1 Injection Methodov*

A critical component of the Ferox process is ensuring that the ZVI is distributed as uniformlyand at adequate concentrations within the subsurface in such a manner to initiate the productionand transfer of electrons, that results in treatment. To accomplish this distribution, ARSincorporates a gas-based delivery approach for the emplacement of the iron powder. Theemplacement method is equally as important as the chemical reduction mechanism. In addition,this delivery approach has performed extremely well at similar project applications at theMarshall Space Flight Center (Alabama), , Charleston Naval Complex (South Carolina) andPicatinny Arsenal (New Jersey).

In coarser unconsolidated sands and silty sand formations, the injected gas fluidizes theformation in the immediate vicinity of the injection point and the ZVI slurry is dispersed throughthe formation at greater distances from the injection point via advective dispersion andchanneling of the sediments.

As ZVI slurry (ZVI powder mixed with water) is blended into the gas stream above ground andbecomes atomized. Relatively low pressures are required to sustain the flow into the formation.The FeroxSM atomization apparatus consists of a down hole injector system, consisting ofstraddle packers, and an injection nozzle, which allows for the focused injection to occur at anydepth interval. Depending upon the in situ pressures and matrix response to the gas flow, slurryfeed rates up to 40 gpm is achievable with ARS' commercial equipment.

2.2 General Treatment Approach

The treatment approach for will consist of the injection of approximately 122,000 Ibs of ZVIpowder. The injections will occur over discrete 30-inch intervals from 24 to 38 ft bgs withineach injection point using a total of 30 injection points to treat the target area. In addition, oneinjection interval will be used to emplace iron in the vadose zone. Each 30-inch interval will beisolated using straddle packers. The ZVI powder will be mixed with potable water at the groundsurface, atomized using nitrogen gas and then injected through a proprietary nozzle locatedbetween the packers. The bottom interval of each borehole will be addressed first. Once the




desired amount of ZVI powder has been delivered into a 30-inch interval, the straddle packersystem will be raised 30-inches and the process repeated.

The amount of ZVI needed was derived based on the mass of TCE in each plume1 and a ZVI toTCE mass ratio (known as the "iron to mass ratio") of 1,700:1 for the treatment. A higher iron tomass ratio was selected to ensure the iron will serve to treat any residual CVOC's that maymigrate into the source area or become mobilized during the treatment process. Based on ARS'experience with similar sites including numerous TCE projects and the results of manylaboratory treatability studies, ARS is confident that the proposed iron to mass ratios will resultin the 90 percent mass reduction over an approximate 1-year period,

ARS realizes that a 90 percent reduction will not result in achieving MCL target levels of 5 ppb,however, the emplacement of the ZVI will significantly lower TCE concentrations, while at thesame time change the subsurface environment to conditions more favorable to anaerobicdegradation. These changes include lowering the oxidation-reduction potential (redox) of thesaturated zone to the point where anaerobic dechlorination (possibly as low as methane reducingconditions) of the remaining TCE should occur and the introduction of hydrogen into the aquiferto stimulate microbial activity. In addition, it is expected that the ZVI powder will remain in thegroundwater for several years, thus sustaining anaerobic conditions for a long period of time andallowing the iron to continue to react with VOCs that may migrate into the treatment zone fromupgradient ground water and/or from the vadose zone (assuming that the chosen remedy for thevadose zone has been successful and that only minor amounts of TCE continue to migrate fromthe vadose zone into the groundwater). Therefore, the combination of the 90 percent reductionof TCE concentrations, the fact the ZVI powder will drive the redox potential significantlylower, and the long retention time of the powder should allow for the approval of naturalattenuation as the long-term, final remedy for the site.

Our general approach to long-term performance monitoring would include the installation ofseveral additional monitoring wells. These new wells, along with existing wells MW-2S, MW-3S and MW-4S should be sampled two weeks after the injections are complete and thenquarterly thereafter for one year (total of five sampling events). Groundwater samples collectedfrom these wells should be analyzed for VOCs, total and dissolved iron, chloride, redox,dissolved oxygen (DO), pH, temperature and conductivity.

