Mr. Kyle Barber Arkansas Department of Environmental ......Jan 26, 2017 · Dear Mr. Barber, Based on a recent phone conversation with Charles Johnson, Clean Harbors El Dorado, LLC

Clean Harbors El Dorado, LLC 309 American Circle El Dorado, AR 71730 www.cleanharbors.com

“People and Technology Creating a Better Environment”

January 27, 2017 Mr. Kyle Barber Arkansas Department of Environmental Quality 5301 Northshore Drive North Little Rock, AR 72118-5317 Transmit via email; [email protected] RE: Clean Harbors El Dorado, LLC NPDES CAP Dear Mr. Barber, Based on a recent phone conversation with Charles Johnson, Clean Harbors El Dorado, LLC provided language to clarify the Corrective Action Plan (CAP) inspection. Attached are an updated CAP and Appendix E that codify that clarification. Should you have any questions, please contact me at 513-823-2280 or at [email protected]. I certify under penalty of law that this document and any/all attachments were prepared under my direction or supervision according to a system designed to assure that qualified personnel properly gather and evaluate the information submitted. Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the information, the information submitted is, to the best of my knowledge and belief, true, accurate and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisonment for knowing violations. Sincerely, Michael Crisenbery, CHMM Vice President, Compliance Clean Harbors Environmental Services, Inc. Cc: File Kathy Shoemaker – CHED Dan Roblee – CHED Marty Smith - CHES

mailto:[email protected]

mailto:[email protected]

Appendix E:

East Conveyance Ditch Maintenance Plan

Prepared for:

309 American Circle

El Dorado, Arkansas 71730

Prepared by:

1422 Washington Avenue Golden, CO 80401

Project No. 082-108

Revised January 26, 2017

CHED Outfall 009 Corrective Action Plan Appendix E O&M Plan January 2017

11/16/2016 i

TABLE OF CONTENTS 1 INTRODUCTION .............................................................................................................................................. 1

2 BACKGROUND ................................................................................................................................................. 1

2.1 PRE-CONSTRUCTION EAST CONVEYANCE DITCH ......................................................................................... 2 2.2 POST-CONSTRUCTION EAST CONVEYANCE DITCH ....................................................................................... 3 2.3 AS-BUILT SURVEY ........................................................................................................................................ 4

3 INSPECTION AND MAINTENANCE OF SEEP REMEDIES ..................................................................... 4

3.1 INSPECTION FOR DEGRADATION ................................................................................................................... 5 3.1.1 Temperature Change ............................................................................................................................... 5 3.1.2 Wear and Tear ......................................................................................................................................... 6 3.1.3 Burrowing Animals .................................................................................................................................. 6 3.1.4 Erosion and Scour Adjacent to the Lined Ditch ...................................................................................... 6 3.1.5 Groundwater Seeps Adjacent to the Lined Ditch ..................................................................................... 6

4 REPAIR PROCEDURES AND TECHNIQUES ............................................................................................. 7

4.1 CONCRETE RESTORATION ............................................................................................................................. 8 4.2 DRAINAGE PRESERVATION ........................................................................................................................... 8

5 REFERENCES ................................................................................................................................................. 10

LIST OF FIGURES

FIGURE 1: SITE LOCATION MAP FIGURE 2: SITE BASE MAP FIGURE 3: LINED CHANNEL CONTAINED FLOW EAST CONVEYANCE 100 CFS ENGINEERED

DESIGN

LIST OF APPENDICES

ATTACHMENT A: INSPECTION FORM


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11 IINNTTRROODDUUCCTTIIOONN

This East Conveyance Ditch Maintenance Plan (Maintenance Plan) has been prepared as Appendix E: Maintenance Plan within the NPDES Outfall 009 Corrective Action Plan (CAP report) last revised in December 2016 for the Clean Harbors El Dorado, LLC (CHED) property located at 309 American Circle in El Dorado, Arkansas 71730 (Site). The objective of this document is to outline a maintenance program for the East Conveyance Ditch to be completed as part of corrective measures designed to eliminate groundwater seeps in the southeast quadrant of the Site. As the East Conveyance Ditch is a passive system, there is not an Operation component to this document. Maintenance tasks will begin at the conclusion of the ditch rehabilitation and other seep remedy construction projects. The primary objective of this Maintenance Plan is to monitor the East Conveyance Ditch and surrounding area for groundwater seeps. Other objectives of this Maintenance Plan are to maintain the integrity of the East Conveyance Ditch structure, prevent the accumulation of obstructing sediments and vegetation in the ditch; and early identification of erosion and scour in the area adjacent to the East Conveyance ditch that have the potential to introduce groundwater seeps to the surface in these areas. Maintenance will be conducted based on the findings of field observations and will be performed as needed depending on the severity of the damage and potential for environmental impacts.

