Water Treatment Plant Facility Planjwcwater.org/wp-content/uploads/2015/02/Agenda-Item-6A-JWC-WTP-Facility-Plan-Report_4...This Water Treatment Plant Facility Plan (Facility Plan)

F A C I L I T Y P L A N R E P O R T

Water Treatment Plant Facility Plan

Prepared for

Joint Water Commission

January 2017 Updated April 2018

CH2M HILL Engineers, Inc. 2020 SW Fourth Avenue Suite 300 Portland, OR 97201-4973

WT1010161153PDX III

Contents Section Page

Acronyms and Abbreviations ............................................................................................................ vii

Executive Summary ....................................................................................................................... ES-1 Background and Purpose ............................................................................................................ ES-1 Expansion to 85 MGD ................................................................................................................. ES-2 Seismic Resiliency Upgrades ....................................................................................................... ES-7 Interim Expansion Project ........................................................................................................... ES-9 Future Expansion Project .......................................................................................................... ES-10

1 Introduction ................................................................................................................................ 1-1 1.1 Purpose ............................................................................................................................ 1-1 1.2 Background ...................................................................................................................... 1-2 1.3 Facility Planning Process .................................................................................................. 1-4 1.4 Acknowledgements ......................................................................................................... 1-5

2 Planning Criteria .......................................................................................................................... 2-1 2.1 Water Source and Available Supply ................................................................................. 2-1

2.1.1 Current Water Rights .......................................................................................... 2-1 2.1.2 Future Sources of Supply .................................................................................... 2-4

2.2 Water Quality Goals ......................................................................................................... 2-4 2.3 Partner Demand Projections ........................................................................................... 2-5 2.4 Joint Water Commission Water Treatment Plant Capacity Goal Definitions .................. 2-6 2.5 Seismic Level of Service Goals ......................................................................................... 2-6 2.6 Joint Water Commission Planning Schedule and Milestones .......................................... 2-7

2.6.1 Expansion to 85 Million Gallons per Day ............................................................ 2-7 2.6.2 Seismic Resiliency Project ................................................................................... 2-7 2.6.3 Interim Expansion Project ................................................................................... 2-7 2.6.4 Future Expansion Project .................................................................................... 2-8

3 Seismic Improvements Plan ......................................................................................................... 3-1 3.1 Previous Seismic Analysis Work ....................................................................................... 3-1 3.2 Life Safety Mitigation Approach ...................................................................................... 3-1 3.3 Water Treatment Plant Seismic Resiliency Approach ..................................................... 3-2

4 Plant Capacity Summary .............................................................................................................. 4-1 4.1 Hydraulic Analysis ............................................................................................................ 4-1 4.2 Unit Process Capacity Summary ...................................................................................... 4-1 4.3 Winter Sustained Capacity ............................................................................................... 4-1

5 Facility Evaluation and Alternative Selection ................................................................................ 5-1 5.1 Supply and Treatment Processes ..................................................................................... 5-1

5.1.1 Required Treatment Capacity and Water Loss ................................................... 5-1 5.1.2 Raw Water Intake and Pumping ......................................................................... 5-2 5.1.3 Raw Water Pipeline ............................................................................................ 5-4 5.1.4 Rapid Mix Facility ................................................................................................ 5-5 5.1.5 Flocculation and Sedimentation ......................................................................... 5-5 5.1.6 Settled Water Conveyance ................................................................................. 5-7 5.1.7 Filtration .............................................................................................................. 5-9

CONTENTS

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IV WT1010161153PDX

5.1.8 Clearwell and Disinfection Contact Time .......................................................... 5-11 5.1.9 Finished Water Pumping................................................................................... 5-12 5.1.10 Chemical Systems ............................................................................................. 5-12

5.2 Solids Handling Process ................................................................................................. 5-12 5.2.1 Waste Washwater Surge, Recycle, and Clarification ........................................ 5-13 5.2.2 Sedimentation Basin Solids Conveyance .......................................................... 5-15 5.2.3 Solids Dewatering ............................................................................................. 5-16 5.2.4 Solids Disposal .................................................................................................. 5-18

5.3 Non-process Facilities .................................................................................................... 5-18 5.3.1 Operations, Maintenance, and Chemical Buildings .......................................... 5-18 5.3.2 Electrical Systems ............................................................................................. 5-19 5.3.3 Sustainability ..................................................................................................... 5-20

5.4 Future Treatment Processes .......................................................................................... 5-21

6 Expansion to 85 MGD and Related Improvements ........................................................................ 6-1 6.1 Project Definition ............................................................................................................. 6-1

6.1.1 Project Components ........................................................................................... 6-1 6.1.2 Hydraulics ........................................................................................................... 6-4 6.1.3 Capacity............................................................................................................... 6-4 6.1.4 Winter Sustained Capacity .................................................................................. 6-5

6.2 Project Schedule .............................................................................................................. 6-6 6.3 Project Budget ................................................................................................................. 6-6

6.3.1 Project Budget by Project Component ............................................................... 6-6 6.3.2 Joint Water Commission Partner Cost Allocation ............................................. 6-12

7 Seismic Resiliency Upgrades ........................................................................................................ 7-1 7.1 Project Definition ............................................................................................................. 7-1

7.1.1 Project Components ........................................................................................... 7-1 7.1.2 Capacity............................................................................................................... 7-2

7.2 Project Schedule and Phasing .......................................................................................... 7-4 7.3 Project Budget ................................................................................................................. 7-4 7.4 Project Planning Recommendations ................................................................................ 7-6

8 Interim Expansion Plan ................................................................................................................ 8-1 8.1 Project Definition ............................................................................................................. 8-1 8.2 Project Components ........................................................................................................ 8-1

9 Future Expansion Plan ................................................................................................................. 9-1 9.1 Project Definition ............................................................................................................. 9-1 9.2 Project Components ........................................................................................................ 9-1

10 References .............................................................................................................................. 10-1

Appendices

A TM 2-9: JWC WTP Facility Plan Alternatives Analysis B TM 2-10: JWC WTP Hydraulic Analysis C TM 2-11: JWC WTP Facility Plan Cost Estimating Criteria D TM 2-12: JWC WTP Review of Seismic Assessment and Approach

CONTENTS

Section Page

WT1010161153PDX V

Tables

Table ES-1. Components for 2019 Expansion to 85 Million Gallons per Day Project and Related Improvements ............................................................................................................................. ES-3

Table ES-2. Estimated 2019 Expansion to 85 Million Gallons per Day Project Budget ............................ ES-5 Table ES-3. Project Allocations by Partner ............................................................................................... ES-6 Table ES-4. Project Budget by Partner ..................................................................................................... ES-7 Table ES-5. Project Components for Seismic Resiliency Upgrades .......................................................... ES-8 Table ES-6. Project Components Included in the Interim Expansion Plan ............................................... ES-9 Table ES-7. Project Components Included in Future Expansion Plan .................................................... ES-11 Table 2-1. Joint Water Commission Water Rights Summary ..................................................................... 2-2 Table 2-2. Nonpeak Season Municipal Water Rights Available at Joint Water Commission Water

Treatment Plant ............................................................................................................................ 2-3 Table 2-3. Peak Season Municipal Water Rights Available at Joint Water Commission Water Treatment

Plant .............................................................................................................................................. 2-3 Table 2-4. Joint Water Commission Partner Demand Projections ............................................................ 2-5 Table 2-5. Level of Service Goals Following Seismic Event ........................................................................ 2-6 Table 3-1. Comparison of Life Safety Improvements Included in 2015 Capital Improvement Program

Update and 2016 Facility Plan ...................................................................................................... 3-1 Table 3-2. Proposed Seismic Resiliency Approach for 85 Million Gallons per Day Post-Seismic Capacity 3-2 Table 4-1. Existing Unit Process Capacity .................................................................................................. 4-2 Table 5-1. Backwash Surge, Recycle, and Clarification Design Criteria ................................................... 5-14 Table 5-2. Solids Dewatering Design Criteria ........................................................................................... 5-18 Table 5-3. Provisional Health-Based Water Guideline Values for Four Cyanotoxins (ppb or µg/L), Oregon

Health Authority, June 17, 2015 ................................................................................................. 5-21 Table 5-4. Performance of Advanced Treatment Processes Against Common Contaminants ............... 5-22 Table 6-1. Components for 2019 Expansion to 85 Million Gallons per Day Project and Related

Improvements ............................................................................................................................... 6-1 Table 6-2. 2019 Expansion to 85 Million Gallons per Day Project Unit Process Capacity ....................... 6-11 Table 6-3. Estimated 2019 Expansion to 85 Million Gallons per Day Project Budget by Component..... 6-12 Table 6-4. Project Allocations by Partner ................................................................................................ 6-13 Table 6-5. Project Budget by Partner ....................................................................................................... 6-13 Table 7-1. Project Components for Seismic Resiliency Upgrades.............................................................. 7-2 Table 7-2. Project Budget by Process Component..................................................................................... 7-6 Table 8-1. Project Components Included in Water Treatment Plant Interim Expansion Facility Plan ...... 8-1 Table 9-1. Project Components Included in Future Expansion Facility Plan .............................................. 9-1

Figures

Figure ES-1. Joint Water Commission Water Treatment Plant Expansion History .................................. ES-2 Figure ES-2. Water Treatment Plant Layout After 2019 Expansion to 85 Million Gallons per Day

and Related Improvements ........................................................................................................ ES-6 Figure ES-3. Layout of Joint Water Commission After the Seismic Resiliency Upgrades to 85 Million

Gallons per Day ........................................................................................................................... ES-8 Figure ES-4. Layout of Joint Water Commission Water Treatment Plant After Interim Expansion ...... ES-10 Figure 1-1. Process Flow for Existing Treatment Process .......................................................................... 1-3 Figure 1-2. Process Flow Diagram for Existing Solids Process ................................................................... 1-3 Figure 1-3. Joint Water Commission Water Treatment Plant Expansion History ...................................... 1-4 Figure 2-1. Joint Water Commission Water Sources ................................................................................. 2-1

https://delivery.ch2m.com/projects/672638/02_FacilityPlan/06_Report/Update%20Jan%202018/JWC%20WTP%20Facility%20Plan%20Report_UPDATE.docx#_Toc505074183

CONTENTS

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VI WT1010161153PDX

Figure 2-2. Joint Water Commission Water Treatment Plant Maximum Day Demand by Partner ........... 2-5 Figure 5-1. Water Loss and Recycling Schematic ....................................................................................... 5-2 Figure 5-2. Spring Hill Pumping Plant Profile ............................................................................................. 5-3 Figure 5-3. Approximate location of the Raw Water Pipelines in relation to the Spring Hill Pumping Plant

and Rapid Mix Facilities................................................................................................................ 5-4 Figure 5-4. Selected Rapid Mix Alternative ................................................................................................ 5-5 Figure 5-5. Existing Flocculation/Sedimentation Basins with Capacities in Million Gallons per Day ........ 5-6 Figure 5-6. Selected Flocculation/Sedimentation Alternative ................................................................... 5-7 Figure 5-7. Existing Settled Water Flume ................................................................................................... 5-8 Figure 5-8. Selected Settled Water Conveyance Alternative ..................................................................... 5-8 Figure 5-9. Isometric of Existing Filter Structure ....................................................................................... 5-9 Figure 5-10. Filtration System Process Flow ............................................................................................ 5-10 Figure 5-11. Isometric of New Filter Design (Lower Level) ...................................................................... 5-10 Figure 5-12. Isometric of Existing Clearwell ............................................................................................. 5-11 Figure 5-13. Existing Solids Handling Process Flow ................................................................................. 5-13 Figure 5-14. Existing Solids Handling System Layout ............................................................................... 5-13 Figure 5-15. Expansion to 85 Million Gallons per Day Backwash Recycle Layout ................................... 5-15 Figure 5-16. Existing Sedimentation Basin Solids Conveyance System ................................................... 5-16 Figure 5-17. Existing Solids Dewatering System ...................................................................................... 5-17 Figure 5-18. Existing Water Treatment Plant Electrical System .............................................................. 5-19 Figure 6-1. Water Treatment Plant Layout after 2019 Expansion to 85 Million Gallons per Day Project

and Related Improvements .......................................................................................................... 6-5 Figure 6-2. Process Flow Diagram showing the Water Treatment Plant after the 2019 Expansion to 85

Million Gallons per Day Project .................................................................................................... 6-7 Figure 6-3. 2019 Expansion to 85 Million Gallons per Day Project Hydraulic Profile ................................ 6-9 Figure 7-1. Layout of Joint Water Commission Water Treatment Plant after the Seismic Resiliency

Upgrades to 85 Million Gallons per Day ....................................................................................... 7-3 Figure 7-2. Seismic Resiliency Upgrades to 85 Million Gallons per Day—Process Flow Diagram ............. 7-3 Figure 7-3. Phase 1 of the Seismic Resiliency Project ................................................................................ 7-5 Figure 7-4. Phase 2 of the Seismic Resiliency Project ................................................................................ 7-5 Figure 7-5. Phase 3 of the Seismic Resiliency Project ................................................................................ 7-5 Figure 8-1. Layout of Joint Water Commission Water Treatment Plant after Interim Expansion ............. 8-4 Figure 8-2. Water Treatment Plant Interim Expansion Process Flow Diagram ......................................... 8-5 Figure 9-1. Future Expansion Process Flow Diagram ................................................................................. 9-2

Facility Plan Updates:

The January 2018 Facility Plan Update modified the assumptions regarding the “Interim” and “Future” expansion projects. This update did not included changes to the Expansion to 85 MGD project section to align the Facility Plan with the final Expansion to 85 MGD project scope of work. As such, the scope of work for the Expansion to 85 MGD project described in the Facility plan does not completely match the actual scope of work for the project.




WT1010161153PDX VII

Acronyms and Abbreviations BAC biological-activated carbon BWPS backwash pump station

°C degrees Celsius CFD computational fluid dynamic cfs cubic feet per second CH2M CH2M HILL Engineers, Inc. CIMP capital improvement maintenance projects CIP capital improvement program Cl2 chlorine CT chlorine concentration x contact time CWS Clean Water Services

DBP disinfection byproduct

Facility Plan Water Treatment Plant Facility Plan FW finished water FWPS finished water pump station

GAC granular-activated carbon gpm gallons per minute gpm/sf gallons per minute per square foot

hp horsepower HVAC heating, ventilation, and air conditioning

JWC Joint Water Commission

kcmil thousand circular mil kV kilovolt kVA kilovolt-ampere

lbs/cf pounds per cubic foot lbs/day pounds per day lbs/sf pounds per square foot lbs/sf-day pounds per square foot per day lbs/year pounds per year LOS level of service

µg/L micrograms per liter MCC motor control center MG million gallons mg/L milligrams per liter MGD million gallons per day MV medium voltage

N/A not applicable NMMVS New Main MV Switchgear NTU nephelometric turbidity unit

OMMVS Old Main MV Switchgear

PAC powder-activated carbon PGE Portland General Electric

ACRONYMS AND ABBREVIATIONS

VIII WT1010161153PDX

ppb parts per billion Project 2019 Expansion to 85 MGD Project

Reclamation U.S. Department of the Interior Bureau of Reclamation

sf square feet or foot SHPP Spring Hill Pumping Plant

TAC Technical Advisory Committee TBD to be determined TVWD Tualatin Valley Water District

UV ultraviolet

WMCP Water Management and Conservation Plan WTP water treatment plant

WT1010161153PDX ES-1

Executive Summary This Water Treatment Plant Facility Plan (Facility Plan) is part of the expansion of the Joint Water Commission (JWC) Water Treatment Plant (WTP) project. This project is referred to as the Expansion to 85 Million Gallons Per Day (MGD), Facility Plan, and Other Related Improvements (Expansion to 85 MGD Project). As part of this process, related future projects, including seismic resiliency upgrades, additional expansion, and potential future treatment processes, were considered to align the current improvements with these future upcoming plans. The Facility Plan describes the planning process, design criteria, and planned improvements.