1 The mass of TCE in the target source area was estimated at 71 Ibs. The mass for the GW component wasderived based on an average TCE concentrations of 2 mg/1 and a vadose zone mass of 59 Ibs.




3.0 SCOPE OF WORK

ARS has divided the project into the following seven tasks:

1 - Submittals and Permitting2 - Pre-Mobilization3 - Mobilization and Demobilization

O\jJ

4 - Ferox Field Application5 - Performance Monitoring6 - Reporting7 - Project Management

These tasks will include all labor, materials, equipment, documents, subcontractors and any otherappurtenances associated with completing each task, unless specified below.

The following is a description of what these tasks will include.

Task 1 - Submittals and Permitting This task includes preparation and submittal of pre-construction documents, including a Site Specific Health and Safety Plan and all documentsrequired for the project. This task also includes all technical support to HDR in the preparationof required permits including drilling permits and any underground injection control (U1C)permits.

Task 2 - Pre-Mobilization This task mostly includes equipment and materialprocurement, travel and living arrangements, subcontractor arrangements, shipping of materialsand supplies, equipment preparation, testing and packing, and arrangement for the shipment ofthe ZVI powder directly to the Site. Typically 3-5 weeks are required to complete theseactivities.

Task 3 - Mobilization and Demobilization The equipment and labor will be mobilizedfrom both our New Jersey and North Carolina (Durham) warehouses. The mobilization includestwo field vehicles, drilling equipment, an equipment trailer and our proprietary FeroxSM trailerand PF module along with other necessary supplies and equipment. All equipment mobilized tothe Site will be able be used within the treatment area. This task also includes:

• two days in the field to accept delivery of materials and equipment, set up and test theFeroxSM system, and get it ready for the full-scale application,

• tear down and final decontamination of equipment at the completion of the project, alongwith site cleanup, demobilization, and restocking and unloading of equipment back atARS' warehouses,

Task 4 - FeroxSM Field Application This task has been divided into two subtasksincluding:




4.1 Monitoring Well and Injection Point Installation4.2 Liquid Atomized Injection

4.1 Monitoring Well and Injection Point Installation This task includes theinstallation of two additional monitoring wells and thirty, 4-inch temporary injection points. Themonitoring well sub-task will occur three to four weeks prior to mobilization for the FeroxSM

injections (Subtask 4.2) so that HDR will have ample time to conduct baseline groundwatermonitoring.

Note the following:• ARS will perform all drilling.• All soil cuttings will be drummed and staged on-Site for classification and disposal.• All well development water, decontamination water, etc will be treated on-Site by HDR.

ARS will transport this water to a location chosen by HDR.

4.2 Liquid Atomized Injection This task will involve the liquid atomized injection of122,000 Ibs of ZVI powder. Based upon our experience with ZVI injections in similar geology,the target treatment area will require the use of 30 injection points. The vertical interval treatedwill be from 24 to 38 ft.

In order to complete the injections, the down hole straddle packer assembly and injection nozzle(i.e., injection assembly) will be lowered to the bottom of the temporary cased borehole (oneinjection point at a time will be completed). The 4-inch casing will be retracted upwardexposing the injection assembly to the formation. Once the packers are inflated and the discreteinjection zone (30-inches) is sealed off, the atomized injection will take place. Starting withnitrogen-gas only, the geologic zone surrounding the injection point will be fluidized for a periodof roughly 10 to 20 seconds. Without shutting off the gas flow, the ZVI slurry will be fed intothe flowing gas stream to be injected into the subsurface. The specified dosage for each injectionlocation will dictate the length of each injection. Once the specified dosage has been injected,the entire assembly will be raised 30-inches and the process repeated until the entire injectionpoint is complete.

CKjf

During each Ferox injection, the following system operational parameters will be monitoredand recorded:

• Down hole pressure response,• Injection pressure influence at surrounding monitoring wells,• Presence and magnitude of ground surface heave within and adjacent to the injection

point,• Depth and vertical interval of injection, and• ZVI dosage and nitrogen use

Other visual observations during injection will also be recorded. A summary of the operationalparameters are provided below.