22 BBAACCKKGGRROOUUNNDD

This Maintenance Plan has been prepared as part of the CAP report which describes a plan for corrective action to eliminate excursions of Lead and 1,2-Dichloroethane in samples collected from NPDES Permitted Outfall 009 for the Site. CHED currently owns the property where it conducts hazardous waste management operations. CHED has authorization to discharge storm water passing through the Site and stormwater retained at the Site to local surface water features under the National Pollutant Discharge Elimination System (NPDES) and the Arkansas Water and Air Pollution Control Act Permit No. AR0037800, AFIN: 70-00098 administered by the Arkansas Department of Environmental Quality (ADEQ). Water quality criteria established by the permit was first exceeded in water quality samples collected in October 2012. Intermittent water quality excursions since October 2012 have been examined and the steps required to achieve outfall discharge water quality compliance by addressing the sources of contamination is delineated in the CAP. The CAP serves the purpose of fulfilling the request by the


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ADEQ for a Corrective Action Plan (CAP). This Maintenance Plan fulfills the request by the ADEQ to prepare an Operation and Maintenance Plan as stated in Comment Number 1 of the letter RE: Request for Revised Corrective Action Plan dated October 17, 2016. CHED operates a hazardous waste treatment and incineration facility on the northern portion of the Site. The Site is situated 1.5 miles southeast of the city of El Dorado, Arkansas and occupies an area of approximately ±320.0 acres. Figure 1: Site Location Map provides the general location of CHED hazardous waste treatment and storage site relative to the city. A base map of the Site, including property boundaries, has been placed on the aerial image provided in Figure 2: Site Base Map. The property is bounded on the west and northwest by residential areas of the city of El Dorado and the north by an industrial zone. The Site eastern boundary is Boggy Creek and associated marshes. Fallow fields and forest are present south of the facility operations. The East Conveyance Ditch is located in the southern half of the site on the west side of Boggy Creek. The Site has been operationally divided into two (2) areas segregated by a the operational east-west trending Union Pacific railroad tracks (noted on Figure 2: Site Base Map). Hazardous waste management activities are conducted within the North Area; these facility operations are regulated by the Resource Conservation and Recovery Act (RCRA), including the storage, treatment, and high temperature incineration of hazardous and non-hazardous waste materials. The South Area, the focus drainage area feeding East Conveyance Ditch, contains capped landfill areas, storm water management facilities, the firewater pond, and other currently unused lands.

2.1 PRE-CONSTRUCTION EAST CONVEYANCE DITCH

As of the date of this Monitoring Plan, the East Conveyance Ditch is an earthen ditch that is gently sloping eastward at approximately 0.37 percent and that is approximately 413.0 feet in length to the weir at NPDES Outfall 009. The ditch is approximately 12 feet wide and averages approximately 2.0 feet deep and incised beneath the groundwater table elevation. The banks are lined with grasses, trees, and shrubs. Stormwater conveyed by the ditch is discharged at the weir located at NPDES Outfall 009. The weir is a V-notch weir monitored daily for measuring the rate of discharge to Boggy Creek. The low-land area north of the East Conveyance floods with storm water frequently while the East Service Road has been known to flood infrequently as observed by facility personnel.


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2.2 POST-CONSTRUCTION EAST CONVEYANCE DITCH

As described in the CAP Report, a lined channel option was determined to be the best option for eliminating seeps in the East Conveyance Ditch. This alternative raises the storm water conveyance flow line above the local groundwater table which severs the potential for seeps. An HDPE liner will limit local groundwater and/or LNAPL derived from seeps to encroach on storm water passing through the East Conveyance to Boggy Creek during high water table periods. It is anticipated that the liner is a precautionary measure for the extremely rare condition when the water table is exceptionally high. As the liner is to be placed above the typical groundwater table elevation, groundwater is not anticipated to surface adjacent to the new ditch alignment as groundwater does not currently surface adjacent to the existing ditch. The HDPE liner will be covered by a four (4) inch thick layer of concrete grout encased in a Fabriform liner. The East Conveyance Ditch is to be constructed by first compacting and grading the subgrade soil. The subgrade will then be lined with 40 mil HDPE. The HDPE liner will then be overlain by 4 inch thick Fabriform Unimat. Unimat is a type of fabric-formed concrete that results from pumping a highly fluid concrete mix into woven polypropylene fabric bags. The polypropylene bags are UV resistant and not only provide the concrete form of the final ditch lining, the bags become the concrete reinforcement. During filling of the bags, the fibers become coated with fluid concrete adding a further degree of UV protection. As the concrete is continuously reinforced top and bottom, the Unimat should be free of cracks for the lifetime of the product which is estimated in excess of 30 years. Nonetheless, the Fabriform should be inspected regularly similar to typically constructed concrete lined ditches. The Lined Channel will extend from the East Service Road Crossing past the Outfall 009 Weir ending approximately 30 feet upgradient of the bank of Boggy Creek. An engineered design schematic of the proposed Lined Channel Elevated Conveyance scenario has been included as Figure 3: Lined Channel Contained Flow East Conveyance 100 cfs Engineered Design. The capacity of the designed Lined Channel will be 100 cfs in keeping with the capacity of the existing Double Culverts under the East Service Road.