Background and Purpose The JWC comprises four partner agencies: City of Hillsboro, City of Forest Grove, City of Beaverton, and the Tualatin Valley Water District. Each partner has a partial ownership in the JWC WTP. The JWC WTP takes water from the Tualatin River via an intake and pump station shared with the Tualatin Valley Irrigation District and owned by the U.S. Department of the Interior Bureau of Reclamation. Water is pumped from this intake to the WTP approximately 0.5 mile away. The water is treated in the conventional WTP consisting of chemical injection and rapid mixing, flocculation, sedimentation, filtration, and final chlorine disinfection before being distributed to the partner agencies. The current WTP has a rated capacity of 75 MGD, but has only produced up to 68 MGD due to capacity limitations within the WTP and customer demands.

Water demands of the partner agencies are continuing to increase both due to growth in their service areas and development of new sources. As a result, additional water supply is projected to be needed in the immediate and long-term future. Although the primary focus of the capacity discussion is to meet the peak summer demands, baseline winter demands will also increase at a faster rate due to construction of Aquifer Storage and Recovery (ASR) wells by several of the partner agencies.

The JWC WTP was originally constructed in 1976. The plant underwent major expansions in approximately 1986, 1992, and 2000. The most recent treatment plant expansion was the Near-Term Improvements project completed in 2007, which expanded capacity, added the Fern Hill Reservoir No. 2, and established the engineered solids drying beds. The backup power facility was not a capacity improvement project but was recently completed in 2016. Figure ES-1 (next page) shows when each major component of the JWC WTP was completed.

In 2015, JWC completed a capital improvement program (CIP) update (Carollo Engineers, 2015), which presented a unified plan based on multiple previous studies and reports. The overarching concept for the CIP included plans for expanding the JWC WTP to 85 MGD around 2020.

Among the previous studies considered was the Seismic Hazard Mitigation Study of the JWC WTP (Carollo Engineers, 2008). This study defined the risks associated with the liquefiable soils at the site and identified the older facilities that do not have the capacity to withstand liquefaction. As a result, the JWC plans to complete a major seismic resiliency upgrade project following the commissioning of the Willamette Water Supply Program, after 2026. This JWC seismic upgrade would assure a higher level of confidence that the WTP would be operational following a subduction zone earthquake event. This upgrade would involve replacing vulnerable plant infrastructure.

This Facility Plan builds on the 2015 CIP update by further defining the future water treatment system and process improvements and solids handling at the JWC WTP while developing an approach to implement future improvements. This approach includes detailed plans for the current 2019 Expansion to 85 MGD Project and conceptual plans for both the Seismic Resiliency Upgrades, and Ultimate WTP Buildoutinterim expansion, and future expansion projects.

EXECUTIVE SUMMARY

ES-2 WT1010161153PDX

This Facility Plan provides guidance and documents the evaluations that were considered to align the current WTP improvements with currently understood long term goals and plans for the WTP. This plan will be refined and implemented based on future master plans and CIP updates as determined by the Joint Water Commission (Commission).

Figure ES-1. Joint Water Commission Water Treatment Plant Expansion History

Expansion to 85 MGD The 2019 Expansion to 85 MGD Project includes four major objectives:

• Remove hydraulic bottlenecks in the existing WTP to provide 75-MGD peak capacity for all JWC partners. (Capacity is further defined in Section 2.4.)

• Expand the WTP capacity to provide 85-MGD peak capacity.

• Implement previously identified seismic life-safety projects for the safety of plant staff and visitors.

• Complete previously identified capital improvement maintenance projects (CIMP).

Improvements to reach 75 MGD, seismic upgrades, and CIMP are necessary for all partners and will be funded based on the current prorated ownership of the WTP. However, the 10-MGD expansion from 75 to 85 MGD is being undertaken and funded by the City of Hillsboro and Tualatin Valley Water District and will increase their respective WTP ownership shares. This project is scheduled to be completed by June 30, 2019, to meet the water demands projected by these two partners.

Table ES-1 summarizes the improvements expected as part of the 2019 Expansion to 85 MGD Project. A comparison to the 2015 CIP is also provided. The most significant changes from the 2015 CIP include:

• Reconfiguration of the solids handling system to minimize stranded assets

• Installation of larger filters in response to the capacity limitations revealed during July 2015 peak demands

• Reduction in the scope of seismic improvements

LEGEND

1976 1986 1992

2000 2007 2016

Solids drying beds

Flocculation/ sedimentation

Backup generator

Filters

Finished water pump station 2


Operations building

Gravity thickeners

Surge basins

Clearwell

Caustic building

Basin G plate settlers

Sludge ponds

EXECUTIVE SUMMARY

WT1010161153PDX ES-3

The changes are described in more detail in this Facility Plan.

Table ES-1. Components for 2019 Expansion to 85 Million Gallons per Day Project and Related Improvements

Facility Proposed Improvements 75

MGD 85

MGD CIMP Seismic

Life Safety 2015 CIP Update

SHPP, raw water pump station

Increase capacity of pumps to 400 horsepower each

✓

✓

Add vortex suppression systems ✓

Make seismic improvements: nonstructural—restrain cabinets

✓ ✓

Make seismic improvements: structural ✓

Install rotating raw water trash screens ✓

Rapid mix facility

Remove fiberglass baffle wall ✓ ✓

Relocate jet injectors ✓

Remove weir to basins D through G ✓

Add flow meters and flow control valves for basins D through G and replace basins A/B flow meter

✓

✓

Upgrade flash mix pumps ✓

✓

Make seismic improvements: nonstructural—restrain grating

✓ ✓

Flocculation/ sedimentation basin

Install plate settlers in basins D through F ✓

✓

Improve sedimentation basin drains ✓

✓

Rehabilitate chain and flights in basins D through G

✓ ✓

Make seismic improvements: nonstructural—restrain basin G plate settlers

✓ ✓

Make seismic upgrades: structural ✓

Repair floor cracks in basins A through C ✓

Add hatches to basins A through C ✓

Settled water conveyance

Settled water pipeline connected from Basin D to existing and new filters (Included in filter yard piping cost)

✓ ✓

Add polymer mixing in new settled water pipe (Included in filter costs)

✓

Filters

Install two new filters (924 sf each) ✓ ✓

Install two new filters (426 sf each) ✓

Install new filter yard piping ✓ ✓

Paint filter 1 through 8 gallery piping and extend clearwell vents to atmosphere

✓ ✓

Replace media in filters 1 through 13 ✓

✓

Evaluate and repair settling in filter 13 ✓

Make seismic improvements: nonstructural—restrain HVAC equipment

✓ ✓

EXECUTIVE SUMMARY

ES-4 WT1010161153PDX



MGD 85

MGD CIMP Seismic


FWPS

Replace FW Pump 2 and 6

(replace FW Pump 1 as budget allows) ✓ ✓

Replace BW Pump 1 and 2 ✓ ✓

Make FWPS 1 seismic improvements: nonstructural—restrain HVAC and electrical equipment

✓ ✓

Make FWPS 2 seismic improvements: nonstructural—restrain cabinets

✓ ✓

Backwash surge and recycling

Construct new surge basin ✓

✓

Make new to old surge basin connection ✓

Upgrade existing recycle pump station ✓

Construct new recycle pump station ✓

Install a new gravity thickener ✓

Replace existing thickener mechanisms ✓

Solids dewatering

Construct new solids drying bed (bed 4) ✓ ✓

Construct second new solids drying beds (bed 5)

✓

Modify solids drying bed flow ✓

Decant pump station capacity increase ✓

Decant pump station flow meters ✓

Abandon gravity thickeners in place ✓

Chemical facilities

Upgrade chemical feed pumps ✓

✓

Replace chlorine feed lines to FWPS 1, FWPS 2, and settled water flume

✓

✓

Install chlorine residual monitoring ✓

Increase chemical containment capacity ✓

Operations building

Add water manager’s office ✓

Make seismic improvements: nonstructural—restrain cabinets and tanks

✓ ✓

Make seismic improvements: structural—reinforce office window

✓ ✓

Make seismic improvements: structural—foundation improvements

✓

General, site, and yard piping

Replace and rehabilitate two air compressors and air lines

✓ ✓

Replace septic tank and leach field ✓ ✓

Redirect waste from analyzers at pump stations 1 and 2

✓ ✓

Make seismic improvements: nonstructural—restrain sodium hydroxide tanks

✓ ✓

Make seismic improvements: nonstructural – anchor and brace electrical cabinets, duct

✓ ✓

EXECUTIVE SUMMARY

WT1010161153PDX ES-5



MGD 85

MGD CIMP Seismic


muffler and battery charger at MCC/Generator Building

(Construct sidewalks at basins and more parking as budget allows)

✓ ✓

General electrical and controls

Upgrade WTP communications network ✓

Studies and CIP updates

Conduct electrical assessment ✓

✓

Notes:

BWPS backwash pump station CIMP Capital Improvement Maintenance Project CIP capital improvement program FW finished water FWPS finished water pump station

HVAC heating, ventilation, and air conditioning MCC motor control center MGD million gallons per day sf square feet SHPP Spring Hill Pumping Plant WTP water treatment plant

Figure ES-2 shows the planned layout for the JWC WTP following the completion of the 2019 Expansion to 85 MGD Project. This project includes adding new plates in basins D through F, two new filters, a new surge basin, and two new solids drying beds.

The cost of the project is broken out between the 75-MGD and 85-MGD capacity projects as shown in Table ES-2. The estimates provided are generally prepared as Class 4 estimates with an accuracy in the range of +50 percent to -30 percent of the cost shown. The cost of each facility component is provided in Section 6 and further detailed in Appendix B.

Table ES-2. Estimated 2019 Expansion to 85 Million Gallons per Day Project Budget

Facilities 75 MGD

Expansion

85 MGD Expansion

CIMP: 2016-2019

Phase I Seismic

2016-2019 Total

Totala $8,230,000 $17,740,000 $4,800,000 $430,000 $31,200,000

Total from 2015 CIP Updateb $3,000,000 $16,700,000 $6,300,000 $4,000,000 $30,050,000

Notes:

a The updated estimates provided are current as of June 2016 and generally prepared as Class 4 estimates with an accuracy in the range of +50 percent to -30 percent of the cost shown. The cost estimating approach is described further in Appendix B.

b The 2015 CIP Update is in 2014 dollars with an accuracy of +100 percent to -50 percent of the costs shown. If updated to the same cost basis as the current (2016) estimate, the total would be $31,800,000.

Notes:

CIMP Capital Improvement Maintenance Project CIP capital improvement program MGD million gallons per day

EXECUTIVE SUMMARY

ES-6 WT1010161153PDX

Figure ES-2. Water Treatment Plant Layout After 2019 Expansion to 85 Million Gallons per Day and Related Improvements

A summary of the partner allocations is shown in Table ES-3 and Table ES-4. Note that while the estimated cost for each facility upgrade has changed from the 2015 CIP Update (Carollo Engineers, 2015), each partner’s share in the project is within 3 percent of the original estimate.

Table ES-3. Project Allocations by Partner

Partner 75 MGD, Seismic Life-Safety,

and CIMP (percent) Expansion to 85 MGD (percent)

Tualatin Valley Water District 16.7 20.0

City of Hillsboro 45.0 80.0

City of Beaverton 25.0 N/A

City of Forest Grove 13.3 N/A

Notes:

CIMP Capital Improvement Maintenance Project MGD million gallons per day

EXECUTIVE SUMMARY

WT1010161153PDX ES-7

Table ES-4. Project Budget by Partner

Partner Total Projecta 75 MGD, Seismic,

and CIMPa Expansion to 85

MGDa 2015 CIP Update

Total Projectb

Tualatin Valley Water District $5,790,000 $2,240,000 $3,550,000 $5,570,000

City of Hillsboro $20,250,000 $6,060,000 $14,190,000 $19,380,000

City of Beaverton $3,370,000 $3,370,000 $0 $3,330,000

City of Forest Grove $1,790,000 $1,790,000 $0 $1,770,000

Total $31,200,000 $13,460,000 $17,740,000 $30,050,000

Notes:



CIMP Capital Improvement Maintenance Project MGD million gallons per day

Seismic Resiliency Upgrades The Seismic Resiliency Upgrades are planned to address significant seismic concerns related to the WTP meeting the post-seismic level of service goals described in Section 1. The original goal that factored into the selection and sizing of new facilities to be constructed was the goal to have a minimum of 42 MGD WTP capacity (average day demand) available immediately following or shortly after each of the seismic events. Rather than implementing a partial WTP replacement, JWC has elected to replace all vulnerable facilities in full. This will result in 85 MGD of seismically resilient capacity shortly after the design seismic events.

This project is expected to involve replacing most of the WTP facilities and buildings, with only a few newer (post-1998) facilities remaining, including the following:

• Flocculation/sedimentation basins D through G

• Finished water pump station (FWPS) 2

• New generator building (standby power)

• New filters and surge basin constructed for the expansion to 85 MGD

• Solids drying beds will remain in operation with no modifications

The new facilities will be built around the existing and operating WTP and require careful scheduling to maintain effective operations throughout the improvements, and include the following:

• New or upgraded raw water pump station

• Replace raw water transmission mains

• Replace rapid mix facility

• Replace flocculation/sedimentation basins A-C

• Replace filters 1 through 14

• Replace clearwell

• Replace FWPS 1

• Replace the operations and chemical building

• Upgrade disinfection from chlorine gas to onsite hypochlorite

EXECUTIVE SUMMARY

ES-8 WT1010161153PDX

The proposed plant layout is shown in Figure ES-3.

Figure ES-3. Layout of Joint Water Commission After the Seismic Resiliency Upgrades to 85 Million Gallons per Day

Table ES-5 summarizes the improvements expected as part of the Seismic Resiliency Upgrades. Refer to the 2008 Seismic Hazard Mitigation Study (Carollo Engineers, 2008) for details on seismic improvements to existing facilities.

Table ES-5. Project Components for Seismic Resiliency Upgrades

Facility Proposed Improvements for 85 MGD

SHPP, raw water pump station Upgrade or replace existing SHPP.

Raw water pipelines Replace two raw water pipelines

Rapid mix facility New rapid mix facility and yard piping

Flocculation/sedimentation basins Replace basins A through C with new basins H and I similar to basins D through G

Filters Replace existing filters 1 through 14 with new filters 17 through 22

Clearwell New 2.5-MG clearwell

FWPS Replace FWPS 1 with new FWPS 3 and construct foundation improvements for FWPS 2.

Backwash surge and recycling New washwater and solids facilities

EXECUTIVE SUMMARY

WT1010161153PDX ES-9

Table ES-5. Project Components for Seismic Resiliency Upgrades

Facility Proposed Improvements for 85 MGD

Chemical facilities New chemical facility (alum, polymer, powdered activated carbon)

New onsite sodium hypochlorite generation facility

Operations building New operations and maintenance building(s)

Notes:

FWPS finished water pump station MG million gallons MGD million gallons per day SHPP Spring Hill Pumping Plant

Facility improvement costs were estimated for the Seismic Resiliency Upgrades project based on the improvement summary discussed above. The estimated total cost in June 2016 dollars is $125,000,000. The costs are based on full replacement of seismically vulnerable facilities. These upgrades would result in a seismically resilient capacity of 85 MGD. Section 7 and Appendix B describe these further.