Injection Pressure ResponseDuring each injection, a pressure transducer will be used to record data 8 times a second. Thisdata will be used to create a pressure response history curve from which the formation pressureresponse to the injection will be determined. The graphical representation of this data plottedover time provides information as to the in situ stresses of the formation corresponding to depth,as well as helping to evaluate the mechanism of iron emplacement.

Pressure Influence at Surrounding Monitoring WellsDuring the injections, pressure gauges will be placed at surrounding wells to monitor forpressure influence. Each pressure gauge is outfitted with a drag arm indicator that records themaximum pressure detected at the monitoring point during the injection. In addition, visualobservations will also be used to indicate pressure influence in surrounding wells. Existingmonitoring wells will be used for pressure observations.

Ground Surface HeaveGround surface heave monitoring will be conducted during each injection using surveyingtransits in conjunction with heave rods. The heave rods will be placed at locations of varyingradial distance from the injection well. During each injection event, the rods will be observed forthe maximum amount of upward motion (surface heave) and the post-injection resting position(residual heave). Ground surface heave monitoring data provide additional information that canbe used to help assess the extent of injection influence.

Depth and Vertical IntervalThe target interval (24 to 38 ft bgs) will be subdivided into smaller discrete target zones andaddressed separately. These zones will be determined prior to the start of fieldwork and for thesake of this proposal are expected to be 30-inches in length. The type of packers used to isolatethe interval will limit the length of these zones. Larger packers typically require a longerinterval. The depth of each zone and the vertical length of each interval will be recorded.

ZVI Dosage and Nitrogen UseDuring each targeted injection, ARS will observe and record the amount of ZVI emplaced toensure that the targeted treatments are met. In addition, ARS will periodically evaluate thenitrogen use rate

Note the following:• ARS will conduct casing removal during the injections and borehole abandonment.• All decontamination water will be treated on-Site by HDR. ARS will transport this water

to a location chosen by HDR.

Task 5 - Performance Monitoring Our cost estimate assumes HDR will conduct fiveperformance-monitoring events. The wells would be sampled two weeks after the injections arecomplete and then quarterly thereafter for one year (total of five sampling events). Groundwatersamples collected from these wells should be analyzed for VOCs, total and dissolved iron,chloride, redox, DO, pH, temperature and conductivity.




This data will be used to evaluate the performance of the treatment application. The mostobvious indication of the effectiveness of the method will be VOC reductions. As a result of theinjection process, ARS typically observes increases in VOC levels immediately after theinjections occur. This is the result of the mobilization of additional contaminant resulting thetemporary agitation and mixing of the soils. This is actually a positive event since thiscontaminant is no more readily exposed to the ZVI. Other effects will include the lowering ofDO and redox levels and an increase in chloride levels.

Task 6 - Reporting The task has been divided into three subtasks including:

6.1 Installation Summary Report6.2 Quarterly Performance Monitoring Reports6.3 Final Report

6.1 Installation Summary Report ARS will submit to HDR an Installation SummaryReport, which will also include a discussion of the first performance monitoring event. Thisreport will be submitted approximately eight weeks after the injections have been completed andwill include:

Oil*

• summary of Ferox injections, procedures and dosages• plot plan showing injection and monitoring well locations• tables summarizing injection point depths, injection intervals, iron dosages, pressure

responses, etc.• tables summarizing groundwater analytical results• monitoring well construction details

6.2 Quarterly Performance Monitoring Reports These reports will present adiscussion of the effectiveness of the FeroxSM process. Each report will be submittedapproximately 4 to 5 weeks after the groundwater results have been provided to ARS.

6.3 Final Report This report will integrate all of the previously submitted reports along withtabulated summaries of groundwater analytical data. A summary of the overall effectiveness ofthe FeroxSM process will be presented along with a discussion of the achievement of theremediation objectives and the ability of any remaining TCE to be naturally attenuated. Thesubmirtal date for the final report is to be decided.