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2.3 AS-BUILT SURVEY

An as-built survey of the constructed ditch is to be completed at the conclusion of construction. The as-built survey will serve as a reference to identify changes in elevation of the East Conveyance Ditch and control points will be used to establish coordinate and elevation control for the purpose of future monitoring activities. A control point should be located on either side of the constructed ditch roughly mid-way between the start and end point of the completed ditch within sight distance between the start and end of new construction. A copy of the as-built survey is to be kept with this Maintenance Plan for future use in identifying the location and naming areas that require ongoing observation. The as-built survey is to include points every 25 feet along the flow line of the ditch with corresponding toe-of-slope and top-of-slope shots from the start of new construction to the end of new construction. A topographic survey is to be completed in a 25 foot grid pattern for the area extending 50 feet north and south of the ditch top-of-slope on either side and 20 feet upgradient of the west side of the East Service Road to 20 feet 20 feet downgradient of the weir.

33 IINNSSPPEECCTTIIOONN AANNDD MMAAIINNTTEENNAANNCCEE OOFF SSEEEEPP RREEMMEEDDIIEESS

The goal of this maintenance plan is to monitor the East Conveyance Ditch and surrounding area for groundwater seeps in addition to maintaining the integrity of the concrete lining. The ditch and surrounding area will be inspected after significant rain events or monthly during dry periods. A significant rain event is characterized by two (2) inches or more of rainfall in a twenty-four (24) hour period. An onsite rain gauge will be checked daily for these criteria. If there has been no rainfall within a calendar month following the prior inspection then the facility will conduct the survey at least once monthly for those dry months. Inspections will occur within 48 hours of rainfall cessation. Some waiting time is essential after a storm to allow for local drainage to be complete enough to be able to see the surface of the soil for inspection purposes. This is especially important in looking for scoured areas and seeps. Inspections will focus on the East Conveyance Ditch starting at the west side of the East Service Road and continue eastward to the end of the lined ditch and will also include observing the transition of the east end of the ditch out toward the Boggy Creek embankment. The Ditch is to be visually inspected and repairs made as needed. The cap inspection and maintenance checklist is included as Attachment A: Inspection Form. This form, or a comparable electronic form, will be used during field activities to note possible areas of concern regarding the ditch and surrounding area. Copies of the as-built map should be marked with the location


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of field items of concern. These items are to be monitored if minor and repaired to prevent further deterioration of the concrete ditch covering. Maintenance checklists and maps will be retained onsite for reference and comparison of items requiring ongoing monitoring. During final construction close-out activities, the East Conveyance Ditch is to be inspected by both methodical visual inspection and land surveying. These inspections will look for possible ditch lining defects, damage to the lining due to operations at the site, and differential settlement. Visual inspection of the ditch will be conducted by field personnel. Any areas of concern will be recorded in a log book, on field inspection forms, and on a site map. Maintenance and repair will be conducted as required. The land survey described above is to be completed at the conclusion of construction activities. Additional survey data will be gathered as needed to verify or monitor detrimental changes in elevation. The initial survey elevations will be compared over time to determine a rate of settling. Very minor initial uniform settling is anticipated during the first year following construction. Differential settlement of the concrete ditch lining could cause localized subsurface change and a subsequent change in elevation. Areas of differential settlement will be monitored for signs of stress. The following sections outline basic guidelines for the inspection and maintenance of the concrete ditch and surrounding area along with quality assurance procedures to ensure proper repair. These sections also provide guidance for the maintenance personnel responsible for inspecting and maintaining the constructed remedy improvements.

3.1 INSPECTION FOR DEGRADATION

There are several factors that could affect the integrity of the concrete ditch lining. Possible causes of degradation of the lining and needed repairs are listed in the following sections.

3.1.1 Temperature Change

Temperature change can cause expansion and contraction of the concrete, resulting in cracking. Because the site is located in an area that experiences freezing temperatures in the colder months, and the subsequent thawing of those temperatures, the concrete ditch lining is susceptible to cracking due to these


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extremes. Timely repair of small cracks is necessary, as even small cracks can expand and allow more infiltration into the concrete matrix, creating further concrete degradation.