Ultimate Water Treatment Plant BuildoutInterim Expansion Project The timeline of the ultimate plant buildoutinterim expansion is currently undefined. Based on the partner demand projections included in Section 2, the ultimate plant buildoutinterim expansion likely will not occur until after 2040. During the facility planning process, the partners have elected to base Facility Plan ultimate buildoutInterim Expansion sizing around a working assumption of an ultimate peak summer plant capacity of 105 MGD, due to the available water rightsraw water supplies for the partners at the JWC WTP. The actual production capacity of the JWC WTP following future expansions after the current expansion to 85 MGD will be determined by the CommissionThe Commission will determine the timing and capacity of additional WTP expansions, with support from a future master plan update. Peak capacity is defined by the JWC as 3-days of sustained operation with all units, including pumps, in service. This will result in the rapid mix through flocculation/sedimentation basins being capable of producing 108 MGD of capacity to account for losses through the flocculation/sedimentation solids blowdown and filter backwash systems. The raw water pump station should will also be sized for 108 MGD, although the JWC recycles most water lost during the solids-handling process, and the likely typical raw water diversion will be less than 108 MGD but more than 105 MGD.

In addition to expanding the plant to reach its ultimatethe interim capacity, the ultimate plant buildout evaluation includes potential future treatment processes that may be required to account for changing source water quality or future regulations. Table ES-6 lists project components included in the ultimate WTP interim expansion facility plan to be added to the WTP following the completion of the 2026 Seismic Resiliency Project.

Table ES-6. Project Components Included in Ultimate Buildoutthe Interim Expansion Water Treatment Plant Facility Plan

Facility Description of Improvements

Raw water pump station New raw water pump station (location TBD) or new raw water pipeline from Hagg Lake

Land acquisition

Flocculation/sedimentation basins Construct additional plates in basins D through I

Increased flocculation capacity in basins D through I

Filters Two new filters (23 and 24)


EXECUTIVE SUMMARY

ES-10 WT1010161153PDX

Table ES-6. Project Components Included in Ultimate Buildoutthe Interim Expansion Water Treatment Plant Facility Plan


Solids dewatering New solids drying bed (bed 6)

New treatment facilities Potential ozone or UV treatment (TBD)

Notes:

MG million gallons TBD to be determined UV ultraviolet

Figure ES-4 shows the proposed site layout for the ultimate interim expansion of the JWC WTP. This represents the ultimate buildout of the WTPinterim expansion at 105 MGD with two potential future treatment systems which include the option to add ozone or UV treatment.

Figure ES-4. Layout of Joint Water Commission Water Treatment Plant After Ultimate BuildoutInterim Expansion

Future Expansion Project Similar to the interim expansion, the timeline of the future expansion is currently undefined. This expansion will take place sometime after the interim expansion. The primary goal of this expansion is

EXECUTIVE SUMMARY

WT1010161153PDX ES-11

assumed to be an increase in winter sustained capacity to expand aquifer storage recovery (ASR) capacity for the partners. Future expansion facility plan sizing is based on a future plant winter sustained capacity of 130 MGD as required to achieve expected long term water demands. This will require the treatment plant to achieve 130 MGD at least 80 percent of the time during winter conditions according to the winter sustained definition in Section 4. This will result in the rapid mix through flocculation/sedimentation basins being capable of producing 135 MGD of capacity to account for losses through the flocculation/sedimentation solids blowdown and filter backwash systems. The raw water pump station will also be sized for 135 MGD, although the JWC recycles most water lost during the solids-handling process, and the likely typical raw water diversion will be less than 135 MGD but more than 130 MGD. JWC will consider specific partner requirements for firm and winter sustained capacity before beginning this project to develop specific goals for peak, firm, and winter sustained capacity.

The Commission will determine the actual timing and capacity of the future WTP expansions, with support from a future master plan update. Table ES-7 lists project components included in the future expansion facility plan to be added to the WTP following the completion of the 2026 Seismic Resiliency Project.

Table ES-7. Project Components Included in Future Expansion Plan


Raw water pump station New raw water pumps

Flocculation/sedimentation basinsa

Construct two new basins J and K similar to basins D through I

Increase flocculation capacity in basins D through I

Filtersb Construct six new filters (25-30, 16 total)

Solids dewateringc Construct three new solids drying beds (beds 7, 8 and 9)

a Sizing criteria is based on 45 min flocculation time and 0.30 gpm/sf plate settler loading rate

b Sizing criteria is based on a winter filter loading rate of 7.2 gpm/sf and 8,500 gal/sf UFRV

c Sizing criteria is based on a winter loading rate of 480 lbs of solids per MG and an average winter flow of 120 MGD

Notes:

MG million gallons MGD million gallons per day TBD to be determined WTP water treatment plant

A full siting analysis of the future expansion was not performed as part of this facility plan. Note that the Seismic Resiliency Upgrades and interim expansion plan must allow space for additional flocculation/sedimentation basins and filters as part of this expansion.

SECTION 1

WT1010161153PDX 1-1

1Introduction

1.1 Purpose This Water Treatment Plant Facility Plan (Facility Plan) is part of the expansion of the Joint Water Commission (JWC) Water Treatment Plant (WTP) project. This project is referred to as the Expansion to 85 Million Gallons Per Day (MGD), Facility Plan, and Other Related Improvements (Expansion to 85 MGD Project).

In April 2015 the Commission adopted Resolution 124-J, a resolution approving the long term capital improvement plan (CIP), which:

• Identified multiple water treatment plant facilities that would fail during seismic events;

• Included plans for replacement of those facilities;

• Approved and provided justification for deferring construction of those replacement facilities to an undetermined time after 2026, when the Willamette Water Supply Program system would be available and the partners’ funding sources would be under less stress from other projects.

The Commission has approved design and construction of water treatment plant (WTP) upgrades and expansion that will increase WTP peak production capacity to 85 mgd to meet projected capacity needs of the partners for the near term (prior to the completion of the Willamette Water Supply project).

The current upgrade and expansion project will include construction of some new structures. The JWC partners recognized that these new structures should be designed and located with the future upcoming WTP structure and facility replacement project in mind, in order to avoid or minimize investing in new facilities that could then need to be replaced a second time to fit with the future upcoming WTP upgrade.

The Facility Plan has developed preliminary assumptions about build-out capacity, WTP processes, and WTP layout for an upcoming future WTP replacement program. The Facility Plan assumptions are guiding the design and location of the structures and facilities for the current upgrade and expansion project.

In the future, the Commission will continue to be responsible for making decisions on an updated Capital Improvements Plan (CIP) that identifies the water treatment plant facilities that should be built and when they should be built, including decisions on priorities and phasing. The current understanding is that the JWC member agencies will develop that updated CIP through the next master plan update. It is currently anticipated that the next master plan work will not begin earlier than FY 2020, after completion of the current WTP expansion project. However, the Commission will decide the timing of the master plan update project, which could begin at an earlier or later date.

The master plan update shouldIt is recommended that the master plan update involve a comprehensive analysis of all of the factors that need to be considered to develop a recommended long term JWC CIP and funding program for the replacement WTP facilities. The scope and goals of that master plan update will be determined by the Commission at the time the master plan is initiated, and supported by recommendations from the Managing Agency and the Operations Committee. Some items that are likely to be consideredrecommended for consideration for the scope of work include:

• Identifying goals for reliability, redundancy, and resiliency in the JWC water system.

• Incorporate updated near-term and long-term demand projections obtained from the JWC partners (identifying both total demand and demand on JWC system for each partner).

SECTION 1 – INTRODUCTION

1-2 WT1010161153PDX

• Addressing system risks, which include:

– Impacts of Scoggins Dam system improvements.

– Seismic risks to WTP and transmission facilities.

– Consideration of source water availability, including a range of risks due to climate change impacts.

– Potential need for new and/or updated water supply conveyance infrastructure such as a raw water pipeline from Scoggins Dam, a new or modified intake, and/or new intake screens.

• Evaluating approaches for coordinating improvements to and operations of the JWC system with those of other water supply systems.

• Evaluating costs of alternative approaches to and timelines for system improvements.

• Establishing priorities and timelines for replacement of WTP and transmission facilities.

• Coordinating with partners on probable funding sources and timing of funding availability.

In addition, the Commission could direct that the scope of the master plan update include evaluation of the relative priority to partners of improving transmission capacity resilience as compared to replacement of WTP facilities. JWC staff intends to explore grant funding opportunities for that part of the study.

Once completed and adopted by the Commission, the master plan CIP will guide timing and development of subsequent capital project budgets, but the Commission always retains the discretion to modify the CIP based on intervening events.

The Commission has not yet made any decisions about the timing for construction of the WTP replacement facilities since adopting Resolution 124-J approving deferral of construction until sometime after 2026. A variety of factors during the intervening period will inform the Commission’s decisions as to the schedule for construction of new improvements, including:

• Experience gained from the implementation and integration of the Willamette Water Supply System.

• Trends in demand growth.

• Potential changes to the UGB and service territories.

• Potential changes in costs and standards.

As part of the facility planning process described in this report, proposed future projects, including seismic resiliency upgrades, additional expansion, and potential future treatment processes, were considered to align the current improvements being conducted as a part of this project with these futureupcoming plans. The following sections describe the planning process, design criteria, and planned improvements.

1.2 Background The JWC comprises four partner agencies: City of Hillsboro, City of Forest Grove, City of Beaverton, and the Tualatin Valley Water District. Each partner has a partial ownership in the JWC WTP. The JWC WTP takes water from the Tualatin River via an intake and pump station shared with the Tualatin Valley Irrigation District and owned by the U.S. Department of the Interior Bureau of Reclamation (Reclamation). Water is pumped from this intake to the WTP approximately 0.5 mile away. The water is treated in the conventional WTP consisting of chemical injection and rapid mixing, flocculation, sedimentation, filtration, and final chlorine disinfection before being distributed to the partner agencies. The process flow diagram for the existing treatment system is shown in Figure 1-1 and the process flow diagram for the existing solids system is shown in Figure 1-2. The current WTP has a rated capacity of 75


WT1010161153PDX 1-3

MGD, but has only produced up to 68 MGD in July 2015. The peak capacity of the plant has not been documented; however, operations in 2015 indicated that the capacity is limited to less than 75 MGD and was operating near its maximum capacity during that event.

Figure 1-1. Process Flow for Existing Treatment Process

Figure 1-2. Process Flow Diagram for Existing Solids Process

Water demands of the partner agencies are continuing to increase both due to growth in their service areas and a reconfiguration of water sources. As a result, additional water supply is projected to be needed in the immediate and long-term future. Although the primary focus of the capacity discussion is to meet the peak summer demands, baseline winter demands will also increase at a faster rate due to construction of ASR wells by several of the partner agencies.

The JWC WTP was originally constructed in 1976. The plant underwent major expansions in approximately 1986, 1992, and 2000. The most recent treatment plant expansion was the Near-Term Improvements project completed in 2007, which expanded capacity, added the Fern Hill Reservoir No. 2, and established the engineered solids drying beds. The backup power facility was not a capacity

SPRING HILL

PUMP STATIONCLEARWELLRAPID MIX

BASIN

JET INJECTION

PUMPS

M

M

M

M

36" RW

42" RW

FILTERS

M

M

FLOCCULATION SEDIMENTATION

BASIN C

BASIN B

BASIN APD

SOLIDS

DIVERSION PS

SW

SW

BACKWASH WASTE

(TO SURGE BASIN)

FW

SW

SW

BWW

FINISHED WATER

(TO DISTR)

RIVER SOURCE

RECYCLED

WATER FROM

THICKENERS

REC

FINISHED WATER

(TO DISTR)

FINISHED WATER

PUMP STATION

BASIN D

BASIN E

BASIN F

BASIN G

CW

CW

CW

Spring Hill Pumping Plant

Rapid mix basin

Flocculation/sedimentation basins

Filters Clearwell Finished water pump station

SS

WW

RAPID MIX

WW

WW

REC

REC

REC

SS

BACKWASH

WASTE

SETTLED SOLIDS

SS

REC

SS

BWW

BWW

BWW

BWW

SLUDGE

DRYING BEDS

DECANT

PUMP STATION

REC

SOLIDS TO OFFSITEUD

SOL

SOLIDS DIVERSION

PUMP STATION

UNDERDRAIN

PUMP STATION

SOLIDS

LAGOONS

SS

FILTER BACKWASH

SURGE BASINS

RECYCLE PUMP

STATIONS

DECOMMISSIONED

GRAVITY THICKENERS

THICKENED SLUDGE

PUMP STATION

RAPID MIX

Surge basins

Recycle pump station

Gravity thickeners

Sludge drying beds

Decant pump station

Thickened sludge pump

station

Solids lagoons

Underdrain pump station

Solids diversion pump station


1-4 WT1010161153PDX

improvement project but was recently completed in 2016. Figure 1-3 shows when each major component of the JWC WTP were was completed.

In 2015, JWC completed a capital improvement program (CIP) update (Carollo Engineers, 2015), which presented a unified plan based on multiple previous studies and reports. The overarching concept for the CIP included plans for expanding the JWC WTP to 85 MGD around 2019.

Among the previous studies considered was the Seismic Hazard Mitigation Study of the JWC WTP (Carollo Engineers, 2008). This study defined the risks associated with the liquefiable soils at the site and identified the older facilities that do not have the capacity to withstand liquefaction. As a result, the JWC also plans to complete a major seismic resiliency project following the commissioning of the Willamette Water Supply Program, after 2026. This JWC seismic upgrade would assure a higher level of confidence that the WTP would be operational following a Cascadia subduction zone earthquake event. This upgrade would involve replacing or retrofitting vulnerable plant infrastructure.

This Facility Plan builds on the 2015 CIP update by further defining the future water treatment system and process improvements and solids handling at the JWC WTP while developing an approach to implement future improvements. This approach includes detailed plans for the current 2019 Expansion to 85 MGD Project and conceptual plans for both the Seismic Resiliency and Ultimate interim WTP Buildout expansion projects.

Figure 1-3. Joint Water Commission Water Treatment Plant Expansion History

1.3 Facility Planning Process The facility planning process was a collaborative effort between CH2M HILL Engineers, Inc. (CH2M) and the JWC partner staff. The process primarily consisted of a series of five workshops. Before the workshops, the JWC core team (WTP staff and project manager) and CH2M team worked together to develop alternatives presented to the JWC Technical Advisory Committee (TAC). Preferred alternatives were identified for further consideration. In the final workshop, the preferred alternatives were

LEGEND

1976 1986 1992

2000 2007 2016

Solids drying beds

Flocculation/ sedimentation

Backup generator

Filters



Operations building

Gravity thickeners

Surge basins

Clearwell

Caustic building

Basin G plate settlers

Sludge ponds


WT1010161153PDX 1-5

packaged together, considering the entire scope of the project and project budget, to identify the preferred facility planning concept.

The facility planning process was broken out into five segments corresponding to each of the five workshops. These were completed as follows:

• Workshop 1: Facility Plan Kickoff, Criteria, and Planning

• Workshop 2: Solids Handling, Dewatering, and Disposal

• Workshop 3: Spring Hill Pumping Plant and Raw Water Pumping and Conveyance

• Workshop 4: Treatment Process Alternatives

• Workshop 5: Plant Layout and Facility Plan Alternative Packaging

The information presented in this Facility Plan represents the culmination of the information presented in the workshops and the decision arrived upon by the JWC TAC as part of the facility planning process.