All reports will be submitted to HDR in draft form.

Task 7 - Project Management The task includes management throughout the duration ofthe project and includes two meetings at the HDR facility. The ARS project manager will attendthese meetings. The first meeting will be held prior to the start of fieldwork. The time of thesecond meeting shall be decided at a later date.




4.0 ESTIMATED PROJECT COST

ARS will conduct this work on a lump sum and unit rate basis. The estimated cost breakdown toimplement the six tasks described in Section 3.0 is $575,500 and is detailed below.

Task Cost1 - Submittals, Permitting, Engineering (LS) $25,0002 - Pre-mobilization (LS) $20,0003 - Mobilization and Demobilization (LS) , $ 15,0004 - FeroxSM Field Application

4.1 Mon Well and Inject Point Install $35,0004.2 Liquid Atomized Injection (15 days @ $ 10,000/day) $ 150,000

ZVI powder (122,000 Ibs @ $1.53/lb) $186,000- Nitrogen (2,300;000 cf @ $0.05/cf) $115,000

Waste Staging/OnSite Transport (10 drums @ $250/drum) $2,5006 - Reporting

6.1 Installation Summary Report (LS) $7,0006.2 Performance Monitoring Reports (4 @$1,500/report) $6,0006.3 Final Report (LS) $4,000

7 - Proj ect Management (LS) $10,000TOTAL $575,500

LS = lump sum

Unit cost items and factors that may impact the above estimate are discussed below.

1. Included in the above price is the cost for 122,000 pounds of ZVI powder at a rate of$1.53 per pound.

2. The amount of nitrogen required to atomize the slurry and inject it into the formation ishighly dependent upon the formation permeability and the rate at which the formationcan accept the ZVI. The above cost includes 2.3 Million ft3 of nitrogen. This assumesthe following approximations.

3. The presence of man-made and non-naturally occurring geologic conditions potentiallymay cause the injected ZVI to migrate to the surface prematurely (a.k.a. day lighting).Using ARS' atomized delivery system, our approach offers the greatest and safest levelof control in the distribution of ZVI within the subsurface. However, if extensive non-naturally occurring disruptions such as existing old utility trenches, previously excavatedareas, improperly abandoned boreholes, waste pits and sumps, etc are present within thetreatment zone, ARS will be limited from a safety perspective by the quantity of ZVI itcan emplace into the subsurface. Without having intimate knowledge of the Site, ARScannot predict the presence or location of all man-made and non-naturally occurringgeologic conditions that may effect the emplacement of the ZVI powder. However, theZVI slurry is non-toxic and will not harm the environment if day lighting occurs.ARS will use its experience to minimize the chance of day lighting by appropriatelyadjusting pressure and flow rates as needed.

4. The above cost assumes that we can complete the drilling and liquid atomized injectionsin 15 days (not including demobilization/mobilization, setup and tear down time. The




liquid atomized injection rate is highly dependent upon the rate of ZVI slurry injection,which is mostly a function of how quickly the formation can accept the slurry, withoutover pressurizing the formation. In addition, if the field activities take longer thanestimated for any reason beyond the control of ARS (such as, but not limited to weather,delays resulting from HDR and/or regulatory agencies, unexpected day lighting of theslurry, etc) the above estimated costs may be higher.

5. The use of ZVI for chlorinated VOC reduction offers the best advantage over other in situtreatment processes when treating halogenated hydrocarbons. Since our ZVI materialcontinues to provide in situ treatment long after the injections have been completed,moderate concentration spikes due to any residual contaminant mobilization will betreated by the application. However, if significant VOC mass loading occurs after theinjections due to upgradient or unremediated vadose sources or accessing of hydraulicallyisolated zones, injecti, the timeframe to reach target cleanup levels may take longer thandesigned or additional ZVI may be required. Additional ZVI injections to address theseconditions beyond ARS' control are not included in the cost of our estimate.

6. It is our understanding that HDR will conduct all baseline and post injection GWmonitoring including the sampling of any new wells installed as outlined above.

