Table of Contents - Lakewood · Figure 6-5: Scotts Wellfield – Proposed Facilities . Figure 7-1: Hybrid Alternative – Well Location Map . Figure 7-2: Ponders Wellfield – Proposed

Table of Contents

List of Tables .............................................................................................................................. iii

List of Figures............................................................................................................................. iii

List of Appendices ...................................................................................................................... iv

Executive Summary .................................................................................................................... I

Section 1: Background ............................................................................... 1-1

1.1 Authorization and Acknowledgements ............................................... 1-1 1.2 Introduction ....................................................................................... 1-1 1.3 Hydrogeologic Setting ....................................................................... 1-3

Section 2: Existing Equipment and Remaining Life ................................... 2-1

2.1 Water Utility Asset Useful Life ........................................................... 2-1 2.1.1 Wells ...................................................................................... 2-2 2.1.2 Well Pumps ............................................................................ 2-2 2.1.3 Stripping Towers .................................................................... 2-3 2.1.4 Clearwell ................................................................................ 2-3 2.1.5 Booster Pumps....................................................................... 2-4 2.1.6 Chlorination Equipment .......................................................... 2-4 2.1.7 Electrical Gear and Instrumentation ....................................... 2-4

2.2 Findings and Recommendations ....................................................... 2-4

Section 3: PCE Concentrations .................................................................. 3-1

3.1 Historical PCE Concentrations .......................................................... 3-1 3.2 Treated Water PCE Goal .................................................................. 3-2

Section 4: Treatment Alternatives (Task 1) .............................................. 4-1

4.1 PCE Treatment Alternatives .............................................................. 4-1 4.2 Technologies Eliminated from Further Consideration ........................ 4-2

4.2.1 Membrane Degassing Contactors .......................................... 4-2 4.2.2 Venturi Eductor Stripping ....................................................... 4-2 4.2.3 Spray Aeration ....................................................................... 4-3 4.2.4 Vacuum Degasification ........................................................... 4-3 4.2.5 Ozone with Hydrogen Peroxide (Peroxone) ........................... 4-3

4.3 Technologies to be Investigated Further ........................................... 4-3 4.3.1 Granular Activated Carbon (GAC) .......................................... 4-3 4.3.2 Packed Tower Air Stripping (PTA) .......................................... 4-4 4.3.3 ShallowTray™ Aeration .......................................................... 4-5 4.3.4 Multi-Stage Bubble Aeration (MSBA) ..................................... 4-6

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Table of Contents (cont’d)

4.3.5 Advanced Oxidation: UV with Hydrogen Peroxide .................. 4-6 4.4 Treatment Alternative Evaluation ...................................................... 4-8 4.5 Task 1 PCE Treatment Summary .................................................... 4-11

Section 5: Deeper Wells At the Ponders Wellfield (Task 2) ....................... 5-1

5.1 Introduction ....................................................................................... 5-1 5.2 Proposed New Deeper Wells Facilities .............................................. 5-2

5.2.1 Wells ...................................................................................... 5-2 5.2.2 Treatment ............................................................................... 5-2 5.2.3 Chlorine System ..................................................................... 5-3 5.2.4 Facilities ................................................................................. 5-3

5.3 Water Quality .................................................................................... 5-4 5.4 Costs ................................................................................................. 5-4 5.5 Task 2 Summary ............................................................................... 5-5

Section 6: Replacement Wells at New Sites (Task 3) ............................... 6-1

6.1 Introduction ....................................................................................... 6-1 6.2 New Facilities to Replace Wells H-1 and H-2 .................................... 6-3 6.3 Transmission Improvements ............................................................. 6-4 6.4 Costs ................................................................................................. 6-5

6.4.1 Capital Costs .......................................................................... 6-5 6.4.2 Operation and Maintenance Costs ......................................... 6-5 6.4.3 Life Cycle Cost ....................................................................... 6-5

6.5 Well R-1 Site ..................................................................................... 6-5 6.6 120th Street Southwest Site ............................................................... 6-7 6.7 Scotts Wellfield Site .......................................................................... 6-8 6.8 Task 3 Summary ............................................................................... 6-9

Section 7: Hybrid Alternative (Task 4)....................................................... 7-1

7.1 Introduction ....................................................................................... 7-1 7.2 Ponders and 120th Street Southwest Site Combination ..................... 7-2

7.2.1 Ponders Wellfield Facilities .................................................... 7-3 7.2.2 120th Street Southwest Site .................................................... 7-3

7.3 Cost .................................................................................................. 7-4 7.3.1 Capital Costs .......................................................................... 7-4 7.3.2 Operation and Maintenance Costs ......................................... 7-4 7.3.3 Life Cycle Cost and Present Worth Analysis .......................... 7-4

7.4 Task 4 Summary ............................................................................... 7-5

Section 8: Alternatives Comparison and Recommended Alternative ....... 8-1

8.1 Alternative Cost Comparison ............................................................. 8-1 8.2 Alternative Ranking ........................................................................... 8-2

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Table of Contents (cont’d)

8.3 Recommended Alternative ................................................................ 8-2

References ................................................................................................................................... i

List of Tables

Table 2-1: Suggested Water Utility Asset Useful Life Table 3-1: Influent Design Criteria for the Existing Packed Tower Aeration Facility Table 4-1: Comparison of Alternatives Table 4-2: Opinion of Probable Capital Costs Table 4-3: Estimated Annual Operation and Maintenance Costs at 250 MG/Year Production Table 4-4: Estimated Annual Operation and Maintenance Costs at 500 MG/Year Production Table 4-5: Life Cycle Cost for 250 MG per Year Production Table 4-6: PCE Treatment Alternative Ranking Table 5-1: Estimated Annual Operation and Maintenance Cost Table 5-2: Life Cycle Cost for 250 MG/Year Table 6-1: Well R-1 Site Facilities Estimated Annual Operation and Maintenance Cost Table 6-2: Well R-1 Site Facilities Life Cycle Cost for 250 MG/Year Table 6-3: 120th Street Southwest Site Facilities Estimated Annual Operation and

Maintenance Cost Table 6-4: 120th Street Southwest Site Facilities Life Cycle Cost for 250 MG/Year Table 6-5: Scotts Wellfield Site Facilities Estimated Annual Operation and Maintenance

Cost Table 6-6: Scotts Wellfield Site Facilities Life Cycle Cost for 250 MG/Year Table 6-7: Site Comparison Table 7-1: Tasks 1, 2, and 3 Alternatives Summary Table 7-2: Hybrid Alternative Estimated Operation & Maintenance Cost Table 7-3: Hybrid Option Life Cycle Present Worth Table 8-1: Alternative Cost Comparison Table 8-2: Ranking of All Alternatives

List of Figures

Figure 1-1: District Existing Well Location Map Figure 1-2: Ponders Wellfield – Well Location Map Figure 3-1: H-1 & H-2 PCE Concentration Figure 4-1: Ponders Wellfield – Proposed Layout of Well H-3

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Table of Contents (cont'd)

Figure 5-1: Ponders Wellfield New Deep Wells – Proposed Layout Figure 6-1: New Sites Considered / Well Location Map Figure 6-2: Selected Sites – Well Location Map Figure 6-3: Well R-1 Site – Proposed Facilities Figure 6-4: 120th Street Southwest Site – Proposed Facilities Figure 6-5: Scotts Wellfield – Proposed Facilities Figure 7-1: Hybrid Alternative – Well Location Map Figure 7-2: Ponders Wellfield – Proposed Layout of Well H-3 Figure 7-3: 120th Street Southwest Site – Proposed Facilities

List of Appendices

A Robinson Noble, Inc. – Technical Memoranda A-1: Technical Memorandum 3, 28 may 2015 A-2: Technical Memorandum 1, 6 May 2015 A-3: Technical Memorandum 2, 28 May 2015

B Capital Cost Tables

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Kennedy/Jenks Consultants Executive Summary

Key elements:

1. The Ponders Wellfield production is an important source of supply for the Lakewood Water District (District). The production will need to be either maintained or replaced in order for the District to continue to meet existing demands.

2. In July 1981, groundwater contamination was discovered in the aquifer that the District’sPonders wells extracts groundwater from. The contamination was traced to a drycleaning business that is no longer in operation.

3. In 1984, the U.S. Environmental Protection Agency (EPA) installed an air strippingfacility at the Ponders Wellfield to remove the tetrachloroethylene (PCE) from thegroundwater. It was initially estimated the groundwater contamination remediationwould be completed in less than 15 years. The latest estimate is that it will take over100 years to clean up the aquifer.

4. The District has participated with groundwater extraction and treatment in part based onthe short-term duration originally estimated by the EPA allowing continued use of thePonders supply capacity.

5. The groundwater treatment strategy using the Ponders Wellfield has proven effective in reducing the contaminant plume at the District’s wells and allowing the District to continue to provide a safe drinking water to the District’s customers.

6. The existing groundwater treatment facilities are at or beyond the typical useful life forsimilar equipment and field observations confirm the facility needs to be replaced soon.

7. Replacement of the well production capacity at alternative locations is feasible but may prove to be difficult and expensive. The potential that treatment for naturally-occurring contaminants will be required and water distribution improvements to convey new production contribute to the high cost of relocation alternatives.

8. Abandonment of District production at the Ponders site would require an alternative groundwater remediation strategy be developed and put in place to clean up the aquifer.

9. The District ratepayers have been paying to maintain and operate a water treatment facility to treat groundwater contamination caused by others. The Department of Ecology (Ecology) has provided funds to assist with the maintenance of the facility.

Key Findings:

1. Least cost, highest rated alternative is to continue with the pump and treat program atthe Ponders Wellfield.

2. The opinion of probable cost is $3,278,000 with an expected level of accuracy of plus50 percent and minus 30 percent. This estimate is presented based on constructioncosts for 2015 and an Engineering News Record (ENR) Construction Cost Index for(Seattle) of 10,389.

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Kennedy/Jenks Consultants Key Recommendations:

1. A new air stripping facility should be constructed at the Ponders Wellfield.

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Kennedy/Jenks Consultants Section 1: Background

1.1 Authorization and Acknowledgements Lakewood Water District (District) authorized Kennedy/Jenks Consultants to prepare the Ponders Wells Treatment Alternatives Evaluation by contract dated 8 April 2015. Hydrogeologic evaluation support was provided by Robinson Noble, Inc. (Robinson Noble), subconsultant to Kennedy/Jenks.

This project was partially funded by a grant from the Washington State Department of Ecology through a grant from the Toxics Cleanup Remedial Action Grant Program – TCPRA-LaWaDI-000.

This project has been funded wholly or in part by the United States Environmental Protection Agency (EPA) under assistance agreement 99083912 to Washington Department of Health (DOH). The contents of this document do not necessarily reflect the views and policies of the EPA, nor does mention of trade names or commercial products constitute endorsement or recommendation for use.

1.2 Introduction The District’s Ponders Wells, referred to as H-1 and H-2, extract groundwater for drinking water from a shallow aquifer (Aquifer A) that is contaminated with tetrachloroethylene (PCE). The source of the contamination was a dry cleaning business located approximately 800 feet northeast of the District’s wells. The Ponders Wells, are large producing water supply wells for the District, and are vital to maintaining reliable service to the District’s customers. The wells were temporarily removed from service in the early 1980s during the remedial investigation and installation of the groundwater treatment system (packed tower air stripping). During this 3-year period, the District’s customers in the surrounding area suffered low water pressures and inadequate fire flow protection.

When the PCE treatment facility began operation, the EPA Record of Decision (1984) considered it an interim treatment facility with a 3-year life to meet the water supply and contamination control objectives until a final remedial action (RA) was completed. The EPA indicated that the facility may be required to operate several additional years if it became part of the RA. A year later, another Record of Decision (EPA 1985) was released indicating that the stripping towers would need to operate for approximately 10 to 12 years. The District has collaborated with the EPA and Ecology to operate and maintain the system since 1984. The District’s participation has been vital to the remediation of the PCE plume. The District, a public water purveyor, inherited the PCE cleanup impacting two of its most important and strategic wells. The operation and maintenance costs for operating the facility, which has been in operation for over 30 years, have been born by the District rate payers, not the responsible parties or the EPA. However, Ecology has contributed $225,000 for maintenance expenses during this time period. The PCE contamination has persisted way beyond the projected cleanup duration under which the District entered into the restoration partnership.

The packed tower air stripping facility has been in operation since 1984 to remove the PCE contamination from the groundwater in Aquifer A. An evaluation of the site cleanup documented in the Fifth Five-Year Review for the Lakewood/Ponders Corner Superfund Site (U.S. Army Corps of Engineers 2012) concluded that treatment to remove PCE and restore the aquifer is

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Kennedy/Jenks Consultants

expected to exceed 100 years. As stated in that report, the air strippers were nearing the end of their useful life in 2012. A significant capital expenditure is necessary for replacement of the Ponders facilities if groundwater production is to continue at the site or if the District’s groundwater supply wells are replaced at alternative uncontaminated sites.

Figure 1-1 shows the southeastern portion of the District’s Water Service, which includes Wells H-1 and H-2 at the Ponders Wellfield. Figure 1-2 shows the Well H-1 and H-2 locations for the Ponders Wellfield.

The current production rate from Well H-1 is 1,200 gallons per minute (gpm) and the current production rate from Well H-2 is 800 gpm. The rated well pump production rates are 1,400 gpm at 325 feet total dynamic head (TDH) for H-1 and 1,100 gpm at 290 feet TDH for H-2. The water rights certificates indicate instantaneous water rights for Well H-1 shall not exceed 2,000 gpm and for Well H-2 shall not exceed 800 gpm. However, the DOH and Ecology treat the entire site as a wellfield and allow extraction at the combined water right. The District would like to utilize its full instantaneous water rights for Wells H-1 and H-2 and produce up to 2,800 gpm. This is a 40 percent increase over the current production rate with both wells operating. The peak instantaneous production rate is the basis used for evaluation of alternative improvements.

The annual volume of water produced by the Ponders wells has averaged of 246 million gallons (MG) since 2004 with a median annual production of 250 MG. The maximum production from these wells during the same period was 304 MG. The water right for the Ponders wells is 3,780 acre-feet per year (1,232 MG per year). Increased extraction to fully utilize the annual water right would require a 400 percent increase in water production at the Ponders Wellfield.

This report was prepared as a screening evaluation of strategies and alternatives for maintaining a reliable groundwater supply for the District. The evaluation provides an opinion of the cost of groundwater treatment and well relocation alternatives to provide a basis for making an informed decision on necessary water supply improvements. The following alternatives were evaluated:

• Task 1 Alternative Treatment Process Evaluation. Task 1 explored and addressed groundwater treatment improvements necessary to continue groundwater extraction at the existing Ponders Wellfield (Wells H-1 and H-2). Hydrogeologic evaluations were prepared in support of this task by Robinson Noble and attached in Appendix A-1.

• Task 2 Assess Drilling Deeper Wells at the Ponders Wellfield. Task 2 explored the feasibility of drilling new wells into a protected aquifer at the existing Ponders Wellfield to maximize the use of the available groundwater rights associated with the Ponders Wellfield and eliminate the need to treat the water supply to remove PCE from the groundwater. Groundwater treatment for iron, manganese, arsenic, and hydrogen sulfide were also considered and assumed present in the protected aquifer. Hydrogeologic evaluations were prepared in support of this task by Robinson Noble and attached in Appendix A-2.

• Task 3 Assess Relocating Replacement Wells at New Sites. Task 3 evaluated potential siting of new wells to avoid treatment for PCE, address groundwater treatment of secondary contaminants, maximize groundwater rights associated with the Ponders

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WELL G-1, G-2WELL G-1, G-2WELL G-1, G-2

WELL H-1,H-2 (Ponders Wells)WELL H-1,H-2 (Ponders Wells)WELL H-1,H-2 (Ponders Wells)

WELL R-1WELL R-1WELL R-1

WELL K-1, K-2WELL K-1, K-2WELL K-1, K-2WELL F-2WELL F-2WELL F-2

WELL A-3WELL A-3WELL A-3

Legend

Well Located in Aquifer A

Well Located in Aquifer C

Well Located in Aquifer E

LWD Boundary

120th Street Southwest Site120th Street Southwest Site120th Street Southwest Site

Wholesale Transmission MainWholesale Transmission MainWholesale Transmission Main

Note: Basemap taken from USGS Steilacoom Quadrangle

District Existing Well Location Map

Figure 1-1

Scale 1” = 3000’

3000’0’

Lakewood Water District: Ponders Well Alternatives Analysis

Pierce County

T 19,20 N/R 2 E

PM: BGC

June 2015

1531-010B

WELL H-1WELL H-1WELL H-1


Inte

rsta

te 5

Inte

rsta

te 5

Inte

rsta

te 5

McC

hord Drive S

outhwest

McC

hord Drive S

outhwest

McC

hord Drive S

outhwest

New

York Avenue S

outhwest

New

York Avenue S

outhwest

New

York Avenue S

outhwest

Note: Imagery taken from ESRI ArcGIS Ponders Wellfield - Well Location Map

Figure 1-2

50’0’

Scale 1” = 50’


Pierce County

T 19,20 N/R 2 E

PM: BGC

June 2015

1531-010B


Wellfield and limit impacts to existing water rights at other sites. Hydrogeologic evaluations were prepared in support of this task by Robinson Noble and attached in Appendix A-3.