1.4 Acknowledgements The JWC facility planning process was completed as a highly collaborative effort. The following contributors deserve praise for their help in achieving the Facility Plan goals in a timely and effective manner. The results of this Facility Plan would not have been possible without the input of each contributor listed below.

JWC Staff:

• Kevin Hanway; JWC General Manager

• Erika Murphy, PE; JWC Project Manager

• Sophia Hobet; Water Operations Manager

• Chris Wilson; Assistant Water Manager/JWC WTP Manager

• Zac Bertz; JWC WTP Coordinator

JWC TAC:

• Alan Johansson, PE; City of Beaverton

• Brian Rigwood, City of Beaverton

• Dave Winship, PE, PLS, CWRE; City of Beaverton

• Derek Robbins, PE; City of Forest Grove

• Rich Blackmun, PE; City of Forest Grove

• Kristel Fesler, City of Hillsboro

• Nesh Mucibabic, PE; City of Hillsboro

• Niki Iverson, City of Hillsboro

• Tyler Wubbena, PE; City of Hillsboro

• Carrie Pak, PE; Tualatin Valley Water District

• Pete Boone, PE, PLS; Tualatin Valley Water District

CH2M:

• Brad Phelps, PE; CH2M Project Manager

• Kim Ervin, PE; CH2M Design Manager

• Tony Myers, PE; CH2M Senior Treatment Advisor

• David Oerke, PE; CH2M Senior Solids Advisor

• James Kapla, PE; CH2M Intake Advisor

• Enoch Nicholson, PE; CH2M Process Lead

• Joshua Kennedy, PE; CH2M Project Engineer

• Theresa Ring, CH2M Project Engineer

SECTION 2

WT1010161153PDX 2-1

2Planning Criteria

2.1 Water Source and Available Supply

2.1.1 Current Water Rights The current water supply for the JWC WTP comes primarily from the Tualatin River and its tributaries and is supplemented by stored water in Hagg Lake/Scoggins Dam and Barney Reservoir/Mills Dam as shown on Figure 2-1. Throughout the year, the contribution each source makes to the raw water supply changes due to available water in the Tualatin River basin and limitations provided in the JWC water rights. Based on current JWC water rights, JWC can withdraw up to 125.6 MGD from the Tualatin River during winter months, as long as a natural flow of 40 cubic feet per second (cfs) remains at the river gauge at Golf Course Road just downstream of the JWC raw water intake. When natural flow drops below 40 cfs (26.8 MGD), regulation of water rights limits the amount of natural flow available from the river. Depending on the river level, the JWC system is limited to an intake flow between 0 and 14 cfs (9 MGD) without releasing stored water from Hagg Lake and/or Barney Reservoir. As the river levels change through the summer, the amount of natural flow available to the JWC may fluctuate between 0 and 14 cfs (9 MGD).

The US Bureau of Reclamation owns Hagg Lake, which is impounded by the Scoggins Dam. Planning is currently underway to replace or renovate Scoggins Dam to meet current seismic design standards. During the summer up to 13,500 acre-feet (4,400 million gallons [MG]) of water is available from Hagg Lake for JWC use in two different water rights certificates. The existing water right for 13,000 acre-feet (4,237 MG) of water under JWC has a release rate limit of 45.2 MGD. The City of Hillsboro also has an additional 500 acre-feet (163 MG) of stored water in Hagg Lake that does not have a release rate limitation.

Barney Reservoir is managed by the Barney Reservoir Joint Operating Committee that consists of the City of Hillsboro, City of Forest Grove, City of Beaverton, and the Tualatin Valley Water District, as well as Clean Water Services (CWS). Up to 14,886 acre-feet (4,850 MG) of water is available to JWC from Barney Reservoir. Similar to Hagg Lake, the release rate is also limited, although by both water rights and infrastructure capacity. Together, JWC and CWS can release 44.4 MGD from Barney Reservoir. Officially, JWC is limited to 25 MGD but historically has cooperated with CWS to use the full release capacity of the infrastructure when CWS does not need water for their use. JWC has started the process to officially increase the JWC maximum release rate to 44.4 MGD. Even when sharing the outlet capacity, the volumetric total released from Barney Reservoir each year has not been exceeded. This joint use of the outlet infrastructure has worked well since JWC typically needs

Figure 2-1. Joint Water Commission Water Sources

SECTION 2 – PLANNING CRITERIA

2-2 WT1010161153PDX

additional flow during peak water demand periods in July and August while CWS needs more flow in the early fall.

Forest Grove has 414 acre-feet (135 MG) of stored water in Barney Reservoir that does not have a release rate limitation. The rates and tables below do not call this out because the maximum release rate of 44.4 MGD is limited due to the reservoir outlet infrastructure. The JWC’s available water rights are summarized in Table 2-1. Details of the individual water rights are provided in Table 2-2 and Table 2-3.

Based on the acceptable release rates for JWC and assuming thatRaw water supplies are sufficient to supply an expanded WTP capacity of 85 mgd. After approval to use the full capacity of Barney Reservoir infrastructure, raw water supplies can also support the interim expansion to 105 mgd. If natural flow is not available from the Tualatin River, up to 70 MGD can be obtainedthe JWC has water supplies to produce 70.2 MGD for 107 days and 85 MGD for 20 days. However, if natural flow of 14 cfs (9 MGD) is available from the river, and JWC obtains approval to fully utilize the Barney Reservoir infrastructure, and has access to CWS’s unused share of the Barney Reservoir release rate, up to 98.6 MGD can be obtainedthe JWC has water supplies to produce 98.6 MGD for 75 days and 105 MGD for 25 days. The stored water with an associated release rate could support that demand for 94 days. In addition, 163 MG (City of Hillsboro’s water right) is available from Hagg Lake to supplement the maximum rate for a limited duration during peak demands. Assuming that the peak demand period could lasts for up to 21 days, this additional release could provide 6.3 MGD available for a peak raw water diversion of 105 MGD. This would support a 115-day release season, which was the shortest release season between 2002 and 2016. Note that 1 to 3 percent more water will be required to produce a finished water capacity of 105 MGD. This value forms the basis for the currently assumed ultimate buildoutinterim expansion peak raw water diversion of the JWC WTP. This analysis assumes that leasing stored water among the partners perfectly matches supplies to demands. It also assumes that the release rate from storage perfectly matches demand and that all of the released water is captured at the WTP.

A determination of ultimate buildoutinterim expansion capacity is important to the Expansion to 85 MGD project as it informs the general placement of future structures. A more detailed analysis of supply and demands can be performed included in a future Facility Plan or Master Plan.

Table 2-1. Joint Water Commission Water Rights Summary

Source

Non-Peak Season River Flow (more than 40 cfs river flow)

Peak Season River Flow (less than 40 cfs river flow)

Volumetric Water Rights (MG)

Maximum Rate (MGD)

Volumetric Water Rights

(MG)

Minimum Permitted Rate

(MGD)

Maximum Permitted Rate

(MGD)

Tualatin River natural flow N/A 125.6 N/A 0a 9a

Hagg Lake N/A N/A 4,237

163

45.2

N/Ab

45.2

N/Ab

Barney Reservoir N/A N/A 4,715

135

25

N/Ab

44.4c

N/Ab

Total N/A 125.6 9,250 70.2d 98.6d

a Permitted rate varies based on river flow.

b There is no release rate limitation on this volume.

c Includes Clean Water Services’ release rate when otherwise not in use. d These values under-represent available supply because not all water rights for stored water include a permitted rate.

Notes:

cfs cubic feet per second MG million gallons MGD million gallons per day N/A not applicable


WT1010161153PDX 2-3

Table 2-2. Nonpeak Season Joint Water Commission Municipal Water Rights Available at Joint Water Commission Water Treatment Plant

Source Priority Date

Application

Permit

Certificate

Transfer Entity Name on

Water Right

Authorized Rate

cfs MGD

Sain Creek 1/22/1912 A: S-2016 P: S-1136

81026 City of Hillsboro 3.00 1.94

Sain Creek 5/1/1915 A: S-4250 P: S-2443


Tualatin River 8/15/1930 A: S-13681 P: S-10408





85914 City of Beaverton

25.00 16.15


85916 City of Forest Grove

33.00 21.32

Scoggins Creek 6/9/1988 A: S-69637

P: S-50879 P: S-54737

T-11155 Joint Water Commission

75.00a 48.45

Gales Creek 2/14/1947 A: S-22251

P: S-17549

85513

T-11677

City of Forest Grove

4.46 2.88

Total Maximum Authorized Rate 194.46 125.62

a The JWC received access to only a 26 cfs portion of this rate through its 2010 WMCP.

Notes:

cfs cubic feet per second JWC Joint Water Commission MGD million gallons per day WMCP Water Management and Conservation Plan WTP water treatment plant

Table 2-3. Peak Season Joint Water Commission Municipal Water Rights Available at Joint Water Commission Water Treatment Plant

Source Priority

Date Application

Permit Certificate Transfer Entity Name on Water Right

Authorized Rate Authorized

Volume, acre-feet cfs MGD

Sain Creek 1/22/1912 A: S-2016 P: S-1136

81026 City of Hillsboro 3.00 1.94 N/A

Sain Creek 5/1/1915 A: S-4250 P: S-2443




Middle Fork of the North Fork Trask River and

Barney Reservoir

6/26/1958 A: S-32421 P: S-32139

81020 Barney Reservoir IGA: Hillsboro – 5,127 acre-feet

Beaverton – 3,556 acre-feet

TVWD – 5,789 acre-feet

38.70 25.0 14,472a


2-4 WT1010161153PDX

Table 2-3. Peak Season Joint Water Commission Municipal Water Rights Available at Joint Water Commission Water Treatment Plant

Source Priority

Date Application

Permit Certificate Transfer Entity Name on Water Right

Authorized Rate Authorized

Volume, acre-feet cfs MGD

Scoggins Reservoir

2/20/1963 A: S-38447 P: S-35792

87304 Bureau of Reclamation Contracts:

Hillsboro - 4,500 acre-feet Forest Grove - 4,500 acre-feet Beaverton – 4,000 acre-feet

70.00 45.22 13,000

Barney Reservoir 6/24/1971 A: S-48359 P: S-37837

81022 City of Forest Grove N/A N/A 414a

Scoggins Reservoir

2/20/1963 A: S-38447 P: S-35792

87303

T-11872

Bureau of Reclamation (Hillsboro contract)

N/A N/A 500

Maximum Authorized Rate/Volume of All Water Rights 122.7 79.26 28,386

Notes: ab The total volume of Barney Reservoir is 20,000 ac-ft. Storage amounts for Clean Water Services and Oregon Department of Fish and Wildlife are not presented.

cfs cubic feet per second JWC Joint Water Commission MGD million gallons per day N/A not applicable

TVWD Tualatin Valley Water District WTP water treatment plant

2.1.2 Future Sources of Supply If the status of water rights or water supply availability changes, the effects will be outlined in future Facility and Master Plans, and will inform Commission decision-making on water treatment plant expansions. Future planning efforts will include a more detailed analysis of ASR development and available supply and treatment capacity.

2.2 Water Quality Goals The primary water quality goals for the JWC WTP are to comply with all existing and proposed state and federal regulations. In addition to primary and secondary drinking water standards as promulgated by the U.S. Environmental Protection Agency, the JWC WTP also holds to the following more stringent operational water quality goals:

• Filtration performance—JWC targets a turbidity goal of less than 0.12 nephelometric turbidity unit (NTU) in the filter effluent. Less than the U.S. Environmental Protection Agency regulation of 0.3 NTU 95 percent of the time and 1 NTU 100 percent of the time.

• Aesthetics—JWC strives to provide aesthetically pleasing water to their customers, in both appearance and taste and odor. Historically, JWC has had periodic taste and odor challenges resulting from unusual raw water quality with greater organic content, primarily from Wapato Lake. However, through careful research and understanding of the water supply, JWC has been able to introduce management practices and treatment to meet the aesthetic water quality goals.

• Future regulations—JWC will continue to position for compliance with future water quality regulations as they are developed. The most likely future regulations that might impact JWC identified by the project team and the TAC are related to contaminants of emerging concern (primarily pesticides and herbicides resulting from upstream agriculture), and more stringent or additional regulations regarding disinfection byproducts.


WT1010161153PDX 2-5

2.3 Partner Demand Projections Each of the four JWC partners have varying projections for future water use from the JWC WTP. As shown in Table 2-4, TVWD is currently using its full WTP capacity. Hillsboro projects to reach full use of WTP ownership capacity in 2022. Forest Grove projects full use in 2047, and Beaverton projects full use in 2048.

Table 2-4. Joint Water Commission Partner Demand Projections

Partner Full JWC WTP Utilization Year

Tualatin Valley Water District Now

City of Hillsboro 2022

City of Forest Grove 2047

City of Beaverton 2048

Notes:

JWC Joint Water Commission WTP water treatment plant

Based on these projections, the WTP expansion to 85 MGD is required to provide adequate water to Hillsboro and TVWD prior to the completion of the Willamette Water Supply Project in 2026. Additional treatment capacity beyond the current expansion is not expected to be needed prior to 2047 as indicated by the Forest Grove and Beaverton demand projections. Partner demand projections through year 2050 are shown in Figure 2-2. Note that TVWD maximum day demand exceeds the TVWD ownership in the JWC WTP. This excess demand is currently being met through leased treatment capacity. Hillsboro’s projected maximum day demands exceed their WTP ownership capacity between 2022 and 2026. During this period, Hillsboro intends towill lease WTP capacity from other JWC partners until the commissioning of the Willamette Supply.

Future JWC master planning will consider peak capacity demands beyond 2050 and project winter capacity needs.

Figure 2-2. Joint Water Commission Water Treatment Plant Maximum Day Demand by Partner

0

10

20

30

40

50

60

70

80

90

100

2014 2018 2022 2026 2030 2034 2038 2042 2046 2050

JWC

WTP

Max

imu

m D

ay

Dem

and

(M

GD

)

TVWD Forest Grove Beaverton Hillsboro


2-6 WT1010161153PDX

2.4 Joint Water Commission Water Treatment Plant Capacity Goal Definitions

JWC has defined capacity goals that are specific to the JWC WTP. These capacity goals are defined as follows, per the 2015 CIP update (Carollo Engineers, 2015):

• Peak capacity—Production rate that can be sustained for at least 3 days with all units in service under typical summertime raw water conditions.

• Firm capacity—Production rate that can be sustained for at least 3 days with the single largest pump or filter out of service in a system under typical summertime raw water conditions.

• Sustained winter capacity—Maximum production rate that can be sustained at least 80 percent of the time during the nonpeak season (November through April) with all units in operation.

The JWC WTP capacity goals are sized around maximum day demands and being able to meet those demands with the WTP Peak Capacity. Sizing WTPs for maximum day demand is the standard practice in the drinking water industry because water system storage is usually only capable of equalizing demands over a day or a few days and as such the WTP must be able to supply the maximum day demand.

2.5 Seismic Level of Service Goals The JWC established minimum level of service (LOS) goals for the JWC WTP as part of the JWC Seismic Hazard Evaluation--Fern Hill WTP (Shannon & Wilson, 2008). Table 2-5 is directly from the 2015 CIP update (Carollo Engineers, 2015) and shows the LOS goals established by JWC. These goals were reviewed as part of the Facility Plan process in coordination with the improvements required to meet them. Although the LOS goals could be met with only partial replacement of the facilitiesDuring the Facility Plan process, the JWC determined that full mitigation or replacement is more consistent with the planned expansion and continuous operation of the WTP. Therefore, the proposed partial upgrades in the 2015 CIP proposed partial upgrades are updated in this Facility Plan for full upgrades or replacement

as needed for were updated in this Facility Plan to a site-wide replacement of facilities to assure a seismically resilient 85-MGD facility.