7. It has been assumed that vadose zone soils possess a moisture contact of 12% or more.

Other cost assumptions include:

• All utilities will be located and marked by HDR. ARS will not be responsible fordamage caused to unknown, unmarked or improperly marked utilities or subsurfacestructures.

• Our estimate assumes that HDR will complete any UIC permit application and that noadditional subsurface investigations of any kind are required to complete the UIC permit.

• 120V power and a potable water source will be available within the immediate vicinity ofthe work area. Sanitary facilities are also available on-Site.

• All non-hazardous solid waste will be disposed of on-Site at a location selected by HDR.• Steam cleaning or pressure washing of down hole tools and equipment will not be

required between boreholes. ARS will pressure wash all down hole tools at the end ofthe project and as needed.

• HDR is to sign all waste manifests.• Our estimate does not include the decommissioning of any monitoring wells at the end of

the project.• All regulatory correspondence and interactions will be handled by HDR.• Complete and unhindered access to the project Site will be available.• Normal working hours is expected. ARS may work longer than 8 hours per day and may

work weekends, if needed.• Level D+ PPE is expected. The use of higher levels of PPE could result in longer field

times.




5.0 PROJECT SCHEDULE

From the time of contract award and execution, to the submittal of the Installation SummaryReport, approximately 30 weeks will pass, which is just over seven months. This includesobtaining the necessary permits for the project. The following outlines a proposed schedule forour approach.

Task Completion in Weeks Following Authorization1 - Submittals and Permitting Support2 — Pre-mobilization (assuming all permits obtained within 10 weeks of submittal) 173 - FeroxSM Field Application 244-Performance Monitoring (1st event) 265 - Reporting (Submit Installation Summaiy-Report) - 30

I ARS Technologies, Inc Page 11

Appendix DCapture Analysis Technical Memorandum

W S Hatch Co HDR Engineering, IncFocused Feasibility Study Final Report July 2004

Final Technical MemorandumCapture Analysis at the W.S. Hatch Co. SiteWoods Cross, Utah

INTRODUCTIONThis memorandum address the groundwater extraction remedies discussed underAlternative 7 of the Hatchco Focused Feasibility Study (FFS). In order to assess theremedial alternatives considered in the FFS, a capture analysis utilizing particle trackingwas conducted within the calibrated flow model (see Hatchco Remedial Investigation,Appendix K).

The numerical groundwater model was developed using Visual MODFLOW Pro(Version 3.0, Waterloo Hydrogeologic, 2002), an interface for the three-dimensional,modeling program, MODFLOW. The interface uses the USGS developed MODFLOW-2000 finite difference code. The mass transport numeric engine used in this model isRT3Dv2.5, a program for simulating reactive multi-species mass transport in three-dimensional aquifers developed for the Battelle Memorial Institute, Pacific NorthwestNational Laboratory. The numerical model is described in detail in the GroundwaterModeling Technical Memorandum presented as Appendix K of the Hatchco RemedialInvestigation Report.

PUMPING RATE CALCULATIONTo calculate a feasible pumping rate for an extraction well at the Hatch Site (the Site), thefollowing equation was implemented (Theis, 1963):

T = (114.6Q/s)[-0.577-ln(1.87r2S/Tt)J

Where:Q is the pumping rate (gallons per minute, gpm)t is the period of pumping (days)r is the radius of the pumping well (feet)s is the drawdown (feet)T is the aquifer transmissivity (gallons per day per foot)S is the specific yield (dimensionless)

Hydraulic conductivity values were derived from slug tests and ranged from 1.375 to67.92 ft/day. Input values for the equation and the range of results using the highest andlowest hydraulic conductivity values are shown in Table 1.

Groundwater Modeling HDR Engineering, Inc.Technical Memorandum 1

Table 1 - Input Parameters for Pumping Rate CalculationInput ParameterThickness, ftHydraulic Cond., ft2/dTransmissivity, gpd/ftRadius of well, ftSpecific Yield, unitlessTime, yearsDrawdown, ftPumping Rate, gpm

KL<>W10

1.375102.850.1667

0.13153

0.15

KHJEH10

67.925080.40.1667

0.13153

6.17

CAPTURE ANALYSISThe above range of pumping rates was used to design a pumping scheme at the Site.