3.1.2 Wear and Tear

Wear and tear may play a part in the longevity of the concrete ditch lining. Wear and tear due to flowing water and abrasive sediment may damage the concrete lining. Signs of wear and tear on the final cover are to be noted during the inspections and the concrete will be repaired if necessary.

3.1.3 Burrowing Animals

Burrowing animals may impact the integrity of the final ditch cover. Burrowing animals will be removed according to local laws to prevent damage. After the animal has been removed, the burrow is to be inspected to determine if the ditch lining may have been impacted or if a large void space has been created beneath the liner. Damage to the ditch is to be noted during the inspections and the concrete will be repaired if necessary.

3.1.4 Erosion and Scour Adjacent to the Lined Ditch

Erosion Control measures are to be emplaced where the soil and vegetation has been disturbed adjacent to the ditch work areas. Erosion control measures planned at the Site include placement of erosion control mat and vegetation grasses and wild flowers. In locations of greater anticipated water velocity anchored filter fabric and rip rap is to be emplaced adjacent to the East Conveyance Ditch. Erosion control measures are critical in the prevention of soil erosion and scour. Minor erosion control damage can escalate during subsequent storms and expose deeper soil and potentially groundwater if not repaired in a timely manner.

3.1.5 Groundwater Seeps Adjacent to the Lined Ditch

Groundwater seeps in the low lying area adjacent to the East Conveyance ditch are of particular concern to the ADEQ and prevention of such seeps is to be monitored. It should be noted that groundwater does not currently seep in the areas directly adjacent to the East Conveyance ditch and that a lined ditch


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constructed primarily above the water table is not anticipated to have an influence that would induce new seepage in this area. Groundwater seepage may be difficult to definitively pinpoint as puddles of water may simply be due to lack of drainage, low soil permeability, and low evaporation rates in a humid climate. Under these circumstances, it is best to note the location of the apparent seep and monitor the location for persistence during dry periods of weather. The location should be marked on a copy of the as-built map and noted on the field form. Details to note during the inspection of a potential groundwater seep are the existence of ground settlement, exposed soil due to erosion or scour, vegetation that is inconsistent with the surroundings, and potential cause. The topographic grid documented in the as-built survey may be compared to new survey to judge the depth of settlement. Potential seep locations should be monitored periodically, and if determined to be a ground water seep the area should be repaired within 60 days of the determination. Repairs would include correction of the underlying cause, likely fill soil to return the area to an elevation above the groundwater elevation, followed by erosion control mat and revegetation.

44 RREEPPAAIIRR PPRROOCCEEDDUURREESS AANNDD TTEECCHHNNIIQQUUEESS

Cracks are likely to be the most common form of damage encountered in the concrete ditch. Even small cracks can allow infiltration of water or other material below the concrete. Due to freeze – thaw activity, small cracks can quickly become larger if not repaired in a timely manner. Using the descriptions provided in the EPA Technical Guidance Document Determining the Integrity of Concrete Sumps, the suggested width ranges for classifying cracks are: Fine: less than 1 millimeter Medium: between 1 and 2 millimeters Wide: over 2 millimeters Attachment A: Inspection Form will be the field form used to inspect the cap and track maintenance. Included in Attachment A is the classification of crack widths ranges. A systematic approach will be used to address repairs of the concrete lined ditch:

Step 1: Determine the cause(s) of damage


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Step 2: Evaluate the extent of damage Step 3: Evaluate the need to repair Step 4: Select the repair method Step 5: Prepare the old concrete for repair Step 6: Apply the repair method Step 7: Cure the repair properly

The following repair techniques will most likely be used to fix potential problems listed in field form found as Attachment A. These techniques provide guidance to inspectors and will be made as needed to prevent a failure in the ditch performance. The cause of damage should be evaluated and considered in all instances of cracking Fabriform due to the presence of reinforcing fabric on the top and bottom of the liner system. Fixing the cause is equally if not more important than fixing the cracks. Note that the ditch flow line is above the highest estimated water table with a protective HDPE liner beneath. Groundwater seepage to the surface from beneath the ditch is not anticipated due to general increase in the ground elevation.