Table 2-5. Level of Service Goals Following Seismic Event

Seismic Events Immediate Capacity

(MGD) Short-Term Capacity

(MGD) Short-Term Restoration Time

(Days) Water Quality

72-year event 42a 42a 0 Potable

475-year eventb 0 24 1 Potable

2,475-year event 0

12 3

Potable 28c 7 to 14

42a 60 to 90

a Average day demand is 42 MGD.

b Also referred to as the Cascadia Subduction Zone event.

c Average winter demand is 28 MGD.

Note:

MGD million gallons per day


WT1010161153PDX 2-7

2.6 Joint Water Commission Planning Schedule and Milestones

Based on partner demand projections and coordination with other planned water supply projects, the JWC TAC developed the following planning milestones and proposed plant improvements in three four phases.

2.6.1 Expansion to 85 Million Gallons per Day The current Expansion to 85 MGD Project includes four major components:

• Resolve limitations to achieve the currently rated plant peak capacity of 75 MGD.

• Expand the WTP to achieve 85-MGD peak capacity.

• Complete previously planned CIMP projects.

• Implement seismic life safety projects.

The improvements to get to 75 MGD, CIMP, and seismic life safety elements will have financial participation by all partners based on their respective current shares in the WTP peak capacity. The 10 MGD expansion from 75 to 85 MGD is being paid for by Hillsboro and TVWD and will increase their respective ownership shares of the WTP. This project is scheduled to be completed by June 2019, to meet increased water demands.

2.6.2 Seismic Resiliency Project The Seismic Resiliency Project is planned to address significant seismic concerns related to the WTP’s ability to meet the LOS goals stated above in Table 2-56. The 2008 Seismic Hazard Evaluation of the WTP revealed that the soil at the WTP site is subject to liquefaction under the 475-year and 2,475-year seismic events. The older facilities at the plant were not built with ground improvements or foundations for this type of soil and will likely not withstand the differential settlement and lateral spread resulting from liquefaction. Therefore, many of the facilities were identified for foundation improvements or replacement.

The original project described in the 2008 Seismic Evaluation (Carollo, 2008) included replacing or upgrading facilities to provide the post-seismic event LOS goal of 42 MGD of potable water. Subsequent work that has been completed since the initial development of the LOS goals has invalidated that assumption. The 2015 CIP determined that, with limited exceptions (four sedimentation basins), it is either not technically or operationally feasible to construct upgrades to the existing WTP facilities to make them capable of surviving anticipated earthquake events. To achieve production capacity goals after an earthquake, the 2015 CIP instead recommended the replacement of, rather than upgrades to, the remaining WTP facilities. The facility planning activity proceeded on the assumption that all new facilities identified for construction in the Facility Plan would be built to current standards, which includes construction to seismic standards that will be current as of the time of construction. The ability of the WTP to provide 85 MGD of resilient capacity after construction of those improvements is an outcome of that assumption. Further project details are described in Section 7. This project is currently scheduled to be completed after the Willamette Water Supply Project becomes operational, which is scheduled to occur in 2026.

2.6.3 Ultimate Interim WTP Capacity Expansion ProjectBuildout Based on the available water rights for the partners at the JWC facility, the ultimate interim plant expansion peak capacity is expected to be 105 MGD. The timeline of the ultimate plant buildoutinterim expansion is currently undefined. Based on the partner demand projections included above, interim plant buildout expansion likely will not occur until after 2040. In addition to developing ultimate interim plant treatment capacity, the ultimate interim expansion plant planning process included evaluating


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potential future treatment processes to address changing source water quality or regulations. See Section 8 for further detail.

2.6.4 Future Expansion Project The future expansion project is planned to increase winter capacity for the JWC partners. Based on the available winter water rights for the partners at the JWC facility, future expansion capacity is expected to be approximately 130 MGD. The timeline of the future expansion is currently undefined. The future plant expansion planning process included a brief evaluation of treatment processes required to achieve 130 MGD winter capacity. See Section 9 for further detail.

SECTION 3

WT1010161153PDX 3-1

3Seismic Improvements Plan

3.1 Previous Seismic Analysis Work The primary seismic analysis of the JWC WTP was conducted as part of the 2008 Seismic Mitigation Study and described in JWC Seismic Hazard Evaluation—Fern Hill WTP (Shannon & Wilson, 2008). The results of this study were reevaluated in accordance with more recent design and building codes as part of the Revised Geotechnical Report—JWC WTP Seismic Evaluation (Shannon & Wilson, 2014). The updated review of the seismic hazard evaluation completed in 2014 also evaluated constructability of the proposed seismic resiliency project elements, attempting in-situ ground and foundation improvements. A constructability review resulted in some significant changes to the seismic resiliency plan as described in the 2015 CIP update (Carollo Engineers, 2015). This Facility Plan did not analyze the previous seismic analysis work and relied on this previous work as the basis for facility planning.

3.2 Life Safety Mitigation Approach The Joint Water Commission Water Treatment Plant Seismic Evaluation Final Report (Carollo Engineers, 2008) identified several recommended life safety improvements based on a goal of protecting life safety for the 475-year return-period earthquake scenario. As part of the 2015 CIP Update (Carollo Engineers, 2015), the JWC decided to proceed with only the life safety mitigation portion of the seismic work in the first 2019 project and defer other improvements to the next project after 2026. Based on results of the seismic constructability review included in the 2015 CIP Update, several major life safety mitigation project elements were deemed not feasible and were removed from the Facility Plan. Table 3-1 compares the life safety improvements proposed in the 2015 CIP update and those that are to be included in the 2019 Expansion to 85 MGD Project. An evaluation of the improvements is also discussed in Appendix D.

Table 3-1. Comparison of Life Safety Improvements Included in 2015 Capital Improvement Program Update and 2016 Facility Plan

Facility 2015 CIP Update

2016 Facility Plan (Expansion to 85

MGD) Notes

Raw water pump station (SHPP): structural ✓ Deferred due to permitting and cost share uncertainty.

Raw water pump station (SHPP): nonstructural—restrain electrical and storage cabinets

✓ ✓

Raw water pump station (SHPP): nonstructural—install temporary pump facility

✓ Deferred due to budget constraints

Rapid mix facility: nonstructural—restrain grating ✓ ✓

Flocculation/sedimentation basins: structural—baffle support strengthening

✓

Flocculation/sedimentation basins: nonstructural—improve basin G plate support

✓ ✓

Filters: nonstructural—restrain HVAC equipment ✓ ✓

FWPS 1: nonstructural—restrain HVAC and electrical equipment

✓ ✓

SECTION 3 – SEISMIC IMPROVEMENTS PLAN

3-2 WT1010161153PDX

Table 3-1. Comparison of Life Safety Improvements Included in 2015 Capital Improvement Program Update and 2016 Facility Plan

Facility 2015 CIP Update

2016 Facility Plan (Expansion to 85

MGD) Notes

FWPS 2: structural—strengthen pier wall ✓ ✓

FWPS 2: nonstructural—restrain electrical and storage cabinets

✓ ✓

FWPS 2: nonstructural—make electrical and piping improvements

✓

Operations building: structural—make building improvements

✓ ✓ Structural strengthening included. Foundation improvements not included, building to be replaced.

Operations building: nonstructural—brace cabinets and tanks

✓ ✓

General and site: nonstructural—brace electrical equipment in 1998 MCC/Generator building

✓ ✓

General and site: nonstructural—brace tanks in sodium hydroxide building

✓ ✓

Notes:

CIP capital improvement program FWPS finished water pump station HVAC heating, ventilation, and air conditioning MCC motor control center MGD million gallons per day SHPP Spring Hill Pumping Plant

3.3 Water Treatment Plant Seismic Resiliency Approach After completing the constructability review in the 2015 CIP update, the JWC determined that most facilities on the site would need to be replaced to be seismically resilient. Table 3-2 shows the proposed approach from the 2015 CIP update (Carollo Engineers, 2015), along with recommended considerations for revisions to this plan that would allow JWC to achieve the established seismic LOS goals. These projects are deferred until after 2026.

Table 3-2. Proposed Seismic Resiliency Approach for 85 Million Gallons per Day Post-Seismic Capacity

Facility Replace Rehabilitate

Existing

Currently Meets LOS Goal—No Further Activity Planned Notes

Raw water pump station (SHPP)

✓ An analysis is also being performed to consider replacement of the SHPP.

Raw water pipelines ✓

Rapid-mix facility ✓

Flocculation/ sedimentation basins A through C

✓ Additional resilient capacity could also be achieved by adding flocculation time and additional plates to the existing basins D through G.

SECTION 3 – SEISMIC IMPROVEMENTS PLAN

WT1010161153PDX 3-3

Table 3-2. Proposed Seismic Resiliency Approach for 85 Million Gallons per Day Post-Seismic Capacity

Facility Replace Rehabilitate

Existing

Currently Meets LOS Goal—No Further Activity Planned Notes

Flocculation/ sedimentation basins D through G

✓

Settled water flume ✓ Parallel pipe to be installed to new filters with connection to existing filters as part of the 2019 Expansion to 85 MGD Project.

Filters 1 through 14 ✓ Two new 924-square-foot filters being constructed as part of the 2019 Expansion to 85 MGD Project. Four filters (total) will be required to meet established LOS goals (42 MGD). Eight filters will be required for complete filter facility replacement (85 MGD).

Clearwell ✓ Clearwell could be configured with bypass to FWPS 2 and use Fern Hill Reservoirs for CT.

FWPS 1 ✓ Replacement required to meet 85-MGD seismic resilience.

FWPS 2 ✓

Operations and chemical building

✓ Building planned for replacement with two separate structures.

Old generator MCC building for sedimentation basins D-G

✓

New 5-MW backup generator building

✓

Surge basins ✓ New surge basin (50 percent of required capacity) being constructed as part of 2019 Expansion to 85 MGD Project.

Gravity thickeners N/A Gravity thickening being removed from solids handling system.

Solids drying beds ✓ Two new solids drying beds are being constructed as part of the 2019 Expansion to 85 MGD Project.

Sludge Ponds N/A Sludge ponds being removed from solids handling system.

Notes:

✓ = Planned mitigation approach. CT [chlorine concentration x] contact time FWPS finished water pump station LOS level of service MCC motor control center MGD million gallons per day MW megawatt N/A not applicable SHPP Spring Hill Pumping Plant

SECTION 4

WT1010161153PDX 4-1

4Plant Capacity Summary

4.1 Hydraulic Analysis Hydraulic modeling was completed as part of the facility planning process to aid in accomplishing the following:

• Identifying existing hydraulic bottlenecks and component hydraulic capacities

• Evaluating alternatives to mitigate hydraulic constraints

• Modeling the future (2019) WTP improvements to develop a revised hydraulic profile for the WTP

Most of the hydraulic analysis was completed using CH2M’s proprietary Replica dynamic simulation software. This software allows users to integrate the hydraulics and controls of a given process and examine facility operation with varying flow inputs and operational strategies. The current modeling effort produced a steady state model of the JWC WTP; however, the current model could be enhanced to allow for future dynamic simulation to evaluate plant control components or other operational optimization. The data input for the hydraulic model consisted primarily of information from historical construction drawings, water surface measurements from the 2012 plant expansion preliminary design (Carollo Engineers, 2012), and photographs and descriptions of plant elements, all provided by JWC staff.

In addition to the Replica modeling, computational fluid dynamic (CFD) modeling of the Spring Hill Pumping Plant (SHPP) was completed to evaluate concerns regarding differences between the rated and measured capacity of the SHPP raw water pumps. This evaluation concluded that the existing intake bay for the four pumps is likely exhibiting submerged vortexing at maximum flow with all pumps operational, especially when river sediment buildup occurs in the forebay. Additional field testing in combination with cleaning the forebay did not show significant change in the pump station capacity. The detailed summary of the hydraulic modeling effort is included in the JWC WTP Facility Plan Hydraulic Analysis Report included in Appendix B.

4.2 Unit Process Capacity Summary The project team reviewed the plant unit process capacities from previous projects and updated their capacities based on recent field data or additional analysis. In summary, the backwash waste system is the current limiting factor for peak capacity. This is followed closely by the rapid mix, filtration, flocculation/sedimentation basin, and solids drying bed capacities. The results are summarized in Table 4-1.

4.3 Winter Sustained Capacity Winter sustained capacity is defined as the maximum production capacity that can be sustained at least 80 percent of the time during the nonpeak season with all units in operation. Winter sustained capacity was not evaluated as part of the facility planning process. Previous evaluation from the 2015 CIP Update (Carollo Engineers, 2015) and 2012 Plant Expansion Preliminary Design (Carollo Engineers, 2012) showed that the primary limiting factors for winter sustained capacity were the waste washwater handling system, flocculation and sedimentation basin, and filtration system.

SECTION 4 – PLANT CAPACITY SUMMARY

4-2 WT1010161153PDX

Table 4-1. Existing Unit Process Capacity

Facility/Process

Existing Capacity in MGD (2016)

Peaka Firmb Post-Seismic Eventc

Goal for 2019 Expansion to 85 MGD Project 85

Raw water delivery (SHPP and raw water pipelines)

81.3d Approximately 61e 0

Rapid mix facility and flow split 70 70 0

Flocculation/sedimentation basins 75 75 45f

Filtration, net capacity 72 66 0

Settled water conveyance 80 80 0

Disinfection and clearwell 85 or more g 85 or moreg 0

Finished water pump stations 87h 73h 0i

Backwash waste (surge basins and recycle pumps) 68j 68j 0

Solids drying beds 75 75 75

a Peak capacity is defined by JWC as the summer capacity that can be sustained for a minimum of three days with all units in service. b Firm capacity is defined by JWC as the summer capacity that can be sustained with the largest pump or filter in a system out of service.

c Seismic vulnerability of facilities taken from the 2015 CIP Update (Carollo Engineers, 2015) and 2008 Seismic Hazard Mitigation Study (Carollo Engineers, 2008) for the 475-year and greater earthquakes. No seismic analysis was performed as part of this facility planning process.

d Based on outcome of full-scale testing conducted in November 2016 and calibrated hydraulic model. Flow data based on new raw water flow meters install in October and November 2016.

e From 2012 Plant Expansion Preliminary Design (Carollo Engineers, 2012). Based on nameplate capacity. f Based on loss of basins A through C. g Based on theoretical modeling completed as part of this 2016 facility planning process. Assumes pH of 8.0, Cl2 residual of 0.9 mg/L, water temperature of 12.5 °C, and clearwell baffling factor (T/T10) of 0.6. Takes credit for 21 minutes of CT in pipeline to WTP operations building (first customer). Higher flows are possible, but actual capacity will vary significantly depending on information not available at this time such as assumed flow split to each pump station and to each of the finished water pipelines.

h From 2012 Plant Expansion Preliminary Design (Carollo Engineers, 2012). Based on testing performed in June 2011 and evaluation of pump curves.

i Based on loss of FWPSs 1 and 2 due to liquefaction. j Based on summer 2015 operational data.