• Task 4 Hybrid Option, Combination of Alternatives from Tasks 1, 2, and 3: This task assessed producing water at a reduced flow rate from the existing Ponders Wellfield (with treatment) and transfer of a portion of the Ponders Wellfield water rights to a new location with an aquifer protected from PCE contamination.

1.3 Hydrogeologic Setting The hydrogeologic setting description presented here of the Lakewood area is primarily based on the U.S. Geological Survey (USGS) study of the Clover-Chambers Creek basin (Savoca et al. 2010) and previous investigations by Robinson Noble completed for the District, including construction reports for each of its wells. Previous works describing the geology of the area include Walters and Kimmel (1968) and Borden and Troost (2001).

The USGS conceptual model describes the hydrogeologic layers of the area as being comprised of nine layers of alternating water-bearing (aquifer) and non-water-bearing (confining layers) sediments. There are five aquifers named A-1, A-3, C, E, and G and four confining layers named Confining Unit A-2, B, D and F. The District has wells in Aquifers A-2 (herein referred to as Aquifer A), Aquifer C, Aquifer E, and Aquifer G. The characteristics of these aquifers are as follows.

Aquifer A – The aquifer below Confining Unit A-2 is mainly composed of deposits from the Vashon advance outwash (Qva). In some areas, older, pre-Fraser coarse grained non-glacial (Qpfc) deposits are also included in this unit. The material is usually well-sorted sand or sand and gravel, sometimes with lenses of silt or clay. Locally, the aquifer appears to be confined by the overlying till. The District has several wells that produce water from this system, including Wells G-1/G-2 and Wells H-1/H-2. Historical records and modeling suggest that this aquifer supports large volumes of withdrawal across the region. Aquifer A is exposed at the bottoms of both American and Gravelly Lakes and along Chambers Creek, roughly from confluence with Flett Creek to Chambers Bay. It is otherwise not exposed at the ground surface in the Lakewood area.

Aquifer C – Sometimes also called the sea-level aquifer due its coincident elevation, this system is somewhat less productive than the other aquifers in the Lakewood area. The unit is usually sand and gravel deposits of pre-Olympia age glacial drift, but lower-permeability deposits of silt, clay or till are sometimes encountered. Productive zones in this unit seem to be more areally discontinuous across the region than is the case with Aquifers A or E. The aquifer is 70 to 150 feet thick in most places in the Lakewood area.

Aquifer E – The second major source aquifer used by purveyors after Aquifer A (in terms of withdrawal), Aquifer E is dominated by glacial drift deposits that appear to correlate with the Stuck Glaciation (Walters and Kimmel 1968). It mainly consists of deposits of silt, sand, and gravel. The aquifer is typically highly confined, is often highly productive, and regionally extensive. The unit ranges in thickness from a few tens of feet to over 200 feet. Lakewood Wells F-2, K-1/K-2, and R-1 all produce from this aquifer.



Aquifer G – The deepest unit defined in the USGS effort is the aquifer underlying confining unit F (Aquifer G) and all of the remaining sediments below that aquifer, as previously identified by the 1985 study by Brown and Caldwell (confining unit H and Aquifer I). These units were undifferentiated by the USGS study due to the lack of deep boreholes to define the various layers across the region. In the Lakewood area, however, there is sufficient information to identify Aquifer G as a separate unit from the units below. Walters and Kimmel (1968) defined the Aquifer G deposits as part of the Orting drift, the oldest glaciation defined in the Puget Sound region.

In general, water quality varies both from aquifer to aquifer and from within each aquifer unit. Localized groundwater contamination exists in several locations as a result of human activities and as a result of naturally occurring constituents present in the aquifer. Naturally-occurring contaminants include arsenic, iron, manganese, and hydrogen sulfide. There are locations where high quality groundwater can be extracted and delivered without treatment. Maintaining, protecting and remediating the groundwater resources within the District is critical to the long-term reliability of the water supply and meeting the community water supply needs.


Kennedy/Jenks Consultants Section 2: Existing Equipment and Remaining Life

2.1 Water Utility Asset Useful Life The Record of Decision states the original design life of the groundwater treatment system installed at the Ponders Wellfield was 15 years (EPA 1984). The PCE contamination proved to be a significantly greater problem than originally understood and the current projected duration to clean up the contaminated aquifer is over 100 years. The Ponders treatment facilities and cleanup effort has proven to be effective in containing the contaminant plume while also providing a safe and reliable drinking water supply. However, the treatment system has been operating for over 30 years and continued remediation of the aquifer must address replacement of the groundwater treatment system.

Typical service life cycle durations were investigated to compare to the existing service life of the existing equipment. Table 2-1 provides suggested water utility service lives for various assets applicable to Ponders. This information was used in the assessment of the remaining useful life of the Ponders facilities. The suggested life cycles are averages based on performance of equipment at other locations. The actual asset useful life can vary depending on a number of factors including environmental conditions and regular maintenance. The following sources were used in developing Table 2-1:

• Useful lives of utility assets developed by the California State Controller’s Office (1976) for use in conducting financial evaluations.

• Washington Utilities and Transportation Commission Typical Average Service Lives, Salvage Rates, and Depreciation Rates for Water Utilities.

• Taking Stock of Your Water System, a Simple Asset Inventory for Very Small Drinking Water Systems (US EPA, 2004).

Table 2-1: Suggested Water Utility Asset Useful Life

Item Suggested Asset Life

(Years) Wells 25-30

Pumping Equipment 20-25 Pumping Plant Structures and Improvements 35-40

Water Treatment Equipment 20-30 Water Treatment Plant Structures 35

Disinfection Equipment 5 Water Mains 12-inch and larger 100

Water Mains 8- to 10-inch 75 Computer Equipment/Software 5

Transformers/Switchgear/Wiring 20 Motor Controls/Variable Frequency Drives 10

Instrumentation Sensors 7



Based on the apparent existing conditions at the Ponders Wellfield, the equipment has performed well and is generally following the average suggested performance life cycle. One exception is the well casing continues to provide reliable service beyond the suggested 30-year useful life.

The following sections provide a more detailed discussion of each asset.

2.1.1 Wells Wells H-1 and H-2 have been in service for 64 years and 56 years, respectively and exceed the average life cycle documented in Table 2-1. Determination of a specific well’s useful life requires a combination of video inspection and knowledge of the existing construction. Additionally, a comparison of the performance of similar local facilities provides an indication of the structural condition of the belowground casing. Local water quality can influence the useful life of a well through corrosion of the well casing and incrustation of the well screen.

Robinson Noble has reviewed a 2003 videotape made when the Well H-2 pump was removed and replaced. The 12-year old videotape indicated the Everdur bronze alloy well screen appeared to be in good condition at that time. However, Everdur screens tend to degrade over time in typical Western Washington groundwater conditions. The videotape also indicated the well casing had experienced relatively heavy incrustations and iron bacteria on the interior. No videotapes associated with Well H-1 were available for review.

There is some risk in assuming that Wells H-1 and H-2 have experienced similar corrosion, particularly since a videotape is not available for H-1. The H-1 well casing is encased in cement grout from the ground surface to the well screen; whereas, H-2 is encased in a gravel pack to the ground surface. The cement grout around the exterior of the H-1 well casing provides an alkaline environment and some corrosion protection to the exterior of the steel casing.

It is Robinson Noble’s opinion the District should plan to replace one or both of the wells within 10 years (Robinson Noble 2015) (see Appendix A-1). It may be possible to extend the well life by installing a liner when the well casing is penetrated by corrosion. Installation of a liner, however, will reduce the well’s capacity and limits the District’s ability to redevelop the well. If the District chooses to replace the wells, the new replacement wells should be suitably sized to meet the District’s objective of utilizing the full 2,800 gpm instantaneous water right.

2.1.2 Well Pumps Wells H-1 and H-2 are equipped with line shaft turbine pumps, which replaced the original submersible pumps. The Well H-1 pump was installed in 2013 and is a Peerless M12HXB 8-stage pump with a design point of 1,400 gpm at a TDH of 325 feet and a 150 horsepower (hp) motor. The Well H-2 pump was installed in 2003 and is equipped with a Peerless 12 MB 6-stage pump with a design point of 1,100 gpm at 290 feet TDH and a 100 hp motor. The design points were based on the pumps being able to discharge directly into the 404 Pressure Zone and assumed the existing air stripping towers would not be necessary at some point in the future. However, the existing operation continues to discharge into the stripping towers and requires significantly lower head pressure. Both pumps utilize variable frequency drives (VFDs), which allow the pumps to discharge into the stripping towers at a lower discharge head. The VFDs also reduce the starting inrush current to the electrical motors and extend the motor life.



Typical life for vertical turbine pumps in Western Washington is in the range of 20 to 30 years, assuming proper operation and maintenance (O&M) (Doug Davidson 2015). This concurs with the suggested asset life in Table 2-1. Conditions that could reduce the useful life of well pumps include: operation at a point not near the best efficiency point, inadequate net positive suction head resulting in cavitation, vibration, and misalignment (Jones 2006). The original design point for both pumps is near the best efficiency point. However, when operating at 70 percent speed to meet the TDH requirements to pump into the stripping towers, the H-1 pump is operating on the far end of the pump curve away from the best efficiency point. At this point, the pump is subject to increased vibration and cavitation resulting in increased wear and reduced reliability.

In the case of the H-1 pump there is approximately a 20 percent loss of pump efficiency when operating at 70 percent of full speed and pumping to the air stripper. A significant improvement can be obtained by removing five of the eight pump stages from the Well H-1 pump. With suitable O&M and the removal of excess pump stages, the Well H-1 pump should have another 18 to 28 years of service life. With suitable O&M, the Well H-2 pump should have another 8 to 18 years of service life.

2.1.3 Stripping Towers The two air stripping towers are constructed from fiberglass, which is subject to degradation from ultraviolet (UV) light. The District painted the fiberglass in 2009 to provide UV protection. However, the upper shoulder surfaces of the towers are beginning to delaminate and cracks are forming around the anchors. As fiberglass cracks, it opens a path for water to enter the structure and wick along the fiberglass fibers. This causes further delamination of the fiberglass and destroys its structural strength.

The towers were designed and manufactured in 1984. The nameplate information indicates the towers were designed for seismic zone III and a wind speed of 80 miles per hour. The Washington Building Code has undergone a number of updates since the towers were installed. More stringent design criteria are required for current designs.

In the late 1990s, it was determined the tower plastic packing had failed as pieces of plastic were appearing in the strainers of nearby water meters. The packing was replaced in 2000.

The existing stripping towers are nearing the end of their useful life and should be replaced with a suitable alternative PCE treatment method if groundwater production is to be continued from Aquifer A at the Ponders Wellfield.

2.1.4 Clearwell The clearwell is a cylindrical concrete tank located under the Ponders Operations Building floor. The clearwell has a 7,125-gallon design capacity.

Access to the clearwell is via a 22-inch-diameter circular manhole type cast iron cover. The access cover was constructed flush with the floor and allows drainage inside the building to enter the clearwell. Current DOH design standards would require raising the access hatch above floor level. A portable ladder must be provided to access the clearwell as it lacks a permanent ladder or steps. The clearwell is considered a permit-required confined space entry.



The District reports the interior clearwell lining is delaminating and in need of restoration.

2.1.5 Booster Pumps The facility is equipped with three 1,000 gpm 60 hp vertical turbine booster pumps that pump water from the clearwell into the distribution system. The pumps were installed in 1984 and should be considered near the end of their useful life.

2.1.6 Chlorination Equipment The facility was originally equipped with chlorine gas cylinders for disinfection. The District converted the facility to use bulk 12.5 percent sodium hypochlorite and more recently onsite generation of 0.8 percent sodium hypochlorite. The facility is equipped with a 48-pound per day (ppd) Siemens OSEC onsite hypochlorite generation system. The equipment is 5 years old and the District’s experience has been that they get about a 10-year life from onsite hypochlorite generation equipment. The current assumption is that the equipment will provide another 5 years of useful life to the facility.

2.1.7 Electrical Gear and Instrumentation The main distribution panel was installed in 1984. The expected service life for this type of equipment is 30 to 40 years. The existing panel is not designed to current standards, arc flash in particular. Parts availability and reliability will become an increasing concern as the equipment continues to age.

The wells and booster pumps utilize VFDs manufactured by Robicon who has been bought by Siemens. Robicon VFDs are still supported by Siemens. However, the typical useful life of a VFD is in the 15- to 20-year range. Board failures and cold solder cracking become an increasing problem as the VFD ages.

The facility is controlled by a Siemens Simatic TI545 programmable logic controller (PLC). Siemens no longer provides support for this model as it was discontinued within the last 8 to 10 years. Control Technologies Inc. (CTI) manufactures spare modules and the District has spare parts in stock. Cold solder joints in the PLC tend to crack from heat and fail after about 20 years of use. More recent PLCs have greater functionality. The District should plan on replacing the PLC and related equipment.

The District has upgraded their SCADA systems at other sites throughout the distribution system; however, SCADA has not been upgraded at the Ponders Wellfield. A new remote telemetry unit (RTU) and new software is needed at Ponders.

2.2 Findings and Recommendations The existing groundwater treatment plant original design life was 15 years by which time the EPA estimated the PCE contamination of the aquifer would be cleaned up. Actual equipment service live cycle duration indicates most assets at the site are at or beyond their useful life. The current projection is that it will take over 100 years of operation to clean up the aquifer. Therefore renewal and/or replacement of the equipment at this site or another location will be



required several times prior to completion of the cleanup effort. The existing equipment has been maintained well and has reached or exceeded the service age of similar equipment when replacement is necessary to provide reliable service and avoid catastrophic failure and unplanned outages. The existing equipment is at or beyond its reliable useful life and it is recommended the equipment be replaced if treatment at this site is to be continued.


Kennedy/Jenks Consultants Section 3: PCE Concentrations

3.1 Historical PCE Concentrations In 1980 and 1981, the DOH conducted volatile organic compound (VOC) analysis of water samples from a number of sites in the Chambers Creek-Clover Creek Basin. The analysis found Lakewood’s Well H-2 contaminated with the following:

• PCE 18 micrograms per liter (µg/l)

• Trichloroethene (TCE) <10 µg/l

• 1,2 (trans) dichloroethylene 61 µg/l

During a follow up investigation in December 1983, CH2MHill conducted a 10-day pump test on Well H-2. The design criteria for PCE and 1,2 (trans) dichloroethylene was based on the concentrations observed at the 2-day point during the pump test. Subsequently, the TCE levels were measured at 28 µg/l and a more conservative design value was selected. The treated water goals were based on a 10-6 carcinogen risk level based on a lifetime drinking water exposure. Table 3-1 lists the design basis for the existing treatment system.

Table 3-1: Influent Design Criteria for the Existing Packed Tower Aeration Facility

Contaminant Design Concentration

(µg/l) Treated Water Goal

(µg/l) PCE 250 0.8 TCE 40 2.7

1,2 (trans) dichloroethylene 360 27

Subsequently, it was determined cis-1,2-dichloroethene (cis-1,2-DCE) was present rather than 1,2 (trans) dichloroethylene. TCE and cis-1,2-DCE have not been detected in the groundwater at the Ponders wells since 2006 and 2004, respectively.

Figure 3-1 presents a graph of the PCE level in the groundwater pumped at Wells H-1 and H-2 since July 1995. Over this time, the groundwater PCE levels have generally declined at this site to an average of 6.7 µg/l, with a maximum of 27.3 µg/l. The PCE levels have increased at monitoring Well 16A, which is screened in Aquifer A to the northwest of the Ponders wells and much closer to the source of the original contamination. The monitoring well (20B) screened in the overlying till near the original contamination has shown decreasing PCE levels. The data show the gradually increasing levels of PCE at Monitoring Well 16A have not affected the PCE levels in Wells H-1 and H-2.



0

5

10

15

20

25

30

PCE

(ppb

)

H-1 & H-2 PCE Concentration

PCE Concentration

95th Percentile

PCE Concentration Trend

Figure 3-1 For the purposes of this treatment alternatives evaluation, the 95th percentile PCE concentration of 12.1 µg/l was selected for the design raw water PCE concentration.

3.2 Treated Water PCE Goal The current maximum contaminant level (MCL) for PCE is 5 µg/l. The method detection limit (MDL) currently used by Water Management Laboratories in analyzing for PCE is 0.5 µg/l. In March 2010, the EPA determined revision of the drinking water standards for PCE and TCE needed to be considered and that scientific advances allowed for stricter regulations. The EPA is currently re-evaluating the MCL of PCE as part of a planned Carcinogenic Volatile Organic Compounds (cVOC) Rule. It is currently estimated the draft cVOC Rule will be published in 2015 or 2016, with the final rule published 1 to 2 years later. At the 21 April 2015 meeting with the District’s representatives, DOH, and Ecology, it was agreed the PCE treatment objective would be to provide water with a PCE concentration below the currently used MDL. Therefore, the PCE treated water goal was set at 0.4 µg/l. This results in 97 percent PCE removal for an influent PCE concentration of 12.1 µg/l. Further evaluations in this report will be based on a 97 percent (minimum) PCE removal treatment goal.