4.1 CONCRETE RESTORATION

Concrete restoration consists of grinding and any combination of repair, grout subsealing, dowel retrofit of cracks, and cleaning and sealing of the seams. The purpose of restoration is to repair any isolated failures. The following types of damage can be repaired with concrete pavement restoration practices (Reference Pavement Preventive Maintenance Guidelines):

• Extensive, high degree of punchouts or breaks • Extensive, severe pressure damage (>2” deep subsidence) • Extreme change in performance • Occasional, high degree of subsidence or upwelling

4.2 DRAINAGE PRESERVATION

This activity is intended to preserve and maintain the performance of the ditch drainage system. Drainage preservation consists of cleaning silt, debris, and vegetation from the ditch periodically. Accumulation of precipitation and ponding can be remedied by drainage preservation. Heavy equipment must not enter the


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ditch to perform cleaning activities as the weight of the equipment could rest on an unseen void space below the ditch resulting in cracked concrete or punch through. Sediment cleaning with a high pressure hose is recommended. Under no circumstances should sediment from cleaning operations be allowed to wash down the ditch to enter Boggy Creek.


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55 RREEFFEERREENNCCEESS

Arkansas Department of Environmental Quality, 2015. Letter sent by Kyle Barber (Enforcement Analyst Water Division, Enforcement Branch ADEQ) to Kathy Shoemaker (Senior Compliance Manager CHED) on May 18th 2015.The letter advised CHED that the ADEQ was requested a CAP to address effluent violations. NPDES Permit No.: AR0037800, AFIN: 70-00098 Request for Corrective Action Plan.

Arkansas Department of Environmental Quality, 2016a. Letter sent by Kyle Barber (Enforcement Analyst Water Division, Enforcement Branch ADEQ) to Kathy Shoemaker (Senior Compliance Manager CHED) on January 7th 2016.The letter advised CHED that the ADEQ had No Objection to Scoping Plan NPDES Permit AR0037800, AFIN 70-00098.

Arkansas Department of Environmental Quality, 2016b. Letter sent by Kyle Barber (Enforcement Analyst Water Division, Enforcement Branch ADEQ) to Dan Roblee (Facility General Manager CHED) on May 5th 2016. NPDES Permit Number AR0037800, AFIN 70-00098 Proposed Consent Administrative Order.

FTN Associates, 2014. Appendix I of the Arkansas Water Plan 2015 Update Report http://arkansaswaterplan.org/plan/ArkansasWaterPlan/2014AWPWaterPlan/App%20I_2014%2011%2019%20Physical%20Description%20of%20State.pdf

Clean Harbors El Dorado, 2015a. Letter sent by Kathy Shoemaker (Senior Compliance Manager CHED) to Kyle Barber (Enforcement Analyst, Water Division) Transmittal of the Scoping Plan.

Leppert Associates, 2008. Site Subsurface Remediation System Up-Grade Clean Harbors Environmental Services El Dorado Facility. Power Point Presentation delivered to the ADEQ in Little Rock Arkansas. October 27th, 2008.

Leppert Associates, 2012. Toxicity Reduction Evaluation Report for Outfall 009. NPDES Permit No. AR0037800 Clean Harbors El Dorado, LLC.

Leppert Associates, 2016a. 2015 Annual Report for the Effectiveness of Corrective Measures and Groundwater Monitoring Programs, for Clean Harbors El Dorado, LLC.

Leppert Associates, 2016b. Groundwater Flow and Contaminant Fate & Transport Numerical Model Development Description.

Leppert Associates, 2016c. NPDES Outfall 009 Corrective Action Plan.

Figures

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Map.lpk

Figure 1:Site Location Map

Clean HarborsEl Dorado, LLC

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Former Lagoon 4

East Service Road

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French DrainSump

Sanitary Sewer Line

(Dashed where underground)

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Preserve and Protect

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Limit of Grading

Sanitary Sewer Pipe, Above Ground

Sanitary Sewer Pipe, Below Ground

Oil Pipeline, Below Ground

Flow Line

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Former Concrete Structure

Structure

Catwalk

Fence

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Centerline Alignment

Offset Alignment

Extension Line

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Figure 3:

Lined Channel Contained

Flow East Conveyance 100 cfs

Engineered Design

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El Dorado, LLC

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Typical Ditch Cross Section

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Attachment A: Inspection Form

Inspector Name: Date:

Defect Location, Size, Repair Comments

and Severity (When/How Completed)

Width Descriptions:

Fine: less than 1.0mm

Medium: between 1 to 2 mm

Wide: over 2 mm

Crack Type:

Direction, pattern, etc

Upwelling or

Subsidence >2"

Dip or rise in the pavement surface.

Pressure Damage Damage (spalling, crushing, upheaval).

Accumulation of

precipitation on

concrete ditch

surface

Persistent pools of water, snow, and ice on

pavement surface.

Burrowing Animals Is there evidence of burrowing animals that

may be damaging erosion control

measures/vegetation or the concrete/HDPE

ditch lining.