Notes:

°C degrees Celsius CIP capital improvement program Cl2 chlorine

CT chlorine concentration (C) x contact time (T) FWPS finished water pump station JWC Joint Water Commission MGD million gallons per day mg/L milligrams per liter SHPP Spring Hill Pumping Plant TBD to be determined WTP water treatment plant

SECTION 5

WT1010161153PDX 5-1

5Facility Evaluation and Alternative Selection This section addresses the evaluation of alternatives considered to meet the project objectives of the plant expansion to 85 MGD and related improvements. The project includes the following objectives:

• Remove hydraulic bottlenecks in the existing WTP to provide a reliable 75-MGD peak capacity for all JWC Partners.



• Complete previously identified CIMP.

The following sections describe the selected major plant improvements. The full evaluation of alternatives is provided in Appendix A. The packaged 2019 Expansion to 85 MGD Project is described in Section 6.

The alternative selection process was conducted during workshops with representatives from each JWC partner present. The primary factors that influenced the final decisions were as follows:

• Achieving the established plant peak capacity goals

• Maintaining the established project budget

• Limiting unnecessary operational complexity

• Minimizing stranded costs.

The alternatives selected by the JWC represent those that best meet these goals.

5.1 Supply and Treatment Processes

5.1.1 Required Treatment Capacity and Water Loss To deliver a peak capacity of 85 MGD (current project), or 105 MGD (ultimate interim expansionbuildout), or 130 MGD (future expansion) of finished water to the transmission system, the processes upstream of filtration (raw water pumping, rapid mix, and flocculation/sedimentation) will need to be able to produce more than the required finished water demand to account for water losses through the WTP. A WTP can expect to lose about 1 to 3 percent of the water treated through sedimentation basin blowdown, backwashing, and plant utility water. This means that JWC should assume towill need 88, and 108, and 135 MGD for 2019, and ultimate buildoutinterim expansion, and future expansion, respectively, at the rapid mix facility to produce 85, and 105, and 130 MGD at the entry point to the transmission system. At JWC, most water lost from the sedimentation basins and backwash system is recycled. This results in a raw water diversion rate that is lower than the rest of the required treatment processes, but still greater than 85 or 105 MGD. This additional raw water diversion is required to make up water lost to plant utility water and evaporation and infiltration in the solids handling system. Figure 5-1 shows the various locations where water is diverted from the process stream and potentially lost in the treatment process.

SECTION 5 – FACILITY EVALUATION AND ALTERNATIVE SELECTION

5-2 WT1010161153PDX

Figure 5-1. Water Loss and Recycling Schematic

5.1.2 Raw Water Intake and Pumping The SHPP is located on the Tualatin River and shares the intake and raw water pumping structure with the Tualatin Valley Irrigation District. The JWC owns and operates four pumps in the SHPP facility, but past analyses have shown that the pumps do not achieve their full nameplate capacity. The Water Treatment Plant Expansion Preliminary Design Project (Carollo Engineers, 2012) listed the theoretical capacity as 89 MGD based on pump and system curves, with a maximum flow of 77.5 MGD based on pumping tests after correcting for flow meter inaccuracy. The existing SHPP is shown in Figure 5-2.

CFD and hydraulic modeling were completed as part of the hydraulic analysis, as described in Section 4.1, to determine the reason for the shortfall in pumping capacity. Following the CFD analysis, two short duration pumping tests were conducted in June 2016 to verify the pumping capacity. The two tests were performed by operating two pumps during each test and then adding the test results together. The result was a combined capacity of 89.9 MGD with a water level of 11.7 feet in the wetwell and a cleaned intake. However, the increased system headloss with all four pumps running simultaneously will result in a lower pumping capacity. Additional testing was conducted in August 2016 with all four pumps in service. This test was conducted with a water level of 11.2 feet in the wetwell. The results of this test showed that the raw water pump system was capable of producing 77.9 MGD (after flow meter correction of +6 percent).

Follow up testing conducted in November 2016 after installation of new flow meters was used to calibrate the system hydraulic model and resulted in a raw water capacity of 81.3 MGD. Data from these four pump tests as well as other operating data collected by JWC will be used to size the four new raw water pumps. Note that the design water level is 11.5 feet and the actual minimum level is approximately 8.8 feet minus headloss through the intake screens, which corresponds to an elevation of 142.8 feet. At water levels below 145.5 feet (11.5 feet intake level) the pump performance will decrease below the design value and result in raw water pump flow rates below the design values.


WT1010161153PDX 5-3

Figure 5-2. Spring Hill Pumping Plant Profile

Following the tests, the SHPP electrical infrastructure capacity was evaluated to identify which pumps need to be replaced to increase pumping capacity to 88 MGD without requiring electrical upgrades. Based on this electrical evaluation it was determined that all four pumps can be upgraded to 400 horsepower (hp) to maximize the existing electrical infrastructure capacity.

An additional evaluation is being conducted to determine whether vortex issues are occurring with the existing SHPP wetwell. “Spider” straightening vanes are currently planned on the intake of each of the four raw water pumps to correct for vortex issues if they are confirmed to be problematic.

The existing SHPP intake structure includes bar screens and traveling fish screens designed and constructed under earlier guidance and regulations. The fish screen’s opening size, lack of sweeping velocity, and impingement velocity will not comply with current regulations, although the evaluation of this system indicates that it can pass a larger volume of water, up to the currently planned 88 MGD. In the future, replacing or supplementing the JWC raw water pump station is expected to be required for the following reasons: compliance with seismic resiliency goals; adherence to fish screen regulations; and increased demand and the need for additional pumping capacity. Since the SHPP is a shared facility with the Reclamation/Tualatin Valley Irrigation District, future improvements are still under consideration, although any building improvements (such as seismic improvements) would require a shared financial responsibility, and although the JWC may desire to make improvements, the co-owner may not.

In addition to improvements on the existing facility, JWC has, and continues to evaluate other alternatives including a new raw water pump station on the main stem of the Tualatin River and/or a new raw water pipeline from Scoggins Dam. Procuring land for a future raw water pump station is recommended so that it would be available as needed for the Seismic Resiliency Upgrades or for the ultimate plant buildoutinterim expansion project. Alternatively, JWC may opt to construct a pipeline to the WTP from Scoggins Dam on Hagg Lake in conjunction with a new raw water intake. JWC currently owns easements for much of the required pipeline route and may be able to coordinate a dam outlet

Traveling water screen

Raw water pump

Minimum water surface of 142.8 feet

To raw water pipeline


5-4 WT1010161153PDX

structure as part of a planned future rehabilitation/replacement project on the dam. JWC will continue to monitor and consider these alternatives into the future.

5.1.3 Raw Water Pipeline The existing transmission pipelines, one 36-inch and one 42-inch, convey water from the SHPP to the rapid mix facility as shown in Figure 5-3. JWC evaluated the headloss to confirm the conveyance capacity of these pipelines and found that no unusual conditions limit the expected capacity. The existing pipelines are sufficient for the expansion to 85 MGD to convey 88 MGD raw water, pending the increase in raw water pump capacity. However, the two pipelines will need to be improved or replaced to meet the seismic LOS goals. The transmission pipelines may also need to be upsized or paralleled to achieve the ultimate interim and future expansion capacity if the full supply is to be pumped from the existing SHPP.

Figure 5-3. Approximate location of the Raw Water Pipelines in relation to the Spring Hill Pumping Plant and Rapid Mix Facilities

Rapid mix facility



WT1010161153PDX 5-5

5.1.4 Rapid Mix Facility The rapid mix facility combines a weir-based flow-splitting system with open-basin jet injection for chemical mixing. The basin delivers water to three flow paths for seven flocculation/sedimentation basins. To allow the WTP to produce 85 MGD of finished water, the rapid mix facility must treat at least 88 MGD of raw and recycled water. A hydraulic model was developed to analyze the existing system’s capacity and confirm that each alternative could meet the capacity goal of 88 MGD, while providing for the required flow-control and flow-splitting capabilities. Additionally, the 2015 CIP update (Carollo Engineers, 2015) determined that the existing rapid mix facility needs to be replaced due to seismic vulnerability; therefore, the final goal was to limit the stranded costs associated with upgrading the facility.

The analysis of the existing rapid mix facility showed that removing the fiberglass baffle wall and relocating the jet injection point will be required to achieve the currently rated plant capacity of 75 MGD while preserving the recommended 1 foot of freeboard within the rapid mix.

Hydraulic modeling also showed that removing the wall and weir gates serving basins D through G would be required to achieve 88-MGD peak flow. These alternatives were compared with the construction of a new rapid mix facility, which would eliminate stranded cost and provide optimal flow control. Ultimately, JWC deemed constructing the new facility as part of the 2019 Expansion to 85 MGD Project cost-prohibitive during the Facility Plan workshops.

The selected alternative, shown in Figure 5-4, combines cost-effective modifications to the existing rapid mix with the installation of new flow meters and a flow-control valve to meet the design goals. By choosing to modify the existing structure, the cost of constructing a new rapid mix was deferred to the 2026 Seismic Resiliency Project, where it could be sized for ultimate buildoutinterim and future expansions and provide flow splitting to the new flocculation/sedimentation basins.

Figure 5-4. Selected Rapid Mix Alternative

5.1.5 Flocculation and Sedimentation The flocculation/sedimentation basin system consists of three older basins (A through C) and four newer basins (D through G). Basins A through C have two stages of flocculation, and basins D through G have


5-6 WT1010161153PDX

three stages of flocculation, each followed by sedimentation with mechanical sludge collectors. Plate settlers were installed in basin G in 2007 for performance comparison. The old basins were previously evaluated and identified as seismically deficient as part of the JWC WTP seismic evaluation (Carollo Engineers, 2008).

The flocculation and sedimentation basins were evaluated based on historical data and typical design criteria. Based on full-scale testing conducted by JWC during previous projects, a flocculation detention time of 20 minutes during the summer was determined to be adequate. A winter detention time of 45 minutes is recommended based on typical cold-weather parameters and comparisons of data from other WTPs. Historical detention times during peak-flow conditions are 30 and 55 minutes in the summer and winter, respectively.

During the Near Term Improvements (NTI) Project completed in 2007, a plate settler was added in basin G to test the performance of this treatment device. The past 8 years have shown extremely positive results, providing a 50-percent increase in treatment capacity in basin G. The current plate settler capacity is based on a plate settler loading rate of 0.2 gallons per minute (gpm) per square foot (sf) (gpm/sf) of projected plate area in winter and 0.3 gpm/sf in summer. Sedimentation basins A, B, and C have a different length to width ratio than basins D through G and produce lower quality settled water compared with basin G. See Figure 5-5 for the layout of the existing flocculation/sedimentation basins.

Figure 5-5. Existing Flocculation/Sedimentation Basins with Capacities in Million Gallons per Day

Several alternatives were considered to achieve the desired flocculation times and sedimentation loading rates at 88 MGD for the 2019 Expansion to 85 MGD Project. The alternatives included installing plate settlers in basins D through F. Decommissioning one or more of the old basins was considered, which would require retrofitting additional flocculation stages and installing additional plate settlers. This would allow for flexibility in the site layout and reduce future investment in the flocculation/sedimentation basins. The JWC decided to postpone decommissioning and demolishing all old basins until the 2026 Seismic Resiliency Project to reduce costs and simplify the required modifications. The selected alternative is shown in Figure 5-6. Modifying the seismic resiliency and ultimate buildoutinterim expansion likely will involve constructing a new flocculation/sedimentation basin designed to meet demands through ultimate buildoutinterim expansion, with additional basins required for the future expansion.


WT1010161153PDX 5-7

Figure 5-6. Selected Flocculation/Sedimentation Alternative

5.1.6 Settled Water Conveyance The existing settled water conveyance system is a series of concrete open channels, enclosed conduits, and pipes that convey settled water from the sedimentation basins to the filters as shown in purple in Figure 5-7. The existing conveyance system was previously evaluated and identified as seismically deficient as part of the JWC WTP seismic evaluation (Carollo Engineers, 2008) and was identified as a high value seismic improvement project. The hydraulic capacity was also evaluated, and the current capacity of the structure was found to be approximately 80 MGD; this is less than the 88 MGD necessary to achieve the required capacity for the expansion to 85 MGD.

Existing settling plates

Existing flocculation

New settling plates

Old basins A through C


5-8 WT1010161153PDX

Figure 5-7. Existing Settled Water Flume

The main goal of the settled water conveyance system evaluation was to consider options to provide seismically resilient settled water conveyance to the new filter structure while addressing seismic resiliency issues with the existing settled water flume. Completely replacing the settled water flume was compared with installing a parallel pipe, and combinations of connections between flocculation/sedimentation basins and existing/new filters were considered as well. The JWC decided that connection to seismically deficient structures was not a priority, so the new settled water pipe would connect basins D through G to the new filter facility. Figure 5-8 shows the location and connection points of the selected alternative.

Figure 5-8. Selected Settled Water Conveyance Alternative

Installing an isolation mechanism will be required between basins C and D for flow isolation. The proposed size (72”) of the new settled water pipe will provide capacity for approximately 45 MGD. A parallel pipeline will need to be constructed during the 2026 Seismic Resiliency Project to increase conveyance capacity and could be sized to accommodate ultimate buildoutinterim and future expansion capacity at that time. The new settled water pipeline will be connected to the existing filters to allow for operational flexibility.


WT1010161153PDX 5-9

5.1.7 Filtration The existing filtration system consists of 14 462-square-foot dual-bay filters with air scour-wash capability. A filter influent channel feeds settled water to each filter. Filters 1 through 8 have individual effluent pipes that carry filter effluent to the clearwell underneath the filters, and filters 9 through 14 have combined effluent pipes that carry filter effluent to the clearwell underneath filters 1 through 8. The existing filtration facility is shown in Figure 5-9.

The filters are dual media filters with 12 inches of sand topped with 46 inches of anthracite and have an approved peak loading rate of 8.7 gpm/sf. The existing filters were also previously evaluated and identified as seismically deficient as part of the JWC WTP seismic evaluation (Carollo Engineers, 2008). Constructability analysis completed as part of the 2015 CIP update (Carollo Engineers, 2015) concluded that mitigating the existing building was not feasible, and replacement would be required.

Figure 5-9. Isometric of Existing Filter Structure

Existing filters

Clearwell

FWPS # 2

FWPS # 1


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The WTP experienced the highest water demands to date during summer 2015, which provided new data regarding the peak operating capacity of the filters. The peak sustained output from the filters was approximately 68 MGD. This was accomplished with continuous backwashing of each filter as quickly as possible given the backwash surge and recycle system limitations. This data shows that the filters are not achieving the expected filter run lengths and need to be backwashed more frequently than can be accomplished. As such, the filtration capacity is backwash limited. As an interim solution, JWC purchased and installed a temporary pump to take water from the surge basins directly to the sludge ponds. This will increase the frequency that filters can be backwashed.

Data from the summer 2015 plant operations show that the capacity of the existing filters at the approved loading rate of 8.7 gpm/sf would be 72 MGD based on observed filter run lengths if the surge and backwash recycle system limitation was corrected. This capacity is based on the water quality and WTP operations at this time and may vary under different conditions. The previously assumed capacity of 75 MGD was based on an assumption of longer filter runs; however, during the July 2015 event, the WTP was not able to achieve the longer runs. Therefore, additional filtration capacity is required to provide both a reliable peak capacity of 75 MGD for all partners and expansion to a peak capacity of 85 MGD.