Kennedy/Jenks Consultants Section 4: Treatment Alternatives (Task 1)

4.1 PCE Treatment Alternatives When the initial PCE regulation was developed, the EPA was required to designate Best Available Technology (BAT) for PCE removal from drinking water. The two BATs that were designated for PCE removal are granular activated carbon (GAC) and packed tower air stripping (PTA).

During the initial scoping of this project, the District requested an evaluation of three primary treatment options for the removal of PCE:

• GAC

• Aeration and Degassing

• Advanced Oxidation.

These three primary treatment options listed above can be further broken down to include a number of alternatives within these primary options. Task 1 conducted an initial screening of the following 10 alternatives:

• GAC

• Aeration and Degassing

- PTA

- ShallowTray™ aeration

- Multi-stage bubble aeration (MSBA)

- Venturi eductor stripping

- Spray aeration

- Vacuum degassing

- Membrane degassing contactors

• Advanced Oxidation

- UV with hydrogen peroxide

- Ozone with hydrogen peroxide.



4.2 Technologies Eliminated from Further Consideration

4.2.1 Membrane Degassing Contactors Membrane degassing contactors were initially included in the group of technologies to be evaluated. Membrane degassing removes PCE across microporous hollow fibers that allow gases to transfer, but prevents water from being transferred. The stripped gas is removed by a vacuum or a carrier gas stream. Vacuums are more typically used to remove gases with high Henry’s Law constants, such as oxygen, carbon dioxide, and radon. The use of a carrier gas (e.g., air) may be more appropriate for PCE removal. This technology is still emerging for PCE removal and multiple units in series may be required to meet the goal of 97 percent PCE removal for this project.

Membrana is the manufacturer of the Liqui-Cel degassing membranes. Their use in municipal applications is handled by Layne (previously known as Layne Christensen). These degassing membranes have been used for removing dissolved oxygen, carbon dioxide, and VOCs such as TCE from water. However, there is very limited experience with PCE removal. A pilot test for removing PCE in Boise for United Water was initially promising with two membrane units in series (Randtke and Horsley 2012). However, it was determined to not be cost effective when a 0.5 µg/l treatment goal was set due to concern that the EPA may lower the MCL (Carr 2015).

Layne was contacted regarding the use of membrane contactors for PCE at Ponders. Layne indicated they did not have enough data on PCE removal to support a determination as to whether membranes would operate in series, or in parallel, or if the treatment goal could be achieved at all. They indicated they would be comfortable if the treated water goal was 4.0 µg/l rather than 0.4 µg/l. Layne declined to provide estimating prices for the project and indicated they would need to conduct a 90-day full scale pilot test onsite for $30,000 to $50,000 before they could determine whether it would work and the number of membranes required.

Layne also indicted the typical membrane warranty is 1 year and their estimated membrane life is 3 to 5 years. Based on this information, membrane degassing was removed from further consideration.

4.2.2 Venturi Eductor Stripping Venturi eductor stripping employs a Venturi injector to educt air into a water stream followed by a degas separator. Mazzei’s GDT Degas Separator is typically used for this process.

The Venturi eductor stripping system uses a centrifugal force to create a vortex that allows the removal of the entrained air and dissolved gases of interest including PCE. However, this process is effective with gases having high Henry’s Law constants such as carbon dioxide and radon and would not be expected to meet the PCE treatment goal of 97 percent removal for this project. Based on this information, the Venturi eductor stripping system was removed from further consideration.



4.2.3 Spray Aeration Spray aeration uses nozzles to form small droplets that release gases, including PCE, as the droplets fall into a reservoir. Spray aeration is usually not considered unless a suitable reservoir already exists at the site.

This technology typically removes less than 50 percent of the PCE unless very small droplets are formed [this requires high pressure drops across the nozzles in excess of 40 pounds per square inch (psi)] and a reservoir with a much larger footprint than what the Ponder well site can provide.

This technology would not be expected to meet the PCE treatment goal of 97 percent for this project and was removed from further evaluation.

4.2.4 Vacuum Degasification Vacuum degasification typically employs a tower containing packing material, in which water flows downward through the packing and a vacuum created by a pump extracts gases including PCE from the water. However, this process is effective with gases having high Henry’s Law constants such as oxygen, carbon dioxide and radon and would not be expected to meet the PCE treatment goal of 97 percent removal for this project. This technology was removed from further evaluation.

4.2.5 Ozone with Hydrogen Peroxide (Peroxone) Ozone with hydrogen peroxide is an advanced oxidation process in which ozone and hydrogen peroxide react to form hydroxyl radicals (OH·) that destroy PCE. Because OH· is not selective for PCE, the ozone and hydrogen peroxide requirements depend on other water quality parameters including dissolved organic carbon and bromine that have demands for both ozone and OH· and thus, effect process economics. A potential concern for ozone-hydrogen peroxide compared with UV-hydrogen peroxide is that bromate (a regulated disinfection byproduct) can form with the former process, but not with the latter. Although the technology has been shown to remove PCE and should be capable of meeting the goal of 97 percent PCE removal for this project, it is less appropriate for this project than other technologies because of the potential for bromate formation.

4.3 Technologies to be Investigated Further The following technologies were identified for additional consideration as being technically and potentially economically viable for the Ponders Wellfield.

4.3.1 Granular Activated Carbon (GAC) GAC technology is designated by the EPA as a BAT for PCE removal. GAC is a highly porous media capable of adsorbing numerous organic contaminants. PCE is removed by adsorption to the media surface as the water flows over the media. For well head treatment, GAC is typically contained in a pressure vessel, called a contactor or adsorber. This technology has been proven effective in PCE removal, and can meet the treatment goal of 97 percent PCE removal.



There are a number of GAC suppliers and GAC contactor suppliers. Costs used for this evaluation have been provided by Calgon Carbon, one of the major GAC vendors.

GAC contactors can be operated in series in a lead-lag mode or in parallel. For this option, it is assumed two GAC trains, each with two GAC contactors, would be operated in a lead-lag mode. The GAC contactors would be located outside on a concrete foundation. Each GAC contactor typically has sampling ports at various depths in the GAC media to allow the operator to track the mass transfer zone.

PCE appearing at the outlet of the lead GAC contactor indicate the GAC media is near exhaustion. At that time, the lead contactor is taken offline and the spent GAC media is replaced with fresh GAC media. The contactor with the new supply of GAC media is returned to service as the lag contactor while the contactor with the older media becomes the lead contactor. Initial estimates indicate the GAC media would need to be changed every 5.5 years with an annual water production rate of 250 MG. Spent GAC can either be disposed of or regenerated offsite for reuse. Calgon Carbon’s nearest GAC regeneration facility is located in Gila, Arizona. It may be less expensive to have the spent GAC media incinerated or disposed of in a landfill.

The contactors must be backwashed each time new GAC media is installed. Contactors are also periodically backwashed (monthly to annually, as needed) to fluff the media bed and minimize head loss. Backwash water can be recovered and blended with the raw well water supply prior to treatment. The settled solids generated during the backwash process can be discharged to a waste solids manhole for removal by a vactor truck.

Cartridge filters are typically installed upstream of the GAC contactors to reduce fine sediment loading and minimize head loss build up. Cartridge filters also require periodic replacement.

Three cartridge filter housings, each containing eight 5-micron cartridge filters, would be installed in a building that also contains the electrical gear and onsite hypochlorite generation equipment.

4.3.2 Packed Tower Air Stripping (PTA) PTA technology is designated by the EPA as a BAT for PCE removal. PTAs are generally described as a tower filled with a proprietary packing material designed with a high surface area. Air is blown through the packing countercurrent to the water flow. As the water flows downward by gravity through the packing, it is broken into small droplets with a high surface area to maximize contact with the air. The volatile PCE is transferred from the liquid phase to the air phase. The District currently employs PTA at the Ponders well site for PCE removal and has consistently removed PCE to non-detection levels and met the treatment goal of 97 percent removal. PTA technology will serve as the basis for comparison of other technologies in this evaluation.

There are a number of PTA suppliers. Costs used for this evaluation have been provided by Layne and Tonka Water.

PCE concentrations at the Ponder well site have decreased over time. Therefore, the two 12-foot-diameter towers can be replaced with one 12-foot-diameter tower. New towers are



available in aluminum or FRP shells. FRP is more prone to UV degradation, so aluminum was used for this cost analysis.

It has been assumed a sump will be located in the base of the tower with piping connections to three new horizontal split case booster pumps. It has also been assumed the pumps will be installed in a building that also contains the electrical gear and onsite hypochlorite generation equipment.

Puget Sound Clean Air Agency does not regulate air emissions from Superfund Sites and sites with a Model Toxics Control Act determination. Sites emitting less than 500 pounds per year of PCE are also exempt (Puget Sound Clean Air Agency Regulation I 2013).

Assuming the Ponders Wellfield 20-year average PCE concentration of 6.67 µg/L is stripped at the current median H-1 and H-2 combined production rate of 250 MG per year, the site would emit 14 pounds of PCE per year. If the Ponders Wellfield produces water at the annual water right of 1,232 MG per year, and the PCE averages 12.1 µg/L for the entire year, the site would emit 124 pounds PCE annually and qualify for the exemption. Therefore, capture of the PCE emission from any of the air stripping alternatives is unnecessary.

PTA and the other air stripping alternatives that were evaluated offer an additional benefit of stripping carbon dioxide from the water and raising the pH. The untreated water from Aquifer A at the Ponders Wellfield has a slightly acidic pH (6.6 median), which is frequently corrosive towards copper plumbing in Western Washington waters. Air stripping raises the pH and reduces copper plumbing corrosion.

The stripping towers tend to get dirty given their close proximity to the freeway. The District needs to rent a lift to power wash the stripping towers every couple years.

4.3.3 ShallowTray™ Aeration ShallowTray™ aeration is categorized as a low profile air stripper. It employs a series of stacked perforated trays, in which water flows downward and horizontally through the trays while air flows counter-currently upward through the trays, removing the PCE from the water. The technology is effective in removing PCE from water and meets the 97 percent removal goal of this project. Low profile air strippers have a number of advantages and disadvantages versus packed tower air strippers (Ahmed, et al. 2014):

Advantages:

• Low profile air strippers are smaller and more compact than PTA. They have a lower height because the water flows horizontally in the trays.

• Low profile air strippers are less susceptible to inorganic fouling than the packing media in PTA.

• Maintenance is easier to perform on low profile air strippers as they have no packing media and can be readily disassembled. It is not necessary for the District to rent a lift to clean a low profile air stripper.



Disadvantages

• Low profile air strippers require significantly higher air flow rates and more power to achieve equivalent treatment objectives.

• Low profile air strippers are most applicable for lower water flow rates, typically less than 1,000 gpm (Crittenden, et al. 2012).

Costs used for this evaluation have been provided by Hydro Quip, the manufacturer of this equipment. Equivalent systems can be provided by other manufacturers.

The ShallowTrayTM units can either be located inside a new treatment building or on a concrete slab outdoors. Hydro Quip indicated in most cases, the units are installed indoors. The units are less susceptible to vandalism inside a building. Hydro Quip recommends providing a 7-foot space on both ends of the ShallowTrayTM units to access the cleaning ports with a high pressure cleaning wand.

Three model 81251 units would be required to treat a peak flow rate of 2,800 gpm and meet the treatment goals. Each unit would be equipped with a skid-mounted 50 hp blower, electrical controls and booster pump.

4.3.4 Multi-Stage Bubble Aeration (MSBA) MSBA utilize diffused air bubbles in a series of horizontal flow-through chambers to contact water under turbulent conditions. PCE is removed from the water as the bubbles rise through the chambers. Although MBSA treatment units employ shallow (3-foot to 4-foot) liquid depths that result in much lower profiles than PTA units, they tend to be cost effective for lower flow rates. The technology is effective in removing PCE from water and can meet the goal of 97 percent PCE removal for this project.

The MSBA tanks are constructed from high-density polyethylene (HDPE) with a stainless steel support structure. Five MSBA tanks should be installed in a building with the electrical equipment, booster pumps, and onsite hypochlorite generation equipment.

Costs used for this evaluation have been provided by Lowry Aeration Systems, a major supplier of this equipment.

4.3.5 Advanced Oxidation: UV with Hydrogen Peroxide UV with hydrogen peroxide is an advanced oxidation process in which UV interacts with hydrogen peroxide to form hydroxyl radicals (OH·) that destroy PCE. Because OH· is not selective for PCE, the UV and hydrogen peroxide requirements depend on other water quality parameters including dissolved organic carbon and UV transmittance. The technology has been shown to remove PCE and capable of meeting the goal of 97 percent PCE removal for this project.

UV lamps used for advanced oxidation are available in either low pressure/high output or medium pressure/high output configurations. The low pressure/high output lamps are less expensive, but a significantly higher number of lamps are required. Fewer medium



pressure/high output lamps are required resulting in lower maintenance requirements; however, they require more power.

There are three major UV vendors:

1. Calgon: Medium pressure, high output

2. Xylem (Wedeco): Low pressure, high output

3. Trojan: Low pressure, high output.

Costs used for this evaluation have been provided by Calgon.

The UV reactors are equipped with sensors to monitor the UV output. UV transmittance, turbidity, and flow meters are required. Automatic wiping systems are frequently provided to remove deposits from the quartz tubes and help maintain the UV dose.

Typical UV equipment life is:

• Lamps: 6,000 hours

• Quartz tube: 10 years

• Ballast: 10 years

• Wiper: 5 years.

Hydrogen peroxide is available in 35 and 50 percent concentrations and is typically stored in high purity aluminum or 304L or 316L stainless steel tanks. Hydrogen peroxide is dosed into the flow stream and mixed with a static mixer 3 to 5 pipe diameters upstream of the UV reactors. An excess concentration of hydrogen peroxide dose is required with approximately 1 milligram per liter (mg/l) converted to the free hydroxyl radical. The excess hydrogen peroxide must be quenched with chlorine (or another quenching agent) prior to discharge into the distribution system. Quenching the excess hydrogen peroxide results in a substantial chlorine demand, and requires a large onsite hypochlorite generation system and additional operating costs.

Hydrogen peroxide is considered a Class 2 Oxidizer and a Corrosive by the International Fire Code with an exempt quantity of 250 gallons. Buildings containing hydrogen peroxide in excess of the exempt amount have a High Hazard Group H-3 Building Occupancy Classification that requires a 1-hour fire rated structure with fire sprinklers, secondary containment, and a standby generator.

Personal protective equipment is required when working with hydrogen peroxide and includes (Anderson 2010):

• Splash-proof chemical goggles

• Neoprene or butyl rubber gloves



• Acid-resistant coveralls

• Rubber boots

• Hard hat.

4.4 Treatment Alternative Evaluation Table 4-1 compares the five treatment technologies that were subject to further evaluation.



Table 4-1: Comparison of Alternatives

Alternative

Typical Percent

PCE Removal

Anticipated Water Quality Footprint

Hydraulic Compatibility

Water Rights Issues Maintenance

Safety Issues

Community Issues

Regulatory Impacts Manufacturer

Building & Equipment

Requirements

Capital Costs

(in $1000)

Annual O&M

Costs (a)

GAC > 97%

• Removes TOC • Media supports

biological removal of Fe & Mn

• Low pH groundwater is more corrosive than current treated water

• 1,225 SF GAC pad

• 615 SF backwash tank

• 810 SF building

Head loss through

contactor None

• Periodic cartridge filter replacement

• Periodic GAC replacement

• Periodic backwashing

• Disposal of backwash solids

• Contactor is a confined space

• GAC removes oxygen from air

• Potential falls while maintaining valves

GAC deliveries

• Disposal of spent GAC

• Calgon Carbon • 3 cartridge filter contactors

• 4 - 12-ft-diameter Model 12 GAC contactors

• 70,000-gallon backwash holding tank

$5,184 $54,600

Packed Tower Aeration > 97%

• Raises pH & reduces corrosivity by stripping CO2

• Raises DO levels, improves palatability

• 780 SF PTA slab • 1,400 SF building

Need to repump None

• Periodic packing disinfection

• Periodic pressure washing

• Blower maintenance

• Booster pump maintenance

• Potential fall while painting FRP tower

• Aluminum tower does not require painting

• Fall potential while cleaning

Visual impact

• Air permit not required

• Layne • Tonka Water

• 1 - 12-ft diameter by 33-ft tall tower with 18,000 CFM blower or 2 - 8-ft-diameter by 32-ft tall towers with 2 - 10,000 CFM blowers

• Booster pumps with VFDs

$3,278 $40,900

ShallowTray Aeration > 97%



• 1,900 SF building

Need to repump None

• Periodic cleaning and disinfection



• Rotating equipment • Potential burns from

blower & hot air piping Minimal


• Hydro Quip • 3 - skid mounted 5' X 12'2" SS air strippers, each with 50 hp, 3,600 CFM blower

• Booster pumps with VFDs on 4'6" X 12'2" skid

$3,812 $59,700

Multi-Stage Bubble Aeration > 97%




Need to repump None

• Periodic cleaning and disinfection



• Rotating equipment • Potential burns from

blower & hot air piping Minimal


• Lowry Aeration Systems

• 5 Lowry Model DB-86 (6'7" X 13'1") air strippers each with a 30 hp, 2,000 CFM centrifugal blower

• Booster pumps with VFDs

$4,377 $55,300

Advanced Oxidation: UV with

Hydrogen Peroxide

> 97%

• Oxidizes Fe & Mn • Increase AOC level &

biological regrowth potential

• Low pH groundwater is more corrosive than current treated water


Head loss through static mixers and

reactor

None

• Lamp replacement • Quartz tube

cleaning • Peroxide pump

maintenance

• Potential mercury release if lamp breaks

• Electrical shock potential

• Need to quench excess peroxide

• Hydrogen peroxide storage & handling

• Class 2 Oxidizer & Corrosive

• Hydrogen peroxide truck deliveries

• Increased salt deliveries

• H2O2 is an oxidizer & corrosive

• H3 Building Occupancy

• Fire sprinklers required

• Standby generator required

• Calgon • Xylem

(Wedeco) • Trojan

• 2 UV reactors • Hydrogen peroxide SS

tank & metering pump • Building required for UV

reactor & H2O2 $5,312 $85,500

Note:

(a) Annual O&M Costs based on water production of 250 MG per year.