Patching Note new placement of additional material

on surface of existing concrete, or new

concrete since last inspection.

Cracks

Surface

Deterioration

Disintegration or loss of concrete,

including scaling and abrasion. Note

damage of Fabriform fabric.

East Conveyance Ditch Maintenance ChecklistClean Harbors El Dorado, LLC

Item Description Present?

Inspect the East Conveyance Ditch 50 feet width on either side of the ditch starting 20 feet west of the East Service Road and continue eastward 20 feet past the end of the lined

ditch. Also observe the transition of the east end of the ditch at the weir out toward the Boggy Creek embankment.

Additional Comments:

Groundwater Seeps Groundwater noted by color, typically

brown; persistent standing water over time;

changes in vegetation, deep surface

depression.

Spalling Break up or disintegration of concrete at

seams.

Erosion and Scour

Adjacent to the

Lined Ditch

Has bare soil been exposed, rip rap

displaced, erosion control mat (if present)

torn, is vegetation damaged.

Other

Change in ditch

performance

Accumulation of sediment, vegetation

growth in ditch, new/unusual location of

turbulent water flow.

Pumping/Ditch

Shoulder

Disintegration

Ejection of fine soils through cracks, joints,

or edges.

Evidence of Spills or

Leaks

Pool or stream of fluid accumulating above

or coming from below pavement surface.

1/26/2017 1 of 1 CapInspect1SA2015

CHED Outfall 009 Corrective Action Plan Page 60 Revised January 2017

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minimal as the elevation of Boggy Creek controls the elevation of local groundwater with greater variations in the groundwater elevation seen further west. In other words, the proposed ditch fill design is matched to the variability in the anticipated fluctuation in groundwater elevation. The approach to the Weir is currently a concrete pad and this pad is the future subgrade for the proposed HDPE and concrete ditch lining. The extent of fill in plan view is shown on Figure 38: Lined Channel Grading Plan Schematic. In the Figure, fill is shown as blue and cut is shown in red. Some cut was necessary in specific locations to widen the current shoulders of the ditch in the section of the ditch approaching the Outfall 009 Weir. The maximum fill increase in the vicinity of the double culverts is 5.2 feet while the maximum cut is 2.4 feet near the Weir. The average fill increase for the overall area is 0.83 feet within the limits of grading which is a 26,074 square foot area. A maintenance plan has been prepared to ensure that the East Conveyance Ditch is properly maintained. The goal of the maintenance plan is to monitor the East Conveyance Ditch and surrounding area for groundwater seeps in addition to maintaining the integrity of the concrete lining. The ditch and surrounding area will be inspected after significant rain events or monthly during dry periods. A significant rain event is characterized by two (2) inches or more of rainfall in a twenty-four (24) hour period. An onsite rain gauge will be checked daily for these criteria. If there has been no rainfall within a calendar month following the prior inspection then the facility will conduct the survey at least once monthly for those dry months. Inspections will occur within 48 hours of rainfall cessation. Some waiting time is essential after a storm to allow for local drainage to be complete enough to be able to see the surface of the soil for inspection purposes. This is especially important in looking for scoured areas and seeps. Inspections will focus on the East Conveyance Ditch starting at the East Service Road and continue eastward to the end of the lined ditch and will also include observing the transition of the east end of the ditch out toward the Boggy Creek embankment. The Ditch is to be visually inspected and repairs made as needed. The maintenance plan is found in Appendix E: East Conveyance Ditch Maintenance Plan.

3.4 NPDES Permit Path Forward

The following changes may be considered post-remediation of the East Conveyance Drainage for the area currently served by Outfall 009.

The 2016 NPDES Permitted Outfall 009 (ADEQ 2016c) was issued to discharge water derived from:

(1) Stormwater Runoff (from process areas and the south side of the property); (2) Non-Contact Cooling Water; (3) Cooling Tower Blowdown; and (4) Boiler Blowdown.


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Discharge from the Waste Water Treatment Plant (WWTP) was reduced in October of 2010 by eliminating the hydrocarbon remediation system (primary) treatment train (ADEQ 2010). Discharge for the Cooling Tower Blow Down and Non-Contact Cooling Water ceased years earlier due to modifications in facility operations. The package boiler blowdown either evaporates or goes to the cooling tower but does not go to either Retention Areas 7 or 10. Treatment of stormwater in the WWTP from Retention Areas 7 and 10 continues. With the implementation of the proposed items described in the following sections including a proposal to route treated water to a new Outfall (potential Outfall 010), the last remaining contribution of water flowing over the Outfall 009 Weir will be derived entirely from stormwater runoff from offsite upgradient sources and from the site. Although not specifically included in the NPDES permit, seeps into the East Conveyance ditch currently contribute approximately 3.7 million gallons of groundwater per year as base flow passing Outfall 009. Once the base-flow in the East Conveyance is eliminated through the implementation of the Lined Channel Corrective Action Up-Grade, water flowing over the weir will no-longer be continuous. During and immediately after local storm events, storm water will discharge to Boggy Creek (within the property boundaries). Once the Corrective Action Up-Grade has been completed, storm water discharging at Outfall 009 could be classified as Industrial Stormwater.