Several alternatives were considered to meet 85-MGD filtration capacity for the WTP expansion. The goals for the new filters were to operate seamlessly with the existing filters, have sufficient capacity, and be a building block for the future construction of additional filters. Since the existing filter structure was categorized as seismically deficient, a new filter facility was proposed to avoid stranded cost. A 924-square-foot deep-bed filter configuration was selected to improve on the existing filters while maintaining similar sizing criteria and backwash characteristics. The new 924-square-foot filters will be twice the size of the existing filters and will backwash one filter bay at a time to use the existing backwash pumps and air scour blowers in finished water pump station (FWPS) 2. The new filters will provide the foundation for the new seismically resilient filter facility that will be expanded as part of the Seismic Resiliency Upgrades and ultimate buildout, interim expansion, and future expansion. The selected alternative for filtration is shown in Figure 5-10 and Figure 5-11.

Figure 5-10. Filtration System Process Flow

Figure 5-11. Isometric of New Filter Design (Lower Level)

Filters

SW FW

BWW

FW Filtered water

(to clearwell)

Backwash Waste

(To Surge Basin)

SWSettled water

Settled water

Settled water

Settled water

Effluent piping

Filter influent channel

Gullet

Filter gallery


WT1010161153PDX 5-11

5.1.8 Clearwell and Disinfection Contact Time The baffled clearwell is fed by the filter effluent and discharges to FWPSs 1 and 2, as shown in Figure 5-12. The clearwell provides a portion of the required chlorine disinfection (CT) and has a maximum capacity of 1.5 MG. The existing clearwell was previously evaluated and identified as seismically deficient as part of the JWC WTP Seismic Evaluation Project, with a recommendation to compact grout (Carollo Engineers, 2008). Constructability analysis completed as part of the 2015 CIP update (Carollo Engineers, 2015) concluded that mitigation of the existing structurebuilding was not feasible and replacement would be required.

Figure 5-12. Isometric of Existing Clearwell

State and federal regulations stipulate minimum CT values that must be achieved depending on the water pH, temperature, and chlorine residual. JWC is required to provide a total of three-log removal and inactivation of giardia and 4-log removal and inactivation of viruses. The conventional filtration process is given credit for 2.5-log removal of giardia and 2-log removal of viruses. The remaining 0.5-log giardia and 2.0-log virus inactivation is accomplished with chlorine in the clearwell and downstream piping.

The finished water CT was evaluated using theoretical baffling factors at conservative temperature and pH values to determine if the requirements were met for existing and future flows. Previous studies have shown that the system provides sufficient disinfection through a combination of clearwell CT and pipeline CT between the clearwell and the first customer. Results show that the clearwell and associated pipeline have the capacity to meet CT goals.

In order to demonstrate to the Oregon Health Authority that the system provides the required CT, a tracer study may be necessary as part of the expansion to 85 MGD to confirm these results. The assumptions for the evaluation are included in Appendix A. The seismically deficient clearwell is scheduled to be replaced or paralleled as part of the 2026 Seismic Resiliency Project, with additional clearwell capacity proposed as part of ultimate plant buildoutthe interim expansion.

Outlet to FWPS #1

Clearwell inlet from filter clearwell

Outlet to FWPS #2


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5.1.9 Finished Water Pumping Two FWPSs pump water from the clearwell to the JWC transmission and storage systems. FWPS 1 was built in 1976 and has a peak capacity of 46 MGD (based on nameplate capacities), while FWPS 2 was built in 1998 and has a peak capacity of 39 MGD (also based on nameplate capacities). The two FWPSs were previously evaluated and both were identified as seismically deficient as part of the JWC WTP seismic evaluation (Carollo Engineers, 2008). As part of that analysis finalized in the 2015 CIP update (Carollo Engineers, 2015), JWC determined that seismic improvements should be made to FWPS 2, and FWPS 1 should be replaced.

Field tests conducted in June 2016 verified the pumping capacity of each pump station to compare with the nameplate data and found that the total pumping capacity of both stations was 87.5 MGD based on several correction factors related to the accuracy of the flow meters; this is sufficient to meet the target peak capacity of 85 MGD for the FWPS. Pumping capacity will need to be confirmed with additional testing once the new flow meters are installed fall 2016.

With the assumption that the total PS capacity is greater than the required 85 MGD, replacement of three finished water pumps in-kind at FWPS 1 was included in the expansion to 85 MGD as part of the JWC WTP CIMP. This approach will not increase the rated capacity of the pump station.

Due to seismic vulnerability, FWPS 1 is planned to be replaced with a new FWPS 3 as part of the 2026 Seismic Resiliency Project. The new pump station is expected to include sufficient spare but empty pump bays for ultimate buildout in the futurethe interim and future expansion projects.

5.1.10 Chemical Systems Most chemical systems are located in the lower level of the operations building with the exception of the sodium hydroxide (caustic) system and powdered activated carbon (PAC). Chemical systems at the WTP include chlorine gas, aluminum sulfate (alum), filter aid polymer, coagulant aid polymer, PAC, and caustic. The existing operations building was previously evaluated and identified as seismically deficient as part of the JWC WTP seismic evaluation (Carollo Engineers, 2008). Constructability analysis completed as part of the 2015 CIP update (Carollo Engineers, 2015) concluded that mitigating the existing building was not feasible, and replacement would be required.

Several modifications are expected as part of the expansion to 85 MGD. Redundancy, pump capacity, storage capacity, and associated injection piping will be evaluated as part of detailed design to determine the necessary modifications. Some metering pump replacement will likely be required. Full replacement of the chemical building is planned as part of the 2026 Seismic Resiliency Project.

The existing chlorine disinfection system utilizes chlorine gas. The Chlorine Disinfection and Chlorine Residual Maintenance Study (Brown and Caldwell, 2013) recommended converting the system over to bulk sodium hypochlorite. As part of the Facility Plan process, the JWC agreed that onsite sodium hypochlorite generation is the preferred solution, based on operator safety and reliability. The current Facility Plan includes this conversion as part of the Seismic Resiliency Upgrades.

5.2 Solids Handling Process The solids handling system at the JWC WTP consists of washwater surge basins, recycle pumping, washwater clarification, sedimentation basin solids pumping, sludge ponds, and solids drying beds. The existing solids handling system is shown in Figure 5-13 and Figure 5-14.


WT1010161153PDX 5-13

Figure 5-13. Existing Solids Handling Process Flow

Figure 5-14. Existing Solids Handling System Layout

5.2.1 Waste Washwater Surge, Recycle, and Clarification Waste washwater from the filter backwash and filter-to-waste flows to the surge basins for equalization prior to being pumped to the gravity thickeners for clarification. The settled solids from the gravity thickener are then pumped to the sludge ponds and the supernatant is gravity recycled to the rapid mix


5-14 WT1010161153PDX

structure. Several limitations are attributed to the existing waste washwater recycle system, including the recycle pump station pipeline limitations and gravity thickeners loading rate. These factors limit the capacity below the recommended design criteria of 2,750 gpm. The existing gravity thickeners and surge basins were previously evaluated and identified as seismically deficient as part of the JWC WTP seismic evaluation (Carollo Engineers, 2008).

The surge system capacity was evaluated based on the number of consecutive backwashes that need to be equalized by the surge system. Typical WTP design practice is to size surge basins to store two filter backwashes and to size the recycle system to pump the maximum daily washwater produced by the filters. A summary of the capacities and design criteria is listed in Table 5-1.

Expanding the existing surge and backwash clarification facilities and collocating the new facilities near the existing assets were carefully considered, because the facilities were identified for future replacement. After evaluation, constructing the new facilities on the south side of the plant near the new filter facility was decided. This will allow for shorter pipe runs and a coherent basis for future expansion of the surge and recycle system as part of the 2026 Seismic Resiliency Project.

Table 5-1. Backwash Surge, Recycle, and Clarification Design Criteria

Parameter Existing 85 MGD

Backwash Surge

Backwash volume from consecutive backwashes 280,000a 420,000b

Total surge volume, gallons 235,000 515,000

Backwash Recycle Pump Station

Maximum total daily backwash volume, gallons 1,820,000c 3,920,000

Pumping capacity, gpm 1,300 2,750

Number of pumps 2+1 2 + 1

Capacity per pump, gpm 750 1,375

Gravity Thickeners (Backwash Clarification)

Maximum hydraulic loading rate, gpm/sf 0.4 0.4

Maximum solids loading rate, lbs/sf-day 4.0 4.0

Maximum flow rate, gpm 1,300 2,750

Maximum design solids loading, lbs/day 13,000 27,750

Note: All existing capacity values are taken form the 2012 plant expansion preliminary design (Carollo Engineers, 2012).

a Volume calculated as two small filter backwashes (140,000 gallons each).

b Volume calculated as one large filter backwash (280,000 gallons) followed by one small filter backwash (140,000 gallons).

c The volume represents a maximum of 13 backwashes per day based on data from July 2015.

Notes:

gpm gallons per minute gpm/sf gallons per minute per square foot lbs/day pounds per day lbs/sf-day pounds per square foot per day MGD million gallons per day

Evaluating the existing system also looked at what improvements could be made to the existing backwash clarification process. Constructing a new clarification facility was compared with sending the waste washwater to the solids drying beds where it would be removed by sedimentation. Sending


WT1010161153PDX 5-15

backwash waste to the solids drying beds was chosen due to its relative low cost and low hydraulic loading rate. However, based on input from JWC staff, using the solids drying beds was determined to not be feasible without adding an additional solids drying bed to allow for separating sedimentation basin flow and waste washwater flow.

The layout of backwash recycle system is shown in Figure 5-15. The alternative includes a new 280,000-gallon surge basin, recycle pump station, solids drying bed, and piping from the new pump station to each solids drying bed. The existing recycle pump station will act as an overflow for the new surge basin, which will require modifying the conveyance system. The 2026 Seismic Resiliency Project is expected to include replacing the existing surge basins. No additional capacity is anticipated for ultimate buildoutthe interim or future expansions.

Figure 5-15. Expansion to 85 Million Gallons per Day Backwash Recycle Layout

5.2.2 Sedimentation Basin Solids Conveyance Settled solids from the sedimentation basins are collected and conveyed to the solids diversion pump station where they are pumped to the solids drying beds. The operators can send the sedimentation basin solids to the sludge ponds, and solids will be conveyed to the surge basins when the solids diversion pump station overflows. Each flow path is shown in Figure 5-16. The pump station and associated piping were analyzed to determine the impact of increased flows on the system.


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Figure 5-16. Existing Sedimentation Basin Solids Conveyance System

The theoretical maximum sludge blowdown from the sedimentation is within the acceptable range for the existing 6-inch pipe. However, the 6-inch line is not adequate for multiple concurrent blowdowns. Therefore, the existing 6-inch line from basins D through G will be upsized with a 12-inch line to the solids diversion pump station. This line will run parallel to the 6-inch drain from basins A through C.

Basins D through G also use this same existing 6-inch pipe for draining basins when they are taken off line. This small pipeline results in unnecessarily long basin drainage times, which increases the time the basins must be offline and causes a delay in sludge blowdown for other basins. To mitigate this issue, a new 6- to 10-inch pipe will be added into basins D through G to allow for suction of water out of the basins for draining. This water can be pumped to the sludge ponds.

5.2.3 Solids Dewatering Settled sludge from the sedimentation basins and gravity thickeners is currently conveyed to the solids drying beds and sludge ponds as shown in Figure 5-17, with all solids from the gravity thickeners going to the sludge ponds and most sedimentation basin solids going to the solids drying beds.

The solids drying beds comprise an engineered system that allows solids to settle and pumps the decanted and underdrain supernatant waters back to the rapid mix structure. The sludge ponds comprise a passive system that allows solids to dewater via infiltration and evaporation with no decanting/recycle capability. Evaluation of the system focused on the solids drying beds that are operationally limited due to capacity, inflexibility in scheduling, and uneven distribution of solids throughout the length of the drying beds. An analysis of solids drying beds historical data showed that a reasonable target for the dried solids was 40 percent solids by weight at the time of removal. To achieve this goal, a fill depth and operations schedule were recommended, as well as modifications to the solids inlet piping in the beds to more evenly spread the discharge water. A summary of the design criteria is presented in Table 5-2.


WT1010161153PDX 5-17

Figure 5-17. Existing Solids Dewatering System

The addition of one solids drying bed (solids drying bed 5) will allow the JWC WTP to achieve the solids dewatering design goals for the 2019 Expansion to 85 MGD Project. The land availability and relative low cost of a solids drying bed make them an effective technology for the JWC WTP. Piping and connections to the decant pump station and underdrain pump station will accompany the construction of the new solids drying bed. Note that a fifth solids drying bed and piping to allow waste washwater to be kept separate from sedimentation basin solids are included in the 2019 Expansion to 85 MGD Project as described in Section 5.2.1. This addresses concerns with the mixing of backwash solids and settled solids by providing flexibility in the solids handling operations. The additional flow from the waste washwater solids will require upgrading the existing decant pump station, and constructing a new decant pump station may be necessary for the two new solids drying beds.

Using an auger machine to turn over solids during the drying cycle was also considered to encourage higher drying efficiency. JWC will continue to monitor the need of this machine into the future. No additional investment is expected for the 2026 Seismic Resiliency Project for solids handling, while an additional solids drying bed (solids drying bed 6) is expected to be constructed as part of the ultimate interim expansionbuildout,. and three additional solids drying beds are expected to be constructed as part of the future expansion.

LEGENDExisting backwash waste

Existing settled solids

Existing decant recycle

Solids drying beds

Sludge ponds

Solids diversion pump station

Gravity thickeners

Decant pump station

Underdrain pump station

Surge basins

Solids diversion pump station overflow


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Table 5-2. Solids Dewatering Design Criteria

Parameter Existing 85 MGD

Sedimentation Basin Solids

Solids production, lbs/year 2,500,000 3,100,000

Maximum solids loading rate, lbs/sf 17 17

Assumed solids concentration during fill, percent solids 7.5 7.5

Solids Density During Fill, lbs/cf 65 65

Maximum recommended fill depth during filling, feet 3.5 3.5

Average fill time per basin, months 5 4

Drain time basin, months 1 1

Drying time per basin, months 9 11

Dried solids target, percent solids 40 40

Notes:

lbs/cf pounds per cubic foot lbs/sf pounds per square foot lbs/year pounds per year MGD million gallons per day

5.2.4 Solids Disposal Dried solids in the sludge ponds and solids drying beds are currently excavated, transported, and disposed of at the Hillsboro Landfill at a total cost of about $60 per ton of excavated solids. Reduced costs could be achieved by providing additional onsite drying resulting in reduced disposed weight or by reducing hauling and disposal costs by creating a disposal system on JWC-owned land.

When scheduling and performance are better, the solids drying beds produce material with solids concentrations upwards of 40-percent solids. These solids can be excavated and hauled directly to the landfill. However, limitations in the existing solids drying beds have caused the JWC WTP to use a two-step drying process to achieve higher solids concentrations. Solids are typically removed from the solids drying beds and placed in the sludge ponds for additional drying prior to trucking to the landfill.

The team also considered the feasibility of a JWC-owned monofill as a solids disposal option. The permitting and land acquisition requirements are under preliminary investigation to provide insight into the feasibility of this option long term. The initial estimate of land required for a 50-year landfill is 10 to 20 acres. Depending on the cost of land acquisition and construction requirements for the landfill, this alternative may provide a savings on the order of 25 percent compared to current disposal costs when considered on an annual basis; however, much of the cost will be associated with the initial land purchase and construction.