Table 4-2 presents the opinion of probable capital costs for the five technologies selected for further evaluation. The opinion was developed as an AACE International Class 5 Estimate with an expected accuracy of plus 50 percent and minus 30 percent. A breakdown of the costs are included in Appendix B. Note each of the options assume a new well (see Figure 4-1) would be constructed on site, due to the age and capacity limitations of the existing wells. For each technology, it is assumed one new well will be installed initially and a second well 10 years later. The following capital costs indicate the increment that is related to meeting the District’s normal production costs and the additional increment required for treatment to remove PCE from the water. The production increment includes the cost of developing a new 24-inch diameter well in Aquifer A, well house, and associated piping including replacing a short section of undersized main connecting the Ponders facility to the distribution system, and a 40 ppd onsite hypochlorite generator.

Table 4-2: Opinion of Probable Capital Costs

Treatment Alternative

Production Capital Cost

Treatment Capital Cost

Total Capital Cost

Cost/gpm Capacity

GAC $1,338,000 $3,846,000 $5,184,000 $1,851 Packed Tower

Aeration $1,338,000 $1,940,000 $3,278,000 $1,171

ShallowTray Aeration

$1,338,000 $2,474,000 $3,812,000 $1,361

Multi-Stage Bubble Aeration

$1,338,000 $3,039,000 $4,377,000 $1,563

Advanced Oxidation: UV

Peroxide

$1,338,000 $3,974,000 $5,312,000 $1,897

Tables 4-3 and 4-4 present the annual O&M Cost assuming the current median Ponders’ production level of 250 MG per year and a doubling of the production rate to 500 MG per year, respectively.

Table 4-3: Estimated Annual Operation and Maintenance Costs at 250 MG/Year Production

Alternative GAC Packed Tower

Aeration ShallowTray

Multi-Stage Bubble

Aeration

Advanced Oxidation

UV Peroxide Power $23,600 $28,000 $45,100 $44,100 $37,100

Materials & Chemicals

$20,000 $2,700 $2,000 $1,800 $35,500

Labor $11,000 $10,200 $12,600 $9,400 $13,000 Total $54,600 $40,900 $59,700 $55,300 $85,500


Figure 4-1

Ponders Wellfield - Proposed Layout of Well H-3 Lakewood Water District: Ponders Well Alternatives Analysis

Pierce County

T 19,20 N/R 2 E

PM: BGC

June 2015

1531-010B

Inte

rsta

te 5

Inte

rsta

te 5

Inte

rsta

te 5

McC

hord Drive S

outhwest

McC

hord Drive S

outhwest

McC

hord Drive S

outhwest

PROPOSED WELL H-3PROPOSED WELL H-3PROPOSED WELL H-3

New

York Avenue S

outhwest

New

York Avenue S

outhwest

New

York Avenue S

outhwest



New

York Avenue S

outhwest

New

York Avenue S

outhwest

New

York Avenue S

outhwest

50’0’

Note: Imagery taken from ESRI ArcGIS Scale 1” = 50’


Table 4-4: Estimated Annual Operation and Maintenance Costs at 500 MG/Year Production

Alternative GAC Packed Tower

Aeration ShallowTray

Multi-Stage Bubble

Aeration

Advanced Oxidation

UV Peroxide Power $45,900 $54,900 $89,000 $87,000 $71,700

Materials & Chemicals

$36,300 $3,300 $2,700 $3,500 $66,900

Labor $12,800 $10,200 $14,400 $10,000 $13,300 Total $95,000 $68,400 $106,100 $100,500 $151,900

The present worth of the alternatives was determined using an interest rate of 3 percent and a return period of 20 years. It is assumed a second 24-inch diameter well will be developed in Aquifer A in 10 years at the Ponders site given the age of the existing wells. It is also assumed the onsite hypochlorite generation system would be replaced after 10 years. The present worth in Table 4-5 is based on an annual production rate of 250 MG from the Ponders wells. The present worth of the PTA is significantly less than the other alternatives.

Table 4-5: Life Cycle Cost for 250 MG per Year Production

Alternative GAC Packed Tower Air Stripping ShallowTray

Multi-Stage Bubble

Aeration

Advanced Oxidation

UV Peroxide Capital Cost $5,184,000 $3,278,000 $3,812,000 $4,377,000 $5,312,000 Annual Cost

Present Worth $812,000 $609,000 $888,000 $823,000 $1,272,000

Future Facilities $529,000 $529,000 $529,000 $529,000 $1,266,000 Present Worth $6,525,000 $4,416,000 $5,229,000 $5,729,000 $7,850,000

4.5 Task 1 PCE Treatment Summary The Ponders Wells Treatment Alternatives Evaluation requires comparative rating and ranking of disparate alternatives. Therefore, to select the best solution for the complex challenges presented by the Ponders Wells contamination, a multi-step process was employed to:

1. Identify criteria against which each alternative would be evaluated against

2. Establish the relative importance (weighting) of each criterion

3. Assign a rating or value for each criterion for each alternative

4. Summing the ratings to determine the highest ranked (best) solution.

These four steps for evaluating the alternative solutions were followed in consultation with District staff. The first step was to identify the individual criterion that would be used to evaluate each solution. This resulted in nine criteria being selected as the basis for comparing each solution:



1. Water quality

2. Footprint of the improvements

3. Water reliability

4. Maintenance requirements

5. Operational complexity and safety

6. Community issues

7. Regulatory impacts

8. Implementation duration

9. Costs.

The second step in developing an evaluation system was to determine the relative importance of each criterion. It was agreed the scoring/rating system would be based on a possible total points of 100. In other words, a perfect solution would score 100 points. The possible 100 points was distributed and assigned between costs (40 points); the remaining criteria assigned 60 points.

Within each criterion there often were sub-criterion. The importance of each of these sub-criterion was assessed and a numerical value assigned. For example, one criterion was community impacts. It was assigned an overall importance of 5 (out of 100). In addition, the community impacts criterion was further broken down into three sub-criterion that split the 5 possible points – 1 point – 1 point – and 3 points (see discussion below for more details).

The third step in the evaluation process was to rate each alternative solution against each criterion based on factors described in the following paragraphs.

This rating system is introduced in the Section 4 discussion of treatment alternatives and applied to all alternative solutions in Section 8.

Water Quality (10-point weighting):

• Ability to meet current and future water quality standards (7.5-point weighting): The current PCE MCL is 5 µg/L. The current standard is under review as part of the cVOC Rule and may be lowered in the future, requiring a higher level of treatment. Options that could provide a higher level of treatment or handle spikes in PCE contamination levels with little or no modification were ranked the highest.

• Anticipated water quality (2.5-point weighting): This item considers the other water quality impacts of an alternative. Options that improve treated water quality are ranked the highest. Considerations include the following:

- Ability of a treatment process, such as aeration, to elevate the pH to help meet the Lead and Copper Rule



- The potential need for an additional treatment process, such as use of a source that may require treatment to remove iron and manganese

- The ability of a process, such as GAC, to remove natural organic matter

- A process, such as UV/peroxide, to form assimilable organic carbon (AOC), that could lead to bacterial regrowth in the distribution system.

Footprint (5-point weighting)

• Ability to fit on the current site or a new site (2.5-point weighting): This includes consideration of facilities footprint and whether the wells would have an adequate set back to comply with sanitary setback requirements. Alternatives that satisfy these criteria are ranked the highest.

• Need to acquire additional property or an easement (2.5-point weighting): Sites currently owned by the District that are suitable for the wells and/or treatment facilities are ranked the highest. Sites that are likely to be difficult to acquire or sites that would locate facilities on easements such as schools or park property are ranked the lowest.

Water Reliability (10-point weighting)

• Water reliability considered the ability of an option to provide the full instantaneous water right of 2,800 gpm and whether a new well was likely to produce a sufficient volume to make it worth the cost of development.

Maintenance Requirements (5-point weighting)

• The maintenance criterion considered the labor effort to operate and maintain a facility. For example, GAC was ranked lower due to increased sampling requirements and periodic media change out. Advanced oxidation (UV/Peroxide) was also ranked lower due to the need for regular UVT monitor calibration, lamp replacement, hydrogen peroxide handling, and increased salt deliveries due to higher chlorine demand.

Operational Complexity and Safety Issues (5-point weighting)

• Facilities that required operations beyond groundwater pumping and disinfection were rated lower with the most complex process, advanced oxidation, receiving the lowest score. Safety issues included public safety (mercury lamp breakage) and staff safety.

Community Issues (5-point weighting)

• Visual impact (1-point weighting): Tall stripping towers have the greatest visual impact; however, the low emphasis on this issue is due to close proximity to the interstate and limited visibility from residential neighborhoods.

• Noise (1-point weighting): The low weighting on this issue to due to the close proximity of the Ponders site to the interstate.



• Impact on parks, schools, and neighborhoods (3-point weighting): Options that considered well development near or on park or school property or in residential neighborhoods were ranked lower.

Regulatory Impacts (10-point weighting)

• Air permitting (1-point weighting): Alternatives were ranked lower if an air permit had been required.

• Lead and Copper Rule (1-point weighting): Options that result in an elevated pH similar to the existing PTA process or at a new well site likely to have an elevated pH were ranked higher. Alternatives likely to require increased monitoring for lead and copper or potential pH adjustment were ranked lower.

• Building permit complexity (1-point weighting): Alternatives (such as advanced oxidation) that would have a High-Hazard Group H occupancy classification under the Washington Building and Fire Codes were ranked lower.

• Water rights change issues (7-point weighting): Alternatives that required a water rights transfer from the Ponders Wellfield were ranked lower.

Implementation Duration (10-point ranking):

• Alternatives that were considered likely to be the quickest to implement were ranked the highest.

Costs (40-point weighting)

• Capital cost (10-point weighting): The alternative with the lowest capital cost was credited with the full 10 points. More expensive alternatives were given lower scores based on the ratio of the low cost alternative to the other alternative. For example, if an alternative costs twice as much as the lowest cost alternative, it would receive 50 percent of the possible 10 points.

• O&M costs (10-point weighting): The alternative with the lowest operation and maintenance costs was credited with the full 10 points. More expensive alternatives were given lower scores based on the ratio of the lowest O&M cost alternative to the other alternative.

• Projected life cycle costs (10-point weighting): Twenty (20) -year life cycle costs (present worth) were developed assuming a 3 percent interest rate. The alternative with the lowest present worth cost was credited with the full 10 points. More expensive alternatives were given lower scores based on the ratio of the lowest life cycle cost alternative to the other alternative.

• Capital cost per gpm of instantaneous capacity (10-point weighting): The alternative with the lowest capital cost per gpm of production capacity would be given the full 10 points. More expensive alternatives per gpm of production rate were given scores based on the ratio of the lowest cost per gpm alternative to the other alternative.



Table 4-6 presents the alternatives rankings. As indicated in this table, the air stripping alternatives are preferred. Packed Tower Air Stripping and ShallowTray aeration are the highest and second highest ranked, respectively.

Table 4-6: PCE Treatment Alternative Ranking

Weighting GAC PTA

Shallow Tray MSBA

Advanced Oxidation

UV Peroxide Water Quality

Ability to meet current & future standards 7.5 7.5 7 7 7 7.5 Anticipated water quality 2.5 2 2 2 2 2

Footprint Ability to fit on current/new site 2.5 2.5 2.5 2.5 2.5 2.5

Need to acquire additional property/easement 2.5 2.5 2.5 2.5 2.5 2.5 Water Reliability 10 10 10 10 10 10 Maintenance Requirements 5 2 3 3 3 1 Operational Complexity and Safety Issues 5 3 4 3 3 1 Community Issues

Visual impact 1 1 0 1 1 1 Noise 1 1 1 1 1 1 Impact on parks, schools, neighborhoods 3 3 3 3 3 3

Regulatory Impacts Air permitting 1 1 1 1 1 1

Lead & Copper Rule 1 0 1 1 1 0 Building permit complexity 1 1 1 1 1 0 Water rights change issues 7 7 7 7 7 7

Implementation Duration 10 10 10 10 10 9 Costs

Capital Costs 10 6.5 10 8.5 7.5 6 O&M Costs 10 7.5 10 7 7.5 5 Life Cycle Costs 10 7 10 8.5 7.5 5.5 Capital Cost/ gpm Instantaneous Capacity 10 6.5 10 8.5 7.5 6

Total Points 100 81 95 87.5 85 71



Section 5: Deeper Wells At the Ponders Wellfield (Task 2)

5.1 Introduction This section evaluates the potential of drilling deeper wells at the Ponders Wellfield into one of the deeper confined aquifers that is not contaminated by PCE. Treatment for PCE would no longer be required for the public water supply. This option does not address continued remediation of the contaminant plume at the site. Robinson Noble performed an evaluation of constructing deeper wells at the Ponders Wellfield (see Appendix A-2) to address the following:

• Could the existing Ponders Wellfield support one or more wells targeting deeper aquifers?

• What are the expected hydrogeological conditions?

• Are there any water quality issues?

• Are there water rights considerations to be resolved?

Robinson Noble concluded the following:

• Available information suggests PCE has not migrated into the deeper aquifers. With a properly constructed well seal, well(s) drilled in Aquifer E or G should produce water that does not require PCE treatment.

• Of the three deep aquifers, the highest producing wells would likely be from Aquifer E, with an estimated maximum production rate 1,000 gpm per well. The estimated minimum production rate is 500 gpm per well due to uncertainties regarding Aquifer E at this site.

• On the existing Ponders Wellfield site, up to two deep Aquifer E wells could be developed providing an estimated maximum combined production of 2,000 gpm. This would not fully utilize the 2,800 gpm instantaneous water rights for Wells H-1 and H-2.

• There is a 50 percent probability that groundwater from Aquifer E could have concentrations of iron and manganese above the secondary maximum contaminant level (SMCL) or hydrogen sulfide at objectionable levels.

• The District currently has 13 wells that draw from Aquifer E, none of which have a low pH that requires pH adjustment for corrosion control. In some cases, the District’s deeper wells have low concentrations of arsenic, but the detected levels were below the MCL.

• Changes to the existing Wells H-1 and H-2 water rights are not expected if new deeper wells are drilled at the existing Ponders Wellfield. However, any remaining unused water rights not allocated to the new wells would require water rights processing for transfer to another location.



This alternative discontinues treatment of the PCE contaminated water by the District at the Ponders Wellfield. Therefore, EPA and Ecology would need to provide treatment facilities to remove PCE from the contaminated aquifer.

5.2 Proposed New Deeper Wells Facilities The development of new deeper wells at the Ponders Wellfield that could utilize the entire 2,800 gpm water right does not appear to be feasible. The following facilities were included in this alternative to utilize the available water supply that does not require PCE treatment.

• Two wells (H-3 and H-4) drilled at the Ponders Wellfield to a depth of between 500 and 600 feet to withdraw from Aquifer E, each with an anticipated maximum production rate of 1,000 gpm.

• Treatment for removal of iron, manganese, and hydrogen sulfide.

This alternative assumes the existing treatment facilities for PCE removal and the H-1 and H-2 wells are decommissioned. Figure 5-1, attached with this technical memorandum, shows the proposed new Well H-3 and H-4 locations for the Ponders Wellfield. Well H-4 would be located in the new Treatment Building.

5.2.1 Wells Each well would have the screen set between 500 and 600 feet with the pump inlet set at around 300 feet. The top 200 feet of the annual space between the well casing and bore hole would be sealed to prevent vertical migration of water between aquifers. Well H-3 would be drilled first and located northeast of the existing facilities, 75 feet from the northwestern and northeastern property lines. Well H-4 would be located at least 20 feet from Well H1 and 75 feet from the southwestern property line. Variances for setback requirements would be required from Ecology and DOH. The planned 200 feet deep seal would make the variance request stronger and likely to be approved.