In summary, CHED proposes to eliminate NPDES Outfall 009 by: 1.) Request separation within the NPDES Permit for water discharged from the WWTP and stormwater discharged at Outfall 009; 2.) Propose permitting and monitoring of potential Outfall 010 which would be a piped discharge directly from the WWTP with a proposed outfall in an alternate location, likely upstream of the Outfall 009 Weir; and 3.) Propose permitted storm water discharge from the Southern Area under a State of Arkansas Industrial Stormwater General Permit (potential Outfall 011). Additionally, 4.) Add monitoring of stormwater flowing onto the Site at the western property boundary for Lead (at a minimum) to document and compare the occurrence Lead concentrations exceeding the Outfall 009 discharge limit as seen in the Seep No. 11 (On-Flow) sample during the Outfall, Seep, and Storm Water Investigation conducted in April 2015, see Section 3.3.1.1: Contribution from Off-Site Storm Water for details.

3.4.1 SHORT-TERM MONITORING AT OUTFALL 009

Upon the completion of the Corrective Action Up-Grade, CHED proposes to conduct a Short-Term Monitoring program at Outfall 009 to demonstrate the success of the Up-Grade. The need for a Short-Term Monitoring program was identified during the September 18, 2015 meeting between the ADEQ and CHED as a means to verify that the Corrective Action Up-Grade improved water quality at the Outfall 009 weir and a requirement for ADEQ to consider permitting stormwater discharge under a State of Arkansas Industrial Stormwater General


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Permit. The Short-Term Monitoring plan was also documented as a Post-Plan Activity in Section 3.0: Post Conceptual Plan Activities of Attachment A: Scoping Plan (CHED, 2015a) that was submitted to and approved by the ADEQ in a letter dated January 7, 2016 (ADEQ, 2016a). The Short-Term Monitoring program is proposed with the following general guidelines:

• Would begin at the start of the next scheduled quarterly monitoring period under the October 1, 2016 NPDES Permit upon completion of Corrective Action Up-Grades.

• The sampling program would follow exactly the list of constituents and sample collection timing prescribed in the October 1, 2016 NPDES permit. The concentration of Lead in surface water on-flow from the western site boundary should also be monitored concurrent with sampling for Lead at Outfall 009.

• Short-Term Monitoring would conclude upon completion of three (3) full quarters of monitoring with analytical results meeting the requirements and limits Summarized in Section A, Effluent Limitations and Monitoring Requirements, of the October 1, 2016 NPDES permit for Outfall 009.

• At the conclusion of three quarters, with passing results, CHED would have fulfilled the requirements of the Short-Term Monitoring period.

With successful completion of the Short-Term Monitoring period, CHED would pursue the plan of action described in Section 3.4: NPDES Permit Path Forward above, to seek separate water discharge permits for water discharged from the WWTP and storm water passing through the Southern Area.

3.4.2 POTENTIAL NPDES PERMITTED OUTFALL 010

As described in Section 3.4, above, sources of water potentially affected by site operations can be segregated from stormwater derived from the Southern portion of the site where active operations do not occur. As noted in the Introduction section of Attachment A: Scoping Plan (CHED, 2015a) that was submitted to and approved by the ADEQ in a letter dated January 7, 2016 (ADEQ, 2016a), CHED proposes to eliminate Outfall 009 and add a new NPDES outfall for the discharge of treated water from the WWTP. Discharge from the WWTP would likely be piped to a discharge location near Boggy Creek. This piped water would be discharged independently from stormwater from off-Site areas which pass through the Site and storm water accumulating in the Southern portion of the Site. The piped waste water treatment plant outfall will require a separate and dedicated flow monitoring system and sampling point. These devices would be constructed prior to (upstream of) the storm water discharge from the Southern Area. With approval from the ADEQ, potential Outfall 010 will be monitored per the requirements established in a new NPDES Permit.