. Initially,, a .line, of extractipnwells at the downgradient boundary was conceptualized.Flow rates at each well were adjusted to maximize capture of the Hatch plume whileminimizing capture of the commingled plume to the north. The resulting flow rates at theseven wells ranged from approximately 0.8 to 1.3 gpm. However, within the model,complete capture of Site groundwater significantly impacted the overlapping contaminantplume to the north as illustrated on Figure 1. As a result, a pumping scheme involvingone well with a higher flow rate was examined.

The single well system involves an extraction well located near monitoring well MW-3S.Within the model, a range of pumping rates was applied to the well and the effect on boththe Site groundwater and off-Site groundwater were analyzed. Using the results of thecapture analysis, a rate of approximately 3 gpm was selected based on capture achievedwithin the Site, as well as significance of impact to the northern plume (Figure 2).

CONTAMINANT CONCENTRATION ANALYSISIn addition to the capture analysis, the model was used to simulate the timeframe inwhich maximum contaminant levels (MCLs) would be achieved as a result of remedialaction. This simulation assumed complete capture within the Site boundaries such that nocontaminants leave the Site after year 2003. The resulting date at which MCL complianceis predicted is 2017 (Figures 3-5). Table 2 presents this information in addition to theoriginal dates of MCL compliance cited in the Groundwater Modeling TechnicalMemorandum (see Hatchco Remedial Investigation, Appendix K).

Table 2 - Dates of MCL Compliance

Action*

No Action

Source ScenarioAll ScenariosScenario 1Scenario 2Scenario 3

Date2017202220272057

*Assumes complete capture on-Site beginning in 2003.

Groundwater ModelingTechnical Memorandum

HDR Engineering, Inc.2

REFERENCES

HDR, 2003. Former W.S. Hatch Co. Facility, Draft Remedial Investigation Volume I.February, 2003.

Theis, C.V. 1963. Methods of Determining Permeability, Transmissibility andDrawdown, United States Geological Survey Water-Supply Paper 1536-1, 341p.

Waterloo Hydrogeologic. Visual MODFLOW Pro. 2002.

Ground water Modeling HDR Engineering, Inc.Technical Memorandum 3


WITHOUT PUMPING

FLOW DIRECTION

APPROXIMATE" SOUTHERN EXIENT-~OF NORTHERN PLUME '•"

m¥\V—

XW-1

LEGEND


PARTICLE PATHLINE


HATCHCO BOUNDARY


WITH PUMPING (8 gpm total)

APPROXIMATE SOUTHERN EXTENT-OF NORTHERN PLUME


Particle Trackirlg PathlinesSeven Well System

/UHTnunn \ Capture Analysis Technical Memorandum( HAIUHLU WS Hatch Co.

Woods'Cross, Utah

Date

JULY 2003

Figure

PARTICLE TRACKING PATHLINESWITHOUT PUMPING


WITH PUMPING (APPROX. 3 gpm)

APPROXIMATE SOUTHERN EXTENT"OF NORTHERN PLUME '""

FLOW DIRECTION ;

T)Di/i

APPROXIMATE SOUTHERN EXTE-NT-OF NORTHERN PLUME r~"

XW-1

LEGEND


PARTICLE PATHLINE


HATCHCO BOUNDARY

NOTE: SOME PATJHLINES REMOVED..FOR CLARITY


Particle Trackirjg PathlinesSingle Well System

ÛfiTnunn^ Capture Analysis Technical MemorandumHfllUHbU ws riatch Co.

Woods Cross, Utah

Date

JULY 2003

Figure

Documents

Former W.S. Hatch CO. Facility ( HATCHCO ) Woods Cross, Utah … · 2019-12-03 · HATCHCO Est. 1936 P.O. BOX 50539 • AMARILLO, TEXAS 79159 • 806-354-5678 Former W.S. Hatch CO