The wells would supply the treatment system and provide the required pressure to supply the distribution system. The anticipated wellhead discharge pressure required to supply the system is 65 pounds per square inch (psi). This is based on the current booster pump discharge pressure of around 60 psi plus an additional 5 psi for the pressure filter system, discussed below. Both vertical turbine well pumps would be operated on VFDs to allow for operational flexibility.

5.2.2 Treatment A treatment system is included as part of this alternative evaluation. This is based on the 50 percent probability that groundwater may have iron and manganese concentrations above the MCL and may have hydrogen sulfide, which could cause taste and odor issues.

There are several options for media and pressure filter systems. This evaluation is based on the ATEC Systems Associates (ATEC) pressure filter system, which the District uses at several other well sites. Other forms of treatment such as membrane filtration, ion exchange, or


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conventional flocculation/sedimentation were not considered due to complexity and cost. Chlorination with filtration was selected as a simple, reliable, and cost effective method of treatment for hydrogen sulfide, iron, and manganese removal.

Chemical oxidation in conjunction with granular media filtration would address all three constituents. The treatment process would include the following elements. Chlorine is injected upstream of pressure filters to oxidize the hydrogen sulfide and iron. Chlorine oxidizes manganese after it has been adsorbed on the granular manganese-oxide media. If silica levels in the groundwater are high, it may also be necessary to add potassium permanganate to oxidize manganese.

For a 2,000 gpm design flow rate, ATEC recommends a pressure filter system that includes two banks of filters with each bank having 10 four foot diameter vertical filters for a total of 20 filters. All filters would be supplied by the well pumps and operate in parallel. The filters would be housed in the treatment building.

The granular media pressure filters must be backwashed periodically to remove accumulated iron and manganese solids and maintain filter performance. Backwash cycles would be initiated either based on filter runtime and/or pressure differential. Each filter is backwashed sequentially, one at a time. When one filter is in backwash, the remaining filters continue to produce filtered water and supply the backwash water. ATEC indicated a filter backwash would use 1,750 gallons of water per filter. The backwash water would be collected in a steel or concrete backwash tank located outside the treatment building. It may be desirable to use a polymer to improve settling of the backwash solids if they consist primarily of manganese-oxides with very little iron-oxides. A pump would recycle the decanted settled backwash water back to the head of the filters. The solids would be periodically pumped to filter-bottom dumpsters for dewatering. Two 15-cubic yard dumpsters would be provided. The filtrate drained from the dumpsters would be directed to an infiltration basin.

5.2.3 Chlorine System Chlorine would be used as the chemical oxidant for treatment and to maintain approximately a 1.0 mg/L free chlorine residual in the filtered water entering the distribution system. Onsite generation of sodium hypochlorite is proposed as this is the District’s preferred method of chlorination. Chlorine would be injected upstream of the pressure filters at a target dose of 2 mg/L. For a design flow of 2,000 gpm, a 60-ppd sodium hypochlorite generation system would be provided. The onsite generation system would be housed in the treatment building with the filters and electrical equipment. The chlorine system would include the onsite generator, water softeners, brine tank, sodium hypochlorite storage tank, metering pumps, and salt.

5.2.4 Facilities The treatment building would contain Well H-4, electrical equipment for the well pumps, treatment and chemical facilities.

The District has indicated the existing facilities at the Ponders Wellfield could be taken offline for up to 1 year to accommodate construction of new facilities. Well H-3 could be drilled and tested first without impacting the existing facilities. Water quality data obtained from pumping Well H-3



would be used to verify the need for iron and manganese treatment and used in the facility design. Then, the existing facilities could be decommissioned and demolished to make room for drilling Well H-4 and constructing the new treatment building and yard piping. Site access would still be from the southern end of the site. New fencing would be required to enclose the new facilities. A parking area would still be provided for up to three to four maintenance vehicles.

The local provider of electrical power is Lakeview Power and Light. It is anticipated the existing power requirements are greater than the new power requirements, so no additional power supply upgrades are needed. Standby power would be provided by a portable generator.

The instrumentation and controls system would be designed for unattended, automated operation per the District’s standards. Both local and remote monitoring and control of critical processes, equipment, and valves would be provided.

5.3 Water Quality Introducing Aquifer E water into the distribution system from the Ponders Wellfield requires a source approval from DOH and a blending evaluation. Initial source monitoring includes a complete inorganic analysis along with two sets of field pH, conductivity, and alkalinity analyses. These data would be compared with the treated water currently supplied from Ponders Aquifer A.

Based on discussions with DOH, if the treated water quality is similar and shown to be noncorrosive, then the District could continue monitoring at the reduced sampling rate (30 samples every 3 years) for compliance with the Lead and Copper Rule (LCR). If they are dissimilar, then two rounds of LCR sampling (60 samples per round) would likely be required in the first year of operation. If the sampling data indicates the lead and/or copper concentrations are below the action level, then reduced sampling would be allowed.

5.4 Costs An opinion of present day capital and operation and maintenance costs were developed for these facilities. The capital costs include drilling and completing Wells H-3 and H-4 and decommissioning Wells H1 and H2. It is assumed this work would be done be a well driller hired directly by the District. The cost for these items includes hydrogeological services. Demolition of the existing facilities and constructing the new facilities would be completed by a general contractor under a separate contract with the District. The opinion of probable construction costs is an AACE International Level 5 estimate utilizing costs from similar constructed facilities.

The opinion of probable cost for the deeper wells at the Ponders Wellfield is $7,542,000. This is equivalent to a capital cost of $3,771 per gpm production capacity.

The O&M costs are based on the following:

• An annual production volume of 250 million gallons



• Labor rate of $43/hour

• Salt price of $5.25 per 50-pound bag

• Power provided by Lakeview Light & Power; $45/month base charge and 8.2 cents per kilowatt-hour, plus a 5% utility tax.

Annual operation and maintenance costs (O&M) are summarized in Table 5-1.

Table 5-1: Estimated Annual Operation and Maintenance Cost

Annual Production 250 MG/Year 500 MG/Year Power $36,700 $71,600

Materials & Chemicals $1,300 $2,600 Labor $7,000 $7,000

Solids Disposal $1,500 $3,000 Total Annual O&M Costs $46,500 $84,200

The life cycle costs are presented in Table 5-2 assuming a 3 percent interest rate for a 20-year period. Future costs consist of replacing the onsite hypochlorite generation system in 10 years.

Table 5-2: Life Cycle Cost for 250 MG/Year

Present Worth Capital Cost $7,542,000

O&M Present Worth $692,000 Future Cost $304,000

Life Cycle Present Worth $8,538,000

5.5 Task 2 Summary It is feasible to drill two deep wells on the Ponders Wellfield that could produce from 1,000 to 2,000 gpm without treatment for PCE removal. This would not fully utilize the current water rights for the Ponders Wellfield of 2,800 gpm. Treatment for iron, manganese, and hydrogen sulfide may be required. Treatment facilities would include pressure filters and onsite chlorine generation. The capital costs are estimated to be $7,542,000. Annual operation and maintenance costs would be approximately $46,500 assuming a 250 MG per year production rate.



Section 6: Replacement Wells at New Sites (Task 3)

6.1 Introduction The possibility of developing new wells at sites other than Ponders to replace Wells H-1 and H-2 and utilize all of the 2,800 gpm water rights allocation was evaluated. In doing so, all issues related to treatment for removal of PCE would be eliminated for the District. The responsibility for cleaning up the contaminated aquifer would remain with Ecology and the EPA.

The Robinson Noble evaluation (see Appendix A-3) concluded the following:

• Six potential well sites were initially evaluated. These sites are shown on Figure 6-1. Further evaluation was conducted for three sites based on site size (including setback requirements), water rights considerations, expected aquifer conditions (both quantity and quality), and ease of site access and acquisition. The sites selected for the more detailed evaluation are shown on Figure 6-2.

Two of the sites selected for further evaluation are owned by the District and have existing wells: Scotts Wellfield and Well R-1. The third site selected for further evaluation is an undeveloped property located along 120th Street Southwest and 47th Avenue Southwest.

• The Well R-1 Site could accommodate up to two new wells, each with a maximum capacity of 1,000 gpm. New Well R-2 would be developed in Aquifer A and new Well R-3 would be developed in Aquifer E.

- This site may accommodate one shallow well (Aquifer A) and one deeper well (Aquifer E).

- Production from the two new wells will likely not result in sufficient pumping capacity to fully utilize the Ponders Wellfield 2,800 gpm water right.

- At this site, Aquifer E is expected to produce water that does not require treatment.

• The 120th Street Southwest Site is sufficiently large to support two new wells; Wells W-1 and W-2.

- The site is near the McChord portion of Joint Base Lewis McChord (JBLM). It is assumed Aquifer A may be at risk of contamination. Therefore, it was not evaluated at this time.

- The proposed wells, W-1 and W-2, would be developed in Aquifer E for a maximum capacity 1,000 gpm per well.

- Aquifer C may be present in sufficient extent to improve production or support a third well at this site; however, test drilling would be required to determine the limits and production potential of Aquifer C.

- The completion of two wells will likely not result in sufficient pumping capacity to utilize the full Ponders Wellfield 2,800 gpm water right.





WELL K-1, K-2WELL K-1, K-2WELL K-1, K-2WELL F-2WELL F-2WELL F-2


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- Groundwater treatment should be assumed for iron, manganese, and hydrogen sulfide from the Aquifer E production.

- This site is located on the eastern side of I-5 in an area (Springbrook) that the Comprehensive Water System Plan (2013) identified as having low pressures when the Ponders wells are not operating. Transmission improvements planned to be bid later this year should improve the pressure and fire flow in this area.

• The Scotts Wellfield Site includes existing Wells G-1 and G-2, both of which are developed in Aquifer A.

- The existing water rights for Scotts Wellfield are not fully utilized by Wells G-1 and G-2. , Additional water rights transferrable to the site are identified as the Abitibi water rights. The District purchased the adjacent south property for future wells that could utilize Abitibi water rights with up to four new wells proposed at this location.

- Two of the proposed four wells (G-3 and G-4) would be constructed to replace existing Wells H-1 and H-2. Well G-3 developed in Aquifer E would provide an estimated maximum capacity of 1,000 gpm. Well G-4 developed in Aquifer C would provide an estimated maximum capacity of 500 gpm.

- The remaining two proposed wells (G-5 and G-6) would be constructed to maximize the existing Scotts Wellfield water rights and the Abitibi water rights.

- The Scotts Wellfield would not support the full utilization of the Ponders Wellfield water rights and the full development of the Abitibi water rights.

• Water quality varies both by location and by Aquifer zone.

- Aquifers C and E may require treatment for iron, manganese, and hydrogen sulfide except for the Well R-1 site. Treatment for these constituents is not anticipated for Aquifer A groundwater.

- pH adjustment from wells developed in Aquifer A and C is not anticipated, similar to Aquifer E.

• New wells developed in Aquifers C or E would require a deep surface seal.

• Some of the proposed well locations are less than 100 feet from the nearest property line, which would require a request for variance from the 100-foot sanitary control radius requirements. It is anticipated the request would be successful as long as the well location is no less than 75 feet from the nearest property line and has the proposed deep surface seal.

The process to move the Ponders water rights to one or more new locations will require a water rights change application filed with Ecology. We anticipate Ecology will not process the application directly, and that the cost-reimbursement program will be used in order to have an acceptable turn-around time for the processing. The cost-reimbursement program allows an applicant to pay for the processing of the application using an Ecology-approved contractor. The applicant (District) can either hire a water rights consultant directly or contract with Ecology to engage one. In the former case, the contractor would produce the majority of products needed to process the application and Ecology would finalize it. In the latter case, the applicant contracts with Ecology who then engages the contractor as Ecology’s consultant to complete



the processing. Either approach will work for the Ponders water right change, but the former approach may offer the District more flexibility in decision making.

The change application for the Ponders rights appears straightforward. A pre-application meeting with Ecology is recommended to determine what issues will be faced, level of investigation, and the contracting approach. Then, the consultant will begin processing, producing an investigative report, conducting a site visit, and drafting a report of examination for Ecology to review and approve. Once approved, the report is posted for public comment over a 30-day period. If comments do not prevent moving forward, the report would be finalized followed by a 60-day appeal period. The District should anticipate 3 months for the contracting process, another 9 months for processing, and then the 90-day period for comments/ appeals. From recent experience, a full 2-year period should be allowed for the water rights process to be completed. For budgeting purposes, assume $50,000 will be needed to complete the processing. This should cover the costs for a water rights contractor, Ecology’s costs, and review/oversight by the District’s water rights attorney.

6.2 New Facilities to Replace Wells H-1 and H-2 New facilities at each of the three sites are discussed below. Similar facilities are proposed and described in detail in Section 5.

Items common to the new facilities at each of the three sites are as follows:

• The wells would be equipped with line-shaft vertical turbine pumps and VFDs.

• The well pumps are sized to provide 60 psi at the connection to the distribution system. An additional 5 psi is required for pressure filters, if needed.

• All well equipment would be housed in either a well house or treatment building.

• The opinion of probable cost is based on utilizing ATEC Systems pressure filters if treatment for iron, manganese, and hydrogen sulfide is required.

• Filter backwash would be recycled. Backwash facilities would include a backwash tank to settle the solids and a recycle pump to recover the decanted backwash water. Solids would be dewatered onsite and hauled to the local landfill for disposal.

• Disinfection would be provided by onsite sodium hypochlorite generation.

• Portable generators, currently owned by the District, would provide backup power.

• The instrumentation and controls system would be designed for unattended, automated operation per District standards. Both local and remote monitoring and control of critical processes, equipment, and valves would be provided.

• It is assumed Wells H-1 and H-2 would no longer be used. One well would be decommissioned, and the other well would be used as a monitoring well.



• It is assumed the Ponders Wellfield facilities would be demolished, dismantled, and removed from the site.

6.3 Transmission Improvements Wells H-1 and H-2 are the only wells in the Springbrook area on the eastern side of I-5. Water supplied to the area from water storage reservoirs is limited by the pipelines connecting to the distribution system on western side of I-5. If H-1 and H-2 are abandoned in favor of new wells on the western side of I-5, transmission improvements will be needed to maintain the existing level of service. Transmission improvements associated with the alternative sites in this task are based on the District’s design standards listed in the Comprehensive Water System Plan.

• Water mains are sized for a velocity of less than 5 feet per second under normal, non-emergency conditions.

• Water mains are sized to not exceed a velocity of 8 feet per second during fire flow conditions.

• The District will endeavor to maintain a minimum pressure of 30 psi at the customer’s water meter except during emergency and fire flow events.

• The District will endeavor to not exceed a maximum pressure of 120 psi excluding surge pressures during normal demand periods.

• A minimum pressure of 20 psi will be maintained at all times in the distribution system and at the customer’s meter during fire flow events.

The District’s hydraulic water model was used to evaluate transmission improvements. The District’s hydraulic model is a static model using Innovyze InfoWater software. The model was updated to include the following transmission main improvements.

• A 16-inch transmission main on Pacific Highway from Bridgeport Way to 112th Street SW.

• The recently installed Springbrook Main Upgrade including a 16-inch transmission main from Ponders along McChord Drive to Bridgeport Way, then north to San Francisco Avenue.

• The Seattle Avenue - I-5 Crossing transmission main improvements planned for 2016.

The model was used to evaluate the following conditions:

• Maximum day demand plus fire flow

• Peak hour demand.



6.4 Costs Planning-level cost estimates have been developed for these facilities, including present day capital and O&M costs, and life cycle cost. The basis for these costs is as follows.

6.4.1 Capital Costs • Well drilling and well decommission would be conducted by a well driller contracted

directly with the District.

• Demolition of the existing Ponders Wellfield facilities and construction of new facilities would be completed by a general contractor under a separate contract with the District.

• The opinion of probable construction costs is an AACE International Level 5 estimate utilizing costs from similar constructed facilities.

6.4.2 Operation and Maintenance Costs • O&M costs were developed for the current median annual production volume of 250 MG

and for an increased annual production of 500 MG.

• Labor rate of $43.00 per hour.

• Salt price of $5.25 per 50-pound bag.

• Power is provided by Lakeview Light & Power at the Well R-1 Site and 120th Street Southwest Site; $45.00 per month base charge and 8.2 cents per kilowatt-hour, plus a 5 percent City utility tax.

• Power is provided by Puget Sound Energy (PSE) at the Scotts Wellfield Site;

6.4.3 Life Cycle Cost • Three percent interest rate over 20 years applied to the annual O&M cost.

• Future costs are based on replacing the onsite hypochlorite generator after 10 years of service.

6.5 Well R-1 Site Well R-1 and the new facilities are shown on Figure 6-3. Well R-1 is developed in Aquifer E but does not require treatment for iron, manganese, or hydrogen sulfide. New Well R-2, developed in Aquifer A, would be located south and east of Well R-1 in its own well house. New Well R-3, developed in Aquifer E, would be located south and west of Well R-1 in its own well house. Existing Well R-1 does not require treatment; therefore, it is assumed Well R-3 will not require treatment.