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3.4.3 POTENTIAL STATE OF ARKANSAS STORM WATER PERMIT OUTFALL 011

Considering a proposal to separate WWTP discharge from stormwater flow and once the groundwater seeps have been eliminated, the only type of permitted discharge remaining for Outfall 009 would be event-based discharge from stormwater runoff derived from the Southern Portion of the Site and upstream-offsite areas. Once the Corrective Action Up-Grade proposed for the East Conveyance is completed and the proposed NPDES Outfall (potentially piped Outfall 010) is constructed, only storm water runoff from non-permitted areas would pass through what is now the Outfall 009 weir. This solution was first proposed in the Introduction section of Attachment A: Scoping Plan (CHED, 2015a) that was submitted to the ADEQ on October 14, 2015. CHED anticipates that it would be most efficient to monitor this event stormwater runoff under Industrial Stormwater General Permit (IGP) ARR000000. To accomplish the proposed change, a new Outfall (potentially Outfall 011) would be designated at the Outfall 009 weir for stormwater accumulated in the catchment basin. Annual monitoring of Chemical Oxygen Demand; Total Suspended Solids; Oil & Grease, pH, will be measured for samples collected at the Outfall under the new IGP. Any additional constituents to be monitored, including Lead, should be monitored both at the western boundary on-flow location as well as at the Weir. Results from laboratory testing and other required information will be compiled in a Storm Water Annual Report and kept on Site with the Storm Water Pollution Prevention Plan records for review upon request.

3.5 Mercury

Clean Harbors has investigated the source of the mercury contamination at Outfall 007. The source was attributed to poor housekeeping managing carbon at the incinerator baghouse collection bins. As part of the air pollution control system, the baghouse bins are the removal system for mercury. The spent carbon contains mercury. In order to control future contamination from this source, Clean Harbors has implemented an increased focus on housekeeping. The housekeeping efforts include immediately cleaning incidental spills that occur when connecting or disconnecting the baghouse collection bins, cleaning forklift tires when exiting the baghouse containment area, and a documented inspection program verifying good housekeeping practices continue. With this increased housekeeping effort, the facility has met the permit parameters for the last two sampling events.

3.6 Post-Plan Activities

Post-Plan Activities were described in Section 3.0: Post Conceptual Plan Activities within Attachment A: Scoping Plan (CHED, 2015a) that was submitted to the ADEQ and approved by the ADEQ in a letter dated January 7, 2016 (ADEQ, 2016a). Per the Attachment, Post Corrective Measures activities should include a short term Outfall


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009 water sampling plan. As such, CHED intends to perform the Short-Term Monitoring Plan that has been described in detail in Section 3.4.1: Short-Term Monitoring at Outfall 009, above. If there are no exceedances in stormwater COCs collected from Outfall 009 during the Short-Term Monitoring period, CHED intends to request to modify the NPDES Permit as proposed in Subsection 3.4: NPDES Permit Path Forward.

3.7 Corrective Measures Schedule

A milestone schedule has been prepared for the project and is presented as Figure 39: NPDES Corrective Measures Schedule. This “T=0” schedule depicts two (2) independent paths, ADEQ approval of this CAP and subsequent NPDES final compliance at Outfall 009 and completion of Corrective Action Up-Grades with completion of permit changes as another scheduling path that is dependent on completion of the Up-Grades. Assuming that the ADEQ will respond to this revised CAP within thirty (30) days of receipt of this revision it is feasible that approval of the CAP would occur during the spring of 2017. The date of final compliance, as specified in the CAO dated November 30, 2016, shall occur no later than one (1) year after the date of ADEQ approval of the CAP. Mobilization and construction of NPDES corrective measures is currently planned to begin in the first quarter of 2017. CHED understands that the ADEQ has approved (ADEQ 2009) the proposed East Conveyance Corrective Action Up-Grade described in the letter from CHED to the ADEQ (CHED 2009). This understanding is verified in ADEQ’s approval of the 2012 TRE (Leppert Associates 2012); therefore, the start of construction is independent of the ADEQ approval of this CAP. Construction is anticipated to be completed within six (6) months of the mobilization date. Upon full implementation of Corrective Measures Up-Grades, CHED intends to perform the Short-Term Monitoring Plan as detailed in Section 3.4.1: Short-Term Monitoring at Outfall 009, above. If there are no exceedances in stormwater COCs collected from Outfall 009 during the monitoring period (3 quarters), CHED will submit a request to modify the NPDES Permit with segregated flow from the WWTP discharging at a proposed pipe (see Section 3.4.2: Potential NPDES Permitted Outfall 010, above for details) and stormwater from the Southern area discharging under an Industrial Stormwater General Permit ARR000000 (see Section 3.4.3: Potential State of Arkansas Storm Water Permit Outfall 011, above for details).

Documents

Mr. Kyle Barber Arkansas Department of Environmental ......Jan 26, 2017 · Dear Mr. Barber, Based on a recent phone conversation with Charles Johnson, Clean Harbors El Dorado, LLC