PROPOSEDPROPOSEDWELL R-3WELL R-3

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Figure 6-3

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The existing site access would still be used with site modifications to access the new wells. New yard piping would connect the new wells to the existing distribution system along 112th Street Southwest. Existing asbestos cement (AC) pipe would be abandoned in place. Distribution system improvements included in the opinion of probable cost are:

• 24-inch main: 150 feet (connection to the system at 112th Street SW)

• 16-inch main: 350 feet (along 112th Street SW)

• 12-inch main: 50 feet (at Nyanza Tank).

The existing Well R-1 onsite chlorine generation system would be replaced with a new 60 ppd onsite chlorine generation system to provide disinfection for all three wells.

Power is provided by Lakeview Light & Power. The combined motor horsepower (hp) for the two new wells is 275 hp. Improvements to supply power to the site to accommodate this additional load would include installing a new 500 kVA padmount transformer.

The opinion of probable capital cost is $3,682,000 (see Appendix B for cost detail). The O&M cost for the Well R-1 Site facilities are summarized in Table 6-1. The life cycle costs are presented in Table 6-2.

Table 6-1: Well R-1 Site Facilities Estimated Annual Operation and Maintenance Cost


Materials & Chemicals $700 $1,400 Labor $6,300 $6,300

Solids Disposal $0 $0 Total Annual O&M Costs $38,200 $69,300

The life cycle costs are presented in Table 6-2.

Table 6-2: Well R-1 Site Facilities Life Cycle Cost for 250 MG/Year






6.6 120th Street Southwest Site The proposed facilities at the 120th Street Southwest Site are shown on Figure 6-4. The site is 1.28 acres in size and would need to be purchased by the District.

Both Wells W-1 and W-2 would be developed in Aquifer E. Given the 50 percent probability the groundwater may have iron and manganese concentrations above the secondary MCL and hydrogen sulfide, which could cause taste and odor issues, a treatment system is warranted as part of this site evaluation. Well W-1 would be housed in the Treatment Building, which would also house the pressure filters, new 60 ppd onsite chlorine generation system, and electrical equipment for both wells pumps. Well W-2 would be located west of Well W-1 in its own well house.

Site access would be from 47th Avenue Southwest. New yard piping and piping along 47th Avenue Southwest would be required to connect to the existing distribution system several blocks south of the site. In addition, segments of distribution piping along 47th Avenue SW and 123rd Street SW would be replaced with 12-inch main to Bridgeport Way and Seattle Avenue. Existing AC pipe would be abandoned in place. Distribution improvements included in the opinion of probable cost are:

• 16-inch main: 500 feet

• 12-inch main: 1,500 feet.

Power would be provided by Lakeview Power and Light. Improvements to supply power to the site would include a padmount transformer and connections to the electrical system.

The opinion of probable capital cost is $8,706,000 (see Appendix B for cost detail). The O&M cost for the 120th Street Southwest Site facilities are summarized in Table 6-3. The life cycle costs are presented in Table 6-4.

Table 6-3: 120th Street Southwest Site Facilities Estimated Annual Operation and Maintenance Cost






Note: Imagery taken from ESRI ArcGIS 120th Street Southwest Site - Proposed Facilities

Figure 6-4

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Table 6-4: 120th Street Southwest Site Facilities Life Cycle Cost for 250 MG/Year




6.7 Scotts Wellfield Site The Scotts Wellfield is conveniently located for supplying water to the District’s wholesale customers through the 20-inch Wholesale Transmission Main located on 112th Street South. The proposed facilities at the Scotts Wellfield Site are shown on Figure 6-5. The figure shows the existing wells (G-1 and G-2) and two new Wells (G-3 and G-4). The figure also shows alternative sites for future wells. The southern alternative site is reserved for a future shallow well that could be used to fully utilize the existing Scotts Wellfield water right. The northern alternative site could be used for a deep well (up to 1,000 gpm if developed in Aquifer E) for Abitibi water rights.

Keeping the two alternative well sites in reserve allows for only one more Aquifer E well and precludes another Aquifer A well for Wells H-1 and H-2 replacement. Well G-3 would be developed in Aquifer E with a maximum capacity of 1,000 gpm, and Well G-4 would be developed in Aquifer C with a maximum capacity of 500 gpm. Both wells require treatment. Well G-3 would be housed in the Treatment Building, which would also house the pressure filters and electrical equipment for both well pumps. Well G-4 would be located north of the Treatment Building in its own well house.

The existing site access road would still be used with site modifications to access the new wells. New yard piping would connect the new wells into the existing distribution system along the access road on the western side of the site. A parallel transmission main would be required to connect the new wells to the 16-inch main on Pacific Highway. Transmission improvements needed to fully develop the remaining Scotts Wellfield water rights in addition to the Abitibi water rights are not included in this evaluation. Distribution improvements included in the opinion of probable cost are:


• 12-inch main: 1,050 feet


• Augered and jacked casing: 150 feet.

The existing onsite chlorine generation system would be replaced with a new 100 ppd onsite chlorine generation system to provide disinfection for all four wells.


WELL G-2WELL G-2WELL G-2

PROPOSED WELL G-3PROPOSED WELL G-3PROPOSED WELL G-3




Note: Imagery taken from ESRI ArcGIS Scotts Wellfield Site - Proposed Facilities

Figure 6-5

100’100’100’0’0’0’ 108th Street Southwest108th Street Southwest108th Street Southwest

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Power is provided by PSE. Improvements to supply power to the site to accommodate the additional load from the new facilities would include a new transformer.

The opinion of probable capital cost is $7,579,000 (see Appendix B for cost detail). The O&M cost for the Scotts Wellfield Site facilities are summarized in Table 6-5.

Table 6-5: Scotts Wellfield Site Facilities Estimated Annual Operation and Maintenance Cost





Table 6-6: Scotts Wellfield Site Facilities Life Cycle Cost for 250 MG/Year




6.8 Task 3 Summary Table 6-7 summarizes information to compare the three sites.

Table 6-7: Site Comparison

Site Well

Maximum Capacity

(gpm) Aquifer

Secondary Contaminant

Treatment Likely

Transmission Improvements

Needed

Capital Cost

($1000s)

Annual O&M Cost

($1000s)

Present Worth

($1000s)

Unused Ponders

Water Right (gpm)

Impacts Abitibi Water Rights

Use Well R-1 R-2 1,000 A No Yes $3,682 $38.2 $4,554 800 Yes

R-3 1,000 E No Total 2,000

120th St. SW

W-1 1,000 E Yes Yes $8,706 $46.6 $9,703 800 No W-2 1,000 E Yes Total 2,000

Scotts Wellfield

G-3 1,000 E Yes Yes $7,579 $45.7 $8,598 1,300 Yes G-4 500 C Yes

Total !,500



Individually, none of the three sites evaluated would fully utilize the Ponders Wellfield 2,800 gpm water rights allocation. The Scotts Wellfield Site would only use up to 1,500 gpm of the Ponders water rights. Each of the other two sites, R-1 and the 120th St, Southwest, would use up to 2,000 gpm of the Ponders Wellfield water rights.

Costs to install two new wells at the Well R-1 Site are substantially less than at the other two sites.

Although the 120th Street Southwest Site costs are the highest, this site does not impact Abitibi water rights. The Well R-1 and Scotts Wellfield sites are reserved for new wells to utilize Abitibi water rights. If the Well R-1 and Scotts Wellfield Sites are now used to transfer the Ponders water rights allocation, new well sites/property would need to be acquired to support the District’s plan for the Abitibi water rights. The potential costs for replacement well sites/property to utilize these water rights are not included in this evaluation.

The Scotts Wellfield site is conveniently situated for supplying water to the Wholesale Transmission Main. However, this alternative would need additional transmission capacity to provide the required flow to the Springbrook area.

The 120th Street Southwest Site is located at a good location for supplying the Springbrook area. However, it will required transmission main improvements to replace the Ponders Wellfield and a proposed intertie with JBLM.

The Well R-1 site is the least conveniently located site for supplying the Wholesale Transmission Main and a proposed intertie with JBLM. This alternative would need additional transmission capacity to provide the required flow to the Springbrook area.



Section 7: Hybrid Alternative (Task 4)

7.1 Introduction A combination of the previous alternatives developed in Tasks 1, 2, and 3 were evaluated to support utilizing the full water rights of the Ponders Wellfield (2,800 gpm). The hybrid alternative selected was based on the following criteria:

• Location. Proximity to the greater Springbrook area, future JBLM intertie and the District’s eastern side water storage tanks is necessary. Close proximity would decrease future major transmission pipeline upgrades.

• Avoid impacting the District’s Abitibi water rights program. Any use of District-owned property that is currently targeted for the transfer of Abitibi water rights was eliminated from further evaluation. Alternatives that would impact the Ponders Wellfield’s ability to provide water to Clover Creek during periods of low flow were also eliminated from further evaluation.

• Highest probability of drilling a successful well in Aquifer E. Aquifer E has the greatest likelihood of developing a well that could produce up to 1,000 gpm. The odds of obtaining the desired well production rate in Aquifer E improve to the north of the Ponders Wellfield.

• Lowest life cycle cost. A present worth comparison of capital and O&M costs were used for this determination.

The findings of Task 1 indicate PTA is the best value treatment alternative for construction of a 2,800 gpm facility at the Ponders Wellfield to replace the existing groundwater treatment system. Drilling deeper wells at the Ponders Wellfield (Task 2) and drilling a new well at the 120th Street location (Task 3) are the only other alternatives that avoid impacting the Abitibi water rights. Table 7-1 provides a summary of the alternatives evaluated in Tasks 1, 2, and 3.

Table 7-1: Tasks 1, 2, and 3 Alternatives Summary

Task Alternative

Production Capacity

(gpm) Capital

Cost O&M Cost

Present Worth Location

Impact Abitibi Water Rights

1 – PCE Treatment at Ponders

GAC 2,800 $5,084,000 $54,600 $6,525,000 Good No PTA 2,800 $3,078,000 $40,900 $4,416,000 Good No

ShallowTray 2,800 $3,812,000 $59,700 $5,229,000 Good No MSB A 2,800 $4,377,000 $55,300 $5,729,000 Good No

UV/Peroxide 2,800 $5,312,000 $85,500 $7,850,000 Good No 2 – Deeper

Wells at Ponders

H-3 and H-4 in Aquifer E

1,000 to 2,000

$7,542,000 $46,500 $8,538000 Good No

3 – New Well Sites

Well R-1 Site 2,000 $3,682,000 $38,200 $4,554,000 Poor Yes 120th St SW Site 2,000 $8,706,000 $46,600 $9,703,000 Good No Scotts Wellfield 1,500 $7,579,000 $45,700 $8,598,000 Fair to

Good Yes



Task 1 – Groundwater Treatment System and Cost Evaluation

The Ponders Wellfield was located near the Springbrook area to support the 404 zone transmission backbone, storage reservoirs, and future JBLM intertie. The existing piping is configured to supply Clover Creek during low flow conditions. The Task 1 evaluation assumed that all options would provide the full Wellfield water rights of 2,800 gpm. The Task 1 option with the lowest life cycle cost is packed tower air stripping similar to the existing treatment facility at the site.

Task 2 – Deeper Wells at Ponders Wellfield

Deeper wells at the Ponders Wellfield have the second highest life cycle cost. Deep wells at the Ponder Wellfield are less likely to produce 1,000 gpm (each) from Aquifer E (compared to the 120th Street Southwest Site and the other sites) due to aquifer characteristics. However, new wells at the Ponders Wellfield could easily supplement Clover Creek and would be in a good location for providing water to the Springbrook area. Deeper wells at the Ponder Wellfield would likely require treatment facilities for iron and manganese.

Task 3 – Alternative Well Locations

Completion of new wells at the Well R-1 site has the lowest life cycle cost of the three alternative sites evaluated for Task 3. However, this location impacts the Abitibi water rights in two ways: future wells planned to utilize Abitibi water rights would have to be located elsewhere and groundwater from this location could not supplement Clover Creek during low flow periods. Furthermore, this site is not located near the Springbrook area.

The 120th Street Southwest Site has the highest life cycle cost of the three alternatives evaluated for Task 3. However, it is slightly more cost effective than the Scotts Wellfield Site based on the cost per gpm of new production capacity. It is assumed treatment would be required for iron, manganese, and hydrogen sulfide. It is close to the Springbrook area and does not impact Abitibi water rights. Compared to the Ponders Wellfield, this location is closer to the District’s F, K, and R wellfields, which have deep wells. As such, it is considered more likely that a new well can be successfully completed in Aquifer E at this site than at Ponders.

The Scotts Wellfield Site is a high District priority for construction of wells that utilize Abitibi water rights and was not considered for the Hybrid alternative. The District would only be able to transfer a maximum of 1,500 gpm of the Ponders’ 2,800 gpm water right to this site.

7.2 Ponders and 120th Street Southwest Site Combination After comparing the previously developed alternatives against the key considerations, the hybrid alternative selected consists of the following:

• A 1,800 gpm packed tower air stripping system utilizing wells that draw from Aquifer A at the Ponders Wellfield.

• A new 1,000 gpm well at the 120th Street Southwest Site developed in Aquifer E with treatment to provide a total capacity of 2,800 gpm to fully utilize the Ponders water rights.



This hybrid alternative supports the ability to easily discharge to Clover Creek under low flow conditions and limits the transmission pipeline improvements required to support delivery of the water supply to the Springbrook area. It also provides continued treatment of water from the contaminated aquifer. The location of the two sites is shown on Figure 7-1 (attached).

7.2.1 Ponders Wellfield Facilities A detailed discussion on the PTA process and facilities needed for the Ponders Wellfield is included in the Task 1 evaluation. For this hybrid alternative, the treatment facilities would have a design capacity of 1,800 gpm instead of 2,800 gpm. A single tower would still be provided along with a blower and booster pumps. The pumps, onsite chlorine generation system, and electrical equipment would be housed in a new building.

The hybrid alternative includes a new 24-inch diameter well (H-3) with a target production of 800 to 1,200 gpm from Aquifer A. Both of the existing wells would have their pumps pulled and the interior of the well casings and screens videotaped. Based on these observations, one of the Ponders wells would be rehabilitated and used in conjunction with the new H-3 well.

For the purposes of developing costs, it was assumed existing Well H-1 would be rehabilitated and a new pump installed. The existing Well H-1 pump would be installed in the new Well H-3. Existing Well H-2 would be taken out of service and used as a monitoring well.

Existing Well H-1 would be retrofit with a 16-inch casing liner and screen assembly to reduce the potential of a casing failure resulting in increased sand production and loss of the well. The drawbacks of installing a liner is the likely reduction in well production capacity and reduced ability to redevelop the well in the future since the extra screen and gravel pack would make standard redevelopment techniques largely ineffective.

Installing a liner screen typically results in a 20 to 40 percent reduction in well production. The assumed production rate for the modified Well H-1 is 800 gpm. It may be beneficial to operate this well on a more continuous basis at a reduced flow rate to help control the plume of contaminated groundwater. The District has indicated it may be able to utilize 400 to 450 gpm continuously to meet a base level water demand in the system and use the new H-3 well for peaking. The EPA would need to conduct a capture zone analysis to determine if this would be beneficial. The existing and proposed well locations at the Ponders Wellfield are shown on Figure 7-2 (attached).

7.2.2 120th Street Southwest Site A detailed discussion on the well and treatment facilities needed for the 120th Street Southwest Site are included in the Task 3 evaluation. For this hybrid alternative, the facilities would include only one new 1,000 gpm well drilled in Aquifer E, Well W-1, and the associated treatment and onsite chlorine generation systems for 1,000 gpm. Treatment at the site is for naturally-occurring iron, manganese, and hydrogen sulfide assumed to be present. The well, onsite generation system, pressure filters, and electrical equipment would be located in a building. The proposed well and building are shown on Figure 7-3 (attached).



Legend

Other Potential Sites

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Hybrid Alternative - Well Location Map

Figure 7-1

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Figure 7-2

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Figure 7-3

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The required transmission improvements would be reduced compared to providing 2,000 gpm production capacity at the new site. Transmission improvements consist of 500 feet of 12-inch main to connect to the existing system on 47th Avenue SW.

7.3 Cost Planning-level costs have been developed for these facilities, including present day capital and O&M costs, and life cycle cost. The basis for these costs is as follows.

7.3.1 Capital Costs • Well drilling and well retrofit would be performed by a well driller contracted directly with

the District.

• Demolition of the existing Ponders facilities and construction of new facilities at both sites would be completed by a general contractor under a separate contract with the District.

• The opinion of probable construction costs is an AACE International Level 5 estimate utilizing costs from similar constructed facilities.

The estimated capital cost for the hybrid alternative is $8,008,000 (see Appendix B for cost detail).

7.3.2 Operation and Maintenance Costs • Total annual production (from both sites) volume of 250 MG (current median) to 500 MG

(if production doubles in the future).

• For each annual production scenario, it was assumed the Ponders facilities (Wells H-1 and H-3) would produce 64 percent of the total annual production. This percentage is based on these facilities having a production capacity of 1,800 gpm compared to the instantaneous water right limit of 2,800 gpm. Well W-1 would make up the difference in the annual volume.

• Labor rate of $43.00 per hour.

• Salt price of $5.25 per 50-pound bag.

• Power provided by Lakeview Light & Power for both sites; $45.00 per month base charge and 8.2 cents per kilowatt-hour, plus a 5 percent utility tax.

7.3.3 Life Cycle Cost and Present Worth Analysis • Three percent interest rate over 20 years applied to the annual O&M cost.

• Life cycle cost was determined using a present worth analysis.



Estimated annual O&M and life cycle costs are presented for the combined Ponders Wellfield Facilities and 120th Street Southwest Site Facilities in Table 7-2. Costs are based on an annual production of 160 MG and 320 MG from Ponders and 90 MG and 180 MG from the 120th Street Southwest Site.

Table 7-2: Hybrid Alternative Estimated Operation & Maintenance Cost

Site Item 250 MG/Year 500 MG/Year Ponders Power $18,400 $35,600


120th St. SW Power $8,000 $14,400 Materials & Chemicals $500 $900

Labor $6,500 $6,500 Solids Disposal $400 $400

Total Annual O&M Costs

$44,900 $69,400

The life cycle cost for the Hybrid Option is presented in Table 7.3.

Table 7-3: Hybrid Option Life Cycle Present Worth




7.4 Task 4 Summary The hybrid alternative meets the criteria identified and maximizes the potential to provide 2,800 gpm of instantaneous production capacity under the existing Ponders Wellfield water rights.



Section 8: Alternatives Comparison and Recommended Alternative

8.1 Alternative Cost Comparison Table 8-1 presents a cost comparison of the alternatives assuming an annual production of 250 MG.

Table 8-1: Alternative Cost Comparison

Task Alternative

Production Capacity

(gpm) Capital Cost

O&M Cost

20 Year Life

Cycle Present Worth

Capital Cost

Per gpm Capacity

Life Cycle Cost Per 1,000 gal Produced

1 – PCE Treatment at Ponders

GAC 2,800 $5,184,000 $54,600 $6,525 000 $1,851 $1.31 PTA 2,800 $3,278,000 $40,900 $4,416,000 $1,171 $0.88

ShallowTray 2,800 $3,812,000 $59,700 $5,229,000 $1,361 $1.05 MSBA 2,800 $4,377,000 $55,300 $5,729,000 $1,563 $1.15

UV/Peroxide 2,800 $5,312,000 $85,500 $7,850,000 $1,897 $1.57 2 – Deeper

Wells at Ponders

H-3 and H-4 in Aquifer E

1,000 to 2,000 $7,542,000 $46,500 $8,538,000 $3,771 $1.71

3 – New Well Sites

Well R-1 Site 2,000 $3,682,000 $38,200 $4,554,000 $1,841 $0.91 120th St SW

Site 2,000 $8,706,000 $46,600 $9,703,000 $4,353 $1.94

Scotts Wellfield

1,500 $7,579,000 $45,700 $8,598,000 5,053 $1.72

4 – Hybid PTA at Ponders & Well W-1

2,800 $8,008,000 $44,900 $9,170,000 $3,275 $1.83

The data in Table 8-1 indicate that in general the air stripping alternatives tend to be the most cost effective. Task 1 – PTA alternative is the most cost effective alternative in terms of:

• Present worth

• Capital cost per gallon of production capacity

• Cost per 1,000 gallons produced over a 20-year life cycle.

ShallowTray aeration has the second lowest capital cost and cost per gallon of production capacity of the air stripping alternatives. Relocating the Ponders production capacity to the R-1 site has the second lowest capital cost and cost per 1,000 gallons of water produce of all the alternatives; however, its capital cost per gpm of capacity is higher than all of the air stripping alternatives.



8.2 Alternative Ranking Table 8-2 provides a ranking of the alternatives using cost and non-cost criteria weighting developed in Section 4. The ranking criteria indicate that the Air Stripping Alternative is the preferred alternative. PTA has the highest ranking, with ShallowTray Aeration having the second highest ranking.

Table 8-2: Ranking of All Alternatives

Weighting Task 1 Task 1 Task 2 Task 3 Task 3 Task 3 Task 4

PTA ShallowTray

Deeper Wells R-1 Site

120th St SW

Scotts Wellfield Hybrid

Water Quality Ability to meet current and

future standards 7.5 7 7 7 7.5 7 7.5 7 Anticipated water quality 2.5 2 2 2 2.5 2 2 2 Footprint

Ability to fit on current/new site 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 Need to acquire additional property/easement 2.5 2.5 2.5 2.5 0 0 0 0 Water reliability 10 10 10 5 7 7 5 9 Maintenance requirements 5 3 2.5 4.5 5 4.5 4.5 2 Operational complexity and

safety issues 5 4 3 4 5 4 4 3 Community issues

Visual impact 1 0 1 1 1 1 1 0 Noise 1 1 1 1 1 1 1 1 Impact on parks, schools, neighborhoods 3 3 3 3 3 3 3 3 Regulatory impacts

Air permitting 1 1 1 1 1 1 1 1 Lead & Copper Rule 1 1 1 1 1 1 1 1 Building permit complexity 1 1 1 1 1 1 1 1 Water rights change issues 7 7 7 7 0 0 0 3 Implementation duration 10 10 10 10 7 7 7 7 Capital costs 10 10 8.5 4.5 9 4 4.5 4 O&M costs 10 9.5 6.5 8 10 8 8.5 8.5 Projected life/life cycle costs 10 10 8.5 5 9.5 2.5 2.5 4

Capital cost/gpm instantaneous capacity 10 10 8.5 3 6.5 2.5 2.5 4

Total Points 100 94.5 86.5 73 79.5 59 58.5 63

8.3 Recommended Alternative The recommended option is to continue treatment at the Ponders Wellfield using air stripping. The facility should be designed for 2,800 gpm to fully utilize the District’s instantaneous water right. During the preliminary design a final selection should be made between PTA and ShallowTray Aeration. This option provides the District and the Agencies responsible for cleaning up the contaminated aquifer the following benefits:



• Air stripping is the lowest cost alternative

• Air stripping at Ponders continues to provide treatment of the contaminated aquifer

• This alternative maximizes the District’s water right at an important location in the distribution system.



References

Ahmed, A.T., et al., 2014, Removal of Volatile Organic Contaminants via Low Profile Aeration Technology. Denver, CO. USEPA, Water Environment Research Foundation, and Water Research Foundation.

Anderson, R.A., 2010, Hydrogen peroxide (H2O2) Safe Storage and Handling, TIP 0606-24, Technical Association of the Pulp and Paper Industry.

Borden, R.K., and Troost, K.G., 2001, Late Pleistocene Stratigraphy in the South-central Puget Lowland, Pierce County Washington: Washington Division of Geology and Earth Resources Report of Investigations 33, 34 p. California State Controller’s Office, Accounting Standards & Procedures for Special Districts, 1976, Appendix A Suggested Useful Lives of Fixed Assets.

Carr, W. et.al., 2015, Cleaning Up Someone Else’s Mess: Wellhead Treatment of PCE. Pacific Northwest Section AWWA Annual Conference, Bellevue, WA.

Crittenden, J.C. et al., 2012, Water Treatment Principals and Design, 3rd Ed. John Wiley & Sons, Hoboken, New Jersey.

Davidson, D., 2015, Private communication. PumpTech.

Jones, G.M. et al., 2006, Pumping Station Design. Butterworth-Heinemann. Burlington, MA.

Murray Smith Associates, 2013, Lakewood Water District - Comprehensive Water System Plan

Puget Sound Clean Air Agency, 2013, Regulation I, Article 6 New Source Review.

Randtke, S.J. and Horsley, M.B., 2012, Water Treatment Plant Design, 5th Ed. McGraw Hill.

Robinson and Roberts, 1949, Report to Lakewood Water District on Test Well No. 3 near Ponders Corner: prepared for Lakewood Water District, 4 p. Robinson and Roberts, 1950, Report to Lakewood Water District on Test Well No. 2 at the Scott Location near Lakewiew: prepared for Lakewood Water District, 2 p. Robinson and Roberts, 1950, Construction Report on Well “G,” Scott location: prepared for Lakewood Water District, 6 p. Robinson and Roberts, 1951, Construction Report on Well “H,” Ponders Corner: prepared for Lakewood Water District, 4 p. Robinson and Roberts, 1959, Report to Lakewood Water District on Construction and Testing of Well H-2 at Ponders Corner: prepared for Lakewood Water District, 6 p.

Ponders Well Treatment Alternatives Evaluation, Lakewood Water District References - i w:\2015\1597006.00_lakewood_wd_ponders_eval\alternatives_eval\arp finalponders_report07-28_mdl.doc


Robinson and Roberts, 1960, Report to Lakewood Water District on Construction and Testing of Well G-2 at Scott Location: prepared for Lakewood Water District, 5 p. Robinson and Roberts, 1963, Drilling and Construction of Well E-2 for Lakewood Water District: prepared for Lakewood Water District, 8 p. Robinson and Noble, 1985, Construction report for Well R-1 (Cloverdale Site): prepared for Lakewood Water District, 7 p., appendix. Robinson and Noble, 1996, Lakewood Water District Aquifer Management Plan: prepared for Lakewood Water District, 51 p., 2 appendices. Robinson Noble, 2015, Draft Technical Memorandum 3, Ponders Wellfield Conditions Evaluation, 28 May 2015.

Savoca, M.E., Welch, W.B., Johnson, K.H., Lane, R.C., Clothier, B.G., Fasser, E.T., 2010, Hydrogeologic Framework, Groundwater Movement, and Water Budget in the Chamber-Clover Creek Watershed and vicinity, Pierce County, Washington: Scientific Investigations Report 2010-5055. US Army Corps of Engineers, Seattle District, 2012, Fifth Five-Year Review for the Lakewood/Ponders Corner Superfund Site.

US Environmental Protection Agency, 1984 EPA Superfund Record of Decision: Lakewood, EPA ID: WAD050075662. OU 00.

US Environmental Protection Agency, 1985 EPA Superfund Record of Decision: Lakewood, EPA ID: WAD050075662. OU 01.

US Environmental Protection Agency, 2004, Taking Stock of Your Water System, A simple Asset Inventory for Very Small Drinking Water Systems. Publication 816K03002.

Walters, K., Kimmel, G.E., 1968, Ground-Water Occurrence and Stratigraphy of Unconsolidated Deposits, Central Pierce County, Washington: US Geological Survey Water Supply Bulletin No. 22, 1968.

Washington Utilities and Transportation Commission. Depreciation Schedule Spreadsheet: Typical average Service Lives, Salvage Rates, and Depreciation Rates for Water Utilities.

Well H-1 Water Right Certificate G2-GWC1289, 1951, Lakewood Water District.

Well H-2 Water Right Certificate G2-GWC3831, 1960, Lakewood Water District.

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Appendix A

Robinson Noble, Inc. – Technical Memoranda

A-1: Robinson Noble, Inc. – Technical Memorandum 3, 28 May 2015



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2105 South C Street 17625 130th Avenue NE, Suite 102 Tacoma, Washington 98402 www.robinson-noble.com Woodinville, Washington 98072 P: 253.475.7711 | F: 253.472.5846 P: 425.488.0599 | F: 425.488.2330

Technical Memorandum 1

Lakewood Water District

Ponders Wellfield Alternatives Analysis Date: May 6, 2015 To: Mike Norton, P.E., Kennedy/Jenks Consultants cc: Milt Larson, P.E., Kennedy/Jenks Consultants From: Burt G. Clothier, LHG

Subject: Construction of a new, deep well (H-3) at the Ponders site

New Well Alternative at Ponders

The objective of this task is to evaluate the option of drilling one or both of Wells H-1 and H-2 deeper to access a lower level aquifer. The concept is that by drawing supply from a lower and uncontaminated aquifer, treatment for removal of PCE, which is required from H-1 and H-2, would no longer be required.

Our review of the site finds the existing property can support additional well(s), although an ad-ditional well may require development of additional infrastructure, power, and plumbing. There appears to be enough property available to site up to two additional wells within current bound-aries. In our opinion, there is not enough room for a third new well.

New water wells drilled into deeper zones adjacent to the District’s shallow aquifer Wells H-1 and H-2 will be required, under WAC 173-160, to have a seal placed below the shallow aquifer so that transfer of water from shallow to deeper zones cannot happen. Because this seal will isolate the shallow aquifer from deeper zones, the new well(s) can be placed relatively close (50 feet) to the existing wells, thus less property is required. The requirement for a 100-foot sanitary control radius around a public supply well may also be reduced through mitigation by construction of the aquifer surface seal (that will reach from ground surface to below the shal-low aquifer, approximately 200 feet at this site). To reduce the size of the sanitary control radi-us, a variance will be needed from the Departments of Ecology and Health.

Expected Hydrogeological Conditions

The Ponders Wells site, shown on Figure 1, was first explored in 1949 by the drilling of Test Well 2 to a depth of 510 feet. There were several thin zones that showed low water-bearing potential but only the zone between 96 and 115 feet appeared to be capable of supporting a useable quantity of water. Subsequently, Wells H-1 and H-2 were drilled and completed be-tween the depths of 86 and 107 feet in Aquifer A. Current production from H-1 is about 1,200 gpm and from H-2, 800 gpm. Maximum practical production rates appear to be about 1,400 and 1,100 gpm, respectively.

Aside from the District’s wells, there are few deep wells close to this location that provide us with the hydrogeological information needed to predict, with any certainty, if a deeper well completed in Aquifers C, E, or G would be successful at the Ponders well site. The original test

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well drilling implies that Aquifer C at this site may have a limited production potential. The pro-duction capability from Aquifers E and G at this location are unknown. The District’s Shop and Washington Blvd wells (Wells D-2/D-3 and E-2/E-3, respectively), about one mile to the north-west, produce from both Aquifers C and E. Production rates in these wells range between about 800 and 1,500 gpm.

Two wells were drilled for McChord AFB in 2000 and 2001 to depths of 688 and 1,013 feet re-spectively. They are located about 1.7 miles southeast of the Ponders Well site. Because of the potential for synthetic organic chemical contamination, the wells were required to be drilled past Aquifer A into deeper aquifer zones. The surface seals were extended to depths of 280 feet for each well to eliminate any potential for shallow aquifer water to transfer down to deep-er aquifer zones.

While drilling the first well, Aquifer C was encountered between 300 and 346 feet. A layered aquifer between 422 and 552 feet and a separate zone, also in layers, between 592 and 685 feet were then drilled. These are likely zones of Aquifer E together but might represent Aqui-fers E and G. The first well was completed with three sections of screen placed against the most permeable zones between 593 and 681 feet.

The second well found Aquifer C between 270 and 288 feet, and Aquifer E was found between 528 and 698 feet. Drilling continued and two deeper aquifers were present below Aquifer E, a thin zone of coarse sand and gravel between 815 and 823 feet and a heaving silty sand from 963 to 1,000 feet. Apparent permeability field tests showed that the most permeable aquifer materials found at this site were between 815 and 823 feet, and the well was completed at that depth.

Both McChord wells were capable of producing their design rate of 500 gpm.

Water Quality

Current information suggests that the contamination from PCE in the Aquifer A sediments has not migrated downward to deeper aquifers. If properly constructed, a new well on the site will not represent a significant risk to deeper water resources. From regional information at hand, we expect that deeper aquifers (Aquifers C, E and G) will not have contamination issues.

Water quality concerns from deeper aquifers usually center on elevated concentrations of iron and manganese and from hydrogen sulfide odor. Another concern is correcting for incompatible pH values, as water from some deep aquifers in the region have different pH values than shal-low aquifer waters. Placing deep aquifer water into the water system may require rebalancing the deep water pH prior to mixing with other water sources in the system.

While many deep wells in the region do not exhibit problematic water quality signatures, we nonetheless regard the chances of encountering iron, manganese, or odor issues in deep wells (Aquifers E or G) as about an even split between having concentrations above or below treat-ment levels. A well completed in Aquifer C, if present, may also face the same water quality issues. Based on the District’s previous experience, the chance of having elevated iron or man-ganese is somewhat more likely in an Aquifer C well than the deeper aquifer wells. The District currently has four Aquifer C wells with these issues but only two Aquifer E wells that need sim-ilar treatment. The majority of the problematic sites are on the west side of the three local lakes.

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Occasionally deep wells have other water quality issues stemming from long groundwater resi-dence times. For example, for some deep wells, arsenic may be above the maximum allowed contamination level (MCL). The chance of encountering such an issue at this site is fairly low.

Production Rates

Maximum current production from the Ponders site is about 2,500 gpm (subject to limitations imposed by the treatment facility). Adding a new well to produce water from a deeper aquifer might be needed to replace the shallow production from Wells H-1 and H-2. Based on neighbor-ing wells and limited on-site information, production from Aquifer C, if a productive zone is en-countered in the new well, is not expected to exceed 500 gpm. Production from a well com-pleted in Aquifer E appears to be more likely to be successful, but rates over 1,000 gpm are not expected. For planning purposes, a production range of between 500 gpm and 1,000 gpm in each well is appropriate. The potential from Aquifer G cannot be reliably predicted.

By drilling two wells to the deeper aquifers, it may be possible to yield significantly more pro-duction than a single deep well. Based on our review of other nearby deep wells, the likely yield from a pair of wells will probably be 2,000 gpm or less, though dependent on site-specific con-ditions, a higher total yield may be possible. Thus, while possible, a deeper well or wells on the Ponders site is not expected to fully replace the water produced by the existing wells. In such case, one or more of the Aquifer A wells may still have to operate to exercise the full water right, which would necessitate retention of the treatment plant.

Water Rights Considerations

Replacement of the existing wells or addition of new wells on the Ponders property can occur without a change to the existing water rights under RCW 90.44.100. After completion of a suc-cessful well, the District will need to complete and provide a Showing of Compliance form to document the addition of a new well, or replacement of an existing well, under the existing wa-ter right. Supporting documentation, such as a well construction report, may also be needed. Neither the compliance form nor the supporting information (if needed) are expected to require significant effort to produce.

As noted above, fully exercising of the existing water right from new, deeper wells may not be possible. In which case, either the existing wells will need to produce the remainder of the allo-cated rights or the District could transfer some or all of the remainder to a different site. If a transfer is desired, a water rights change application will need to be submitted and processed. This effort will be more fully discussed in later technical memoranda.

Lastly, a deep well completed in Aquifers E or G could be designated as a withdrawal location for the District’s wholesale water program authorized by its Abitibi water rights transfer com-pleted in 2005. This would also require a water rights change application, but would be sepa-rate from the existing water rights, leaving the site’s existing rights available to support the ex-isting wells or, if moved, to support other new wells elsewhere.

Suggested Well Construction

We recommend construction of a 600- to 800-foot deep production well at this site using cable-tool drilling methods. The use of cable tool equipment, as opposed to using other drilling meth-ods, allows for better soil samples that can be tested for grain size and apparent permeability during drilling. This drilling method also provides us with the ability to test aquifer zones for quality and quantity as they are encountered during drilling. If we observe an aquifer zone with


useable production potential, we can temporarily stop drilling and test the zone, but retain the ability to continue drilling to deeper aquifers if needed. This will be a key consideration as we drill through the Aquifer C sequence. Should Aquifer E not be present or is unsuitable for com-pletion of a well (due to poor water quality or insufficient production capability), then the well can be re-configured to tap the shallower aquifer, if present.

A 600-foot well is anticipated to be completed as an Aquifer E production well. However, if de-sired by the District, this drilling offers an opportunity to accomplish exploration drilling using 12-inch casing. Drilling could proceed to a depth of 800 feet if the District is interested in as-sessing Aquifer G as a possible wholesale source. Using this production well as a starting point for deep exploration is less expensive than drilling a dedicated test well. This deeper drilling could also occur in the instance where Aquifer E is not found or is insufficient to warrant test-ing.

With the above in mind, we recommend that any new, deep well construction on the Ponders site be accomplished as follows:

1) Placement of a 24-inch temporary casing to approximately 200 feet.

2) Set a 20-inch casing to this depth and install an aquifer seal in the annular space be-tween the two casings as the 24-inch casing is withdrawn.

3) Proceed with drilling using 16-inch casing down to 600 feet. This should identify the Aq-uifer C and E sequences, if present.

4) OPTIONAL: if desired, exploration drilling using 12-inch casing could proceed to a depth of 800 feet to determine if Aquifer G is present.

5) The well would be completed in the better of Aquifer E or Aquifer G (if drilled). A screen assembly will be installed, likely using a gravel-pack design. Screen development to re-move fine-grained materials from the borehole will then be accomplished.

6) Once screen development is complete, variable-rate and constant-rate well tests will be performed, water quality collected, and the well rated for final production.

Based on the Districts other wells, static water levels in Aquifer E, if present, are expected to be between 80 and 100 feet below ground. Our standard recommendation for drawdown levels during pumping is not to exceed 100 feet of total drawdown below the static level. Thus, the expected pump setting depth would be between 200 and 250 feet below ground. Two Aquifer E wells on this site might require additional drawdown to accommodate the interference ef-fects of both wells pumping concurrently. This could extend the pump setting depth to as low as 300 feet. The existing Ponders property is sufficient in size to accommodate one additional well within the set-back requirements imposed for a water well. It may be possible to place two wells on the property if a variance from the set-back requirements can be successfully obtained from the Departments of Ecology and Health for at least one of the wells (possibly both, depending on their placement on the property). If a deep well as described above is to be drilled on the site, then the planned placement of the deep aquifer seal will make the variance request stronger and more likely to be approved.


Expected Costs

Drilling of a deep production well at this site using the approach listed above is estimated to cost about $325,000 for a completed 16-inch well or about $400,000 if the 12-inch exploration drilling is added, and total about $425,000 if a production well is completed in Aquifer G. State and local taxes are not included. Water quality analyses are assumed to be handled by the Dis-trict. Hydrogeological services for the well drilling project will be approximately $55,000 for the 16-inch production well or $65,000 for the deeper exploration/production well.

A contingency category should also be considered to allow for temporary testing of Aquifer C if the zone is encountered. This process would include pausing the 16-inch drilling, setting a tem-porary screen, a short screen-development period, and then testing to identify aquifer and wa-ter quality parameters. The screen would then be removed and drilling can then resume. Tem-porary testing such as this is expected to require between $10,000 and $15,000, plus tax. About $5,000 to $6,000 would also be needed for hydrogeological services. A contingency cat-egory of $21,000 plus tax is recommended.

Additional Considerations

Addition of a successful deep well at the Ponders site may impact some of the other actives on the site. One or the other of the existing wells may need to be replaced based on their remain-ing lifespan. Identifying where these replacement wells would be placed is warranted prior to drilling the deep well.

Also, one or the other of the existing wells may need to be decommissioned (if replaced or space constraints force a relocation of one). Decommissioning one of these shallow wells is expected to cost about $20,000, plus tax. Extensive hydrogeological and engineering services are not anticipated to be needed (plan on less than $5,000).

The final consideration is that expected production from one or two new deep wells is consid-ered unlikely to fully replace the existing wells. Therefore, some amount of water production and attendant water rights may still need to be made up elsewhere. This will be dealt with in more detail in Technical Memorandums 2 and 3.

Summary

Drilling a deep well on the Ponders wellfield site is feasible and appropriate to identify a source aquifer that will not require treatment for PCE. A single well is not likely to fully replace the pro-duction levels of the existing wells. A second new, deep well on the site will increase the total withdrawal but the combined total may not fully replace the existing production level. Treat-ment for inorganic secondary water quality constituents from iron, manganese, or hydrogen sulfide also may be needed. Water rights processing is not expected for any new on-site wells, but any remainder of the allocated totals that are not produced at the Ponders location may re-quire water rights processing if the District wishes to move them elsewhere.

The statements, conclusions, and recommendations provided in this report are to be ex-

clusively used within the context of this document. They are based upon generally ac-

cepted environmental and hydrogeologic practices and are the result of analysis by Rob-

inson Noble, Inc. staff. This report, and any attachments to it, is for the exclusive use of

Lakewood Water District and Kennedy/Jenks Consultants. Unless specifically stated in

the document, no warranty, expressed or implied, is made.


WELL L-1, L-2, L-3WELL L-1, L-2, L-3WELL L-1, L-2, L-3


WELL S-1WELL S-1WELL S-1

WELL E-3WELL E-3WELL E-3

WELL D-3WELL D-3WELL D-3


WELL Q-1, Q-2, Q-3WELL Q-1, Q-2, Q-3WELL Q-1, Q-2, Q-3

WELL K-1,K-2WELL K-1,K-2WELL K-1,K-2


WELL F-2WELL F-2WELL F-2




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Well Located in Aquifer G

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Technical Memorandum 2 Lakewood Water District

Ponders Wellfield Alternatives Analysis Date: May 28, 2015 To: Michael Norton, P.E. Kennedy/Jenks Consultants cc: Milt Larson, P.E. Kennedy/Jenks Consultants From: Burt G. Clothier, LHG

Construction of New Deep Source Wells As a follow-on to our Technical Memorandum 1, Robinson Noble was tasked with describing op-tions and potential costs for the development of new source wells that would be used to replace the production quantity at the Ponders wellfield. Given the size of the Ponders Wellfield’s water right allocation of 2,800 gallons per minute (gpm), more than one well, and possibly more than one site, will be needed to fully use the allocation.

We met with the District and the consultant team to discuss possible well locations that should be considered. Six possible sites were identified: The District-owned Scotts Well G-1/G-2 Wellfield and Well R-1 property and non-District properties at a vacant lot at 120th Street SW and 47th Ave SW, Tyee Elementary School, Woodbrook Middle School, and Springbrook Park (Figure 1). We ranked the sites and the first three were selected for additional consideration based on site size (including set-back requirements), infrastructure needs, water rights considerations, expected aquifer condi-tions (including both water quantity and quality) and the ease of site access.

The general hydrogeologic conditions and water quality considerations for each of these sites be-low was similar to those expected at the Ponders location. See Technical Memorandum 1 (TM 1) for a discussion of these conditions.

Well R-1/112th Street About a mile north of the Ponders wells is Well R-1 (Figure 2). The well is completed in Aquifer E between depths of 494 and 551 feet and has a production rate of 1,500 gpm. A little over a half mile northwest of Well R-1 are Wells K-1 and K-2, also completed in Aquifer E at depths between 504 and 571, and 497 and 572 feet respectively. Well K-1 produces 1,000 gpm and K-2 1,200 gpm. Well F-2 is located about ¾-mile northeast of Well R-1 and is completed in Aquifer E between 480 and 535 feet and produces 1,000 gpm. All of these wells exhibit good water quality and do not require treatment.

The 112th Street property is sufficiently large to accept up to two additional wells if spaced relatively close together. It’s probably not practical to complete more than two wells in Aquifer E at this site, so the third well would target Aquifer A. Based on the drilling log for Well R-1 Aquifer C is either very limited or not present. Aquifer A appears present but was not tested or otherwise quantified

2105 South C Street 17625 130th Avenue NE, Suite 102 Tacoma, Washington 98402 www.robinson-noble.com Woodinville, Washington 98072 P: 253.475.7711 | F: 253.472.5846 P: 425.488.0599 | F: 425.488.2330

during drilling, so only one well is being recommended in Aquifer A at this time. Maximum produc-tion is assumed to be 1,000 gpm from this shallow Aquifer A system. Much like at the Ponders site, a second Aquifer E well is not expected to exceed 1,000 gpm. Water quality in both aquifers is an-ticipated to be good and treatment will likely be unnecessary.

Even if the combination of a shallow well and a deep well proves successful, it is not expected that the full 2,800 gpm from the Ponders water right could be produced at the 112th Street site.

120th Street property A currently vacant property along 120th Street SW and 47th Avenue SW (Figure 3) has been identi-fied as a possible well site if the District chooses to acquire it from the current owner. This site is sufficiently large to support up to two wells. Based on its location in proximity to the McChord por-tion of JBLM there is the potential that shallow aquifer drilling could encounter contamination. While unconfirmed, it may be prudent from a planning perspective to assume the shallow Aquifer A should be skipped in favor of deeper systems. Drilling on this site is therefore assumed to target Aquifers C or E. Aquifer E is preferred since, based on the Districts experience at the F, K and R well sites, that system is likely more productive than would be expected for Aquifer C. That said, if initial drilling determines a significant production capability in Aquifer C, then new wells could be completed at this shallower depth or production wells finished in both Aquifers C and E could be established. (In this less likely event, it might be possible to develop three wells on the site)

For this effort, we assume only two wells with Aquifer E as the target production zone. This would result in a scenario very similar to that proposed for deep drilling at the Ponders site. For planning purposes, we assume water quality treatment will be needed to address iron, manganese and/or hydrogen sulfide. Unless conditions allow for three wells to be drilled on this property, the site it is unlikely to produce the full Ponders water right allocation.

Scotts G Wellfield The Well G-1 and G-2 wellfield produces from Aquifer A (Figure 4). Based on property size, near-by infrastructure and expected hydrogeologic conditions, this site is considered favorable for de-velopment of one or more deep wells, possibly even an additional shallow well. However, this site is currently under-producing its allocated water rights and it was identified as one of the potential locations for future deep wells to use the Abitibi water rights to provide water to the District’s wholesale clients. So, installation of new deep wells to make use of the Ponders water rights allo-cation might then pose a potential conflict with use of the site for future wholesale production un-der Abitibi.

With the new additional property acquired by the District to the south of the wells, there is sufficient space available to consider several new wells on this expanded site. It may be possible to add a third Aquifer A production well if the distances between wells will allow for conjunctive use without imposing significant interference drawdown between the wells. However, as noted, the site has available water rights, so we presume that any new Aquifer A well will operate under these existing rights. Therefore, the proposed well site at the south end of the property is reserved for that future well.

Likewise, use of the site for production under the Abitibi water rights is a consideration. While the site is probably capable of sustaining two deep Aquifer E wells, we assume that at least one of these wells would be reserved for future use under the wholesale water rights. This leaves the other well as a possible production site for the Ponders water right. For planning purposes, we assume production of about 1,000 gpm from this new Aquifer E well.


As an additional alternative, a separate well targeting Aquifer C could be installed. If such a well were successful, then this new well could operate under the Ponders water right. We estimate that an Aquifer C well might make about 500 gpm at this site. Based on inorganic water quality results for several wells to the east owned by Parkland Light and Water and the City of Tacoma, water quality in Aquifer C is variable. For planning purposes, treatment to address high iron, manganese and/or hydrogen sulfide should be assumed. Water levels in this system should be about 50 feet below ground and the screened zone around 300 feet or so leaving up to about 250 feet of availa-ble drawdown.

With only one well in Aquifer E and another in Aquifer C, the total production using the Ponders water rights will be up to 1,500 gpm. If a second, successful deep well can also be assigned to produce under the Ponders water rights (instead of exercising the Abitibi rights), then it may be possible to replace the full Ponders allocation at this location.

Expected Costs Well drilling costs will vary according to the target aquifer depth. A shallow well to complete and test a well in Aquifer A is anticipated to costs about $140,000. This assumes a drilling depth of about 200 feet using cable-tool methods and a 24-inch casing. Hydrogeological services will add approximately $35,000.

A well completed in Aquifer C will require about $205,000, assuming a drilling depth of about 350 feet and a final casing size of 16 inches. Hydrogeological services will add approximately $45,000.

Costs for an Aquifer E well will be the same as discussed in TM 1 at $325,000 for 16-inch drilling to 600 feet plus tax and about $55,000 for hydrogeological services.

The well drilling and completion costs do not include tax.

Additional Considerations Any of the three suggested locations will require a water rights change in order to move the point of withdrawal of the Ponders allocation to the selected site. It appears probable that more than one site will be needed to develop sufficient production to fully use the Ponders water rights. Therefore, we recommend that any proposed water rights change process include all of the potential well lo-cations as additional points of withdrawal (POW) under a single application process rather than as separate applications for each site. This should save time and effort on the processing, even if one or more of the future POW sites has not been finalized at the time of the water rights change re-quest.

Several of the alternate well locations might require a request for variance from the 100-foot sani-tary control radius requirements. So long as the well location is within about 75 feet of the nearest property line, we believe we can make a successful case for granting of a variance based on the geologic site conditions and proposed deep surface seal (as discussed in TM 1).

Summary Drilling at one or more of the locations discussed above, along with a change of the Ponders water rights, should allow the District to make full use of those water rights. Currently, we assume a combination of sites will be needed but that the final selection of those sites will need to incorpo-rate considerations other than hydrogeology and well technology. These considerations would in-clude: competing long-term plans to develop other water rights, Abitibi in particular; implementa-tion; and financial. From a hydrogeological perspective, each of the sites is viable for new well


construction (within the limits discussed above), so we expect that those other considerations may dominate the selection process.

The statements, conclusions, and recommendations provided in this report are to be exclu-sively used within the context of this document. They are based upon generally accepted en-vironmental and hydrogeologic practices and are the result of analysis by Robinson Noble, Inc. staff. This report, and any attachments to it, is for the exclusive use of Lakewood Water District and Kennedy/Jenks Consultants. Unless specifically stated in the document, no war-ranty, expressed or implied, is made.



WELL L-1, L-2, L-3WELL L-1, L-2, L-3WELL L-1, L-2, L-3






WELL Q-1, Q-2, Q-3WELL Q-1, Q-2, Q-3WELL Q-1, Q-2, Q-3

WELL K-1, K-2WELL K-1, K-2WELL K-1, K-2


WELL F-2WELL F-2WELL F-2




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LWD Boundary

Tyee ParkTyee ParkElementary SchoolElementary School

Tyee ParkElementary School


WoodbrookWoodbrookMiddle SchoolMiddle SchoolWoodbrookMiddle School



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PROPOSEDPROPOSEDWELL R-3WELL R-3

PROPOSEDWELL R-3

PROPOSEDPROPOSEDWELL R-2WELL R-2PROPOSEDWELL R-2

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Alternative Sites


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Appendix B

Capital Cost Tables

Documents

Table of Contents - Lakewood · Figure 6-5: Scotts Wellfield – Proposed Facilities . Figure 7-1: Hybrid Alternative – Well Location Map . Figure 7-2: Ponders Wellfield – Proposed