5.3 Non-process Facilities

5.3.1 Operations, Maintenance, and Chemical Buildings The operations, maintenance, and chemical building is a combined structure in the center of the WTP, which was originally built in 1974 and was used for mechanical solids dewatering. The concrete tilt-up structure was previously identified as seismically vulnerable and has been scheduled for replacement as part of the 2026 Seismic Resiliency Project. Additionally, the WTP staff has suggested separating


WT1010161153PDX 5-19

operations and chemicals for safety reasons, because most of the chemical systems, including chlorine gas, is currently housed in the operations building.

For the new operations building to be constructed in the future, planning level costs were developed using the current space used for these facilities, discussions with WTP staff about space requirements, and comparison of several similar sized WTP operations and maintenance buildings. The concept and cost estimate for the new operations and maintenance buildings were developed using conservative assumptions. The design for this facility should will include a more in-depth look at the requirements for this facility to arrive at the ultimate configurationinterim and future expansion configurations.

5.3.2 Electrical Systems The electrical system at the WTP is adequate to supply power to the plant and raw water pump station is adequate for the proposed Expansion to 85 MGD. Opportunity also exists to increase the capacity of the switchgears and add transformers by installing additional cables between the equipment onsite. However, this additional capacity will not be required in the 2019 expansion. Additional capacity may be needed within the WTP for the seismic resiliency upgrades due to the need to keep the existing plant in operation while starting up the new facilities. The new facilities have been located outside the existing runs of major electrical duct banks to facilitate the future construction. Further description of the electrical system and capacity is provided below and shown in Figure 5-18.

Figure 5-18. Existing Water Treatment Plant Electrical System

As part of the recently completed Standby Power Project, the two Portland General Electric (PGE) services for the WTP and SHPP were combined into one Medium Voltage (MV) service. The new Standby Power building houses both the standby generators and the New Main MV Switchgear (NMMVS).

The “old” WTP Main MV Switchgear (OMMVS) is back-fed from the NMMVS, using one set of 750 thousand circular mil (kcmil), 15 kilovolts (kV), 105°C, copper cables. The OMMVS is rated for 1,200 amps; however, the 750 kcmil feeders are only rated for 610 amps. At 12.47 kV, 3-phase, this would allow up to 13,175 kilovolt-ampere (kVA) of load. Currently, there are (6) transformers connected to the


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OMMVS; the sum total of the transformer ratings is 12,000 kVA. Assuming all six transformers are fully loaded, this would leave 1,175 kVA of capacity. However, most of the connected transformers are running at less than full capacity, even during peak demand periods. Based on data provided by PGE, the peak demand of the OMMVS over the last two years is 5,387 kVA. The NEC allows use of this peak value, multiplied by 125 percent, to determine available capacity on an existing service. Given that approach, the current available capacity of the OMMVS is approximately 6,400 kVA.

It would be possible to increase the capacity at the OMMVS by running a second set of MV cables from the NMMVS. Running a second set of 750 kcmil MV cable would provide an increase of approximately 340 amps, or a total of 950 amps. Due to additional heating effects, the ampacity would not be doubled. An increase in feeder size by 100 amps would provide an approximate 2,000 kVA of additional capacity.

Four of the transformers on the OMMVS are connected through a field-located, MV Switchgear (Vista), which is rated for 600 amps. The Vista has a total of five load switches, only four of which are currently used; thus, there is room to add one additional transformer to the Vista. The feeder to the Vista is one set of 350 kcmil, 15 kV, 105°C copper cable, which has an ampacity rating of 415 amps. This provides 8,963 kVA of total capacity. The combined ratings of the four existing transformers is 6,000 kVA, which leaves approximately 2,963 kVA of available capacity on the Vista, assuming the existing transformers are fully loaded; they are not. Based on data gathered on site at the WTP, the existing, combined peak demand of the four transformers is approximately 2,600 kVA. Taking 125 percent of this value would leave approximately 5,700 kVA of available capacity on the Vista. However, it should be noted that the Vista is also limited by the available capacity of the OMMVS that feeds it. The full 600-amp rating of the Vista can be realized by running a second set of MV cable from the OMMVS. Running a second set of 350 kcmil MV cable would provide the full, 600-amp capacity.

As part of the 85-MGD upgrade project, a new filter building is to be constructed, along with a new electrical room for the new pumps and other electrically driven mechanical systems. The current plan is to install a fifth transformer from the Vista to provide the required power. This would take up the last available load switch in the Vista. It is also permissible and possible to “daisy-chain” transformers. That is, more than one transformer can be fed from a single load switch. This was how the four existing transformers connected to the Vista were originally connected. The downside of this configuration is that the daisy-chained transformers cannot be isolated. However, should additional transformers be required in the future, and there are no available load switches, daisy-chaining the new transformers would provide the required power without the expense of additional MV switchgear.

Due to the life expectancy of major electrical equipment being less than the time horizons for implementation of the interim and future expansions, the required improvements to the plant electrical system were not included in this evaluation.

5.3.3 Sustainability As the JWC makes improvements and expands the WTP, alternatives and opportunities will be viewed through the lens of sustainability. The current Facility Plan includes the following sustainable features:

• Reduction in water loss—The upgraded WTP will significantly decrease the amount of water lost through the treatment process. At present, water from the gravity thickeners is released to the sludge ponds. Additionally, sedimentation basin blowdown is often diverted to the ponds during the summer to accelerate drying of the solids drying beds. The additional drying bed capacity and removal of the gravity thickeners will result in more of the water being recycled through the treatment process. Although the plant will be designed for 3 percent water loss to account for occasional process upsets, the normal treatment process will be much more efficient with water lost primarily to evaporation or infiltration in the ponds.


WT1010161153PDX 5-21

• Premium efficiency motors—Replacement motors for large pumps at the WTP will be premium efficiency. The current project includes five 400-hp pumps, two 800-hp pumps, and two 100-hp pumps.

• Installation of settling plates—Settling plates will be installed in sedimentation basins D, E, and F to increase their respective treatment capacities from 10 MGD to 15 MGD, each. This eliminates the need to build two new sedimentation basins.

• Preservation of existing wetlands

• Efficient lighting—The new facilities will include LED lights for minimum energy use.

5.4 Future Treatment Processes Future water quality and regulations cannot be accurately predicted, although considering what future water quality or regulations might occur is prudent. Four categories of contaminants were considered in this discussion: disinfection byproducts, pathogens, algal toxins, and pesticides and emerging contaminants. These contaminants are described briefly below:

• Disinfection byproducts (DBPs)— The most commonly regulated DBPs related to the JWC WTP are total trihalomethanes and haloacetic acids. Future regulations could look to reduce the maximum contaminant levels for these compounds or regulate new ones. These byproducts form as a result of reactions between organic compounds in the water and chlorine used for disinfection. The most effective approach to reducing the formation of these byproducts is to remove more organics, referred to as precursors, from the water prior to disinfection.

• Pathogens—The currently regulated pathogens include bacteria (measured as coliforms), viruses, Giardia cysts, and Cryptosporidium cysts. Different treatment processes have different effectiveness for removal or inactivation of these organisms. It is possible that new indicator organisms will be identified in the future.

• Algae and algal toxins—Algae come in many forms and can impact treatment plants in multiple ways including clogging of filters and creating taste and odors. Additionally, blue-green algae (cyanobacteria) are capable of releasing harmful toxins. These toxins can harm the nervous system, liver and kidneys. During an outbreak in 2014 in Toledo, Ohio, a do not drink/do not use water notice was ordered. The State of Oregon has since established provisional health based guidelines for several cyanotoxins including those in Table 5-3.

Table 5-3. Provisional Health-Based Water Guideline Values for Four Cyanotoxins (ppb or µg/L), Oregon Health Authority, June 17, 2015

Water Use Anatoxin-a Cylindrospermopsin Microcystins Saxitoxins

Drinking water Adults (age 6 and older) 3 3 1.6 1.6

Drinking water Children (age 5 and younger) 0.7 0.7 0.3 0.3

Nondrinking uses (recreation) 20 20 10 10

Notes:

µg/L micrograms per liter ppb parts per billion

The JWC WTP has experienced taste and odor events in the past related to algae upstream. Toxic algae blooms have occurred elsewhere in the State and are therefore considered in this discussion.

• Pesticides and Contaminants of Emerging Concern (CECs) – CECs include a broad range of potential environmental contaminants, generally resulting from human activity. They include pharmaceuticals,


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industrial wastes and byproducts, and pesticides/herbicides. As the Tualatin River upstream of the WTP is largely agricultural at this time, pesticides are the greatest present threat in this category. However, as the area is urbanized, other contaminants may become of greater concern.

To address potential changes, the Facility Plan provides flexibility to achieve a range of treatment options to serve JWC well into the future. The following advanced treatment technologies were discussed during the planning process, along with their relation to JWC WTP and potential changes to water quality and regulations:

• Ultraviolet (UV) disinfection—Uses enclosed pipe segments (reactors) to penetrate the water with UV light and inactivate pathogens. This option has the smallest footprint.

• UV and oxidation—Applies a much higher dose of UV light in addition to a chemical oxidant (typically hydrogen peroxide) to break down compounds into smaller elements. This option takes up about twice as much space as UV by itself and uses greater than 40 times more energy.

• Ozone—Oxidation and disinfection process, which breaks down organic and inorganic compounds including algal toxins and taste and odor compounds. Ozone also inactivates pathogens including giardia, cryptosporidium, bacteria, and viruses. Hydrogen peroxide can also be added with the ozone for advanced oxidation. This option has the largest footprint and requires construction of an ozone contact basin.

• Ozone and biological-activated carbon (BAC)— Granular-activated carbon (GAC) commonly replaces anthracite in the dual-media filter and allows for bacteria to grow on it, making it biologically active. Oxidation occurs via ozone to break down organic matter, which is then readily available for assimilation by the bacteria. BAC works well with ozone for additional organics removal. If the GAC is replaced on a regular basis, then additional organics removal through adsorption is possible. This option has the same footprint as the ozone only option, assuming existing filters are used as BAC filters.

Alternative performance for various contaminants is compared in Table 5-4.

Table 5-4. Performance of Advanced Treatment Processes Against Common Contaminants

Disinfection Byproducts Pathogens Algal Toxins

Pesticides and Emerging

Contaminants

UV

UV and Oxidation

Ozone

Ozone and BAC

Legend: Excellent Good Fair Poor Notes: BAC biological-activated carbon UV ultraviolet

If ozone were installed at the JWC WTP, then it would be installed between sedimentation and filtration. If UV (without oxidation) were to be installed, then it would be installed downstream of filtration and upstream of the clearwells. The JWC decided to reserve space for future treatment processes both upstream and downstream of the new filtration facility to account for these potential needs. Additionally, each treatment system would introduce additional headloss in the WTP. To prevent the need for an intermediate pump station, additional head can be provided in the WTP hydraulic profile. In the case of JWC, the substantial available head between sedimentation and the clearwells allows for


WT1010161153PDX 5-23

excess head for these two treatment processes to be retained on either side of filtration. This approach allows for flexibility if advanced treatment is required in the future. Locations reserved for these treatment components are shown on the ultimate interim expansionbuildout site plan included in Section 8.

SECTION 6

WT1010161153PDX 6-1

6Expansion to 85 MGD and Related Improvements

6.1 Project Definition The 2019 Expansion to 85 MGD Project includes four major objectives:

• Remove hydraulic bottlenecks in the existing WTP to provide a reliable 75-MGD peak capacity for all JWC partners.



• Complete previously identified CIMPs.

Improvements to reach 75 MGD are necessary for all partners and will be funded based on the current prorated ownership of the WTP. However, the 10-MGD expansion from 75 to 85 MGD is being undertaken and funded by the City of Hillsboro and TVWD and will increase their respective WTP ownership shares. This project is scheduled to be completed by June 2019 to meet the water demands projected by these two partners.

6.1.1 Project Components Table 6-1 summarizes the improvements expected as part of the 2019 Expansion to 85 MGD Project. A comparison to the 2015 CIP is also provided. The most significant changes from the 2015 CIP include:

• Reconfiguration of the solids handling system to minimize stranded assets

• Installation of larger filters in response to the capacity limitations revealed during July 2015 peak demands

• Reduction in the scope of seismic improvements

The changes are described in more detail in the following Facility Plan.

Table 6-1. Components for 2019 Expansion to 85 Million Gallons per Day Project and Related Improvements

Facility Proposed Improvements 75 MGD 85 MGD CIMP Seismic


SHPP, raw water pump station

Increase capacity of pumps to 400 horsepower each

✓

✓

Add vortex suppression systems ✓

Make seismic improvements: nonstructural—restrain cabinets

✓ ✓

Make seismic improvements: structural

✓

Install rotating raw water trash screens

✓

SECTION 6 – EXPANSION TO 85 MGD AND RELATED IMPROVEMENTS

6-2 WT1010161153PDX




Rapid mix facility

Remove fiberglass baffle wall ✓ ✓

Relocate jet injectors ✓

Remove weir to basins D through G

✓

Add flow meters and flow control valves for basins D through G and replace basins A/B flow meter

✓

✓

Upgrade flash mix pumps ✓

✓

Make seismic improvements: nonstructural—restrain grating

✓ ✓

Flocculation/ sedimentation basin

Install plate settlers in basins D through F

✓

✓

Improve sedimentation basin drains

✓

✓

Rehabilitate chain and flights in basins D through G

✓ ✓

Make seismic improvements: nonstructural—restrain basin G plate settlers

✓ ✓

Make seismic upgrades: structural ✓

Repair floor cracks in basins A through C

✓

Add hatches to basins A through C ✓

Settled water conveyance

Settled water pipeline connected from Basin D to existing and new filters (Included in filter yard piping cost)

✓ ✓

Add polymer mixing in new settled water pipe (Included in filter costs)

✓

Filters

Install two new filters (924 sf each) ✓ ✓

Install two new filters (426 sf each) ✓

Install new filter yard piping ✓ ✓

Paint filter 1 through 8 gallery piping and extend clearwell vents to atmosphere

✓ ✓

Replace media in filters 1 through 13

✓

✓

Evaluate and repair settling in filter 13

✓

Make seismic improvements: nonstructural—restrain HVAC equipment

✓ ✓


WT1010161153PDX 6-3




FWPS

Replace FW Pump 2 and 6

(replace FW Pump 1 as budget allows)

✓ ✓

Replace BW Pump 1 and 2 ✓ ✓

Make FWPS 1 seismic improvements: nonstructural—restrain HVAC and electrical equipment

✓ ✓

Make FWPS 2 seismic improvements: nonstructural—restrain cabinets

✓ ✓


Construct new surge basin ✓

✓

Make new to old surge basin connection

✓

Upgrade existing recycle pump station

✓

Construct new recycle pump station

✓

Install a new gravity thickener ✓

Replace existing thickener mechanisms

✓

Solids dewatering

Construct new solids drying bed (bed 4)

✓ ✓

Construct second new solids drying beds (bed 5)

✓

Modify solids drying bed flow ✓

Decant pump station capacity increase

✓

Decant pump station flow meters ✓

Abandon gravity thickeners in place

✓

Chemical facilities

Upgrade chemical feed pumps ✓

✓

Replace chlorine feed lines to FWPS 1, FWPS 2, and settled water flume

✓

✓

Install chlorine residual monitoring ✓

Increase chemical containment capacity

✓

Operations building

Add water manager’s office ✓

Make seismic improvements: nonstructural—restrain cabinets and tanks

✓ ✓

Make seismic improvements: structural—reinforce office window

✓ ✓

Make seismic improvements: structural—foundation improvements

✓ ✓


6-4 WT1010161153PDX





Replace and rehabilitate two air compressors and air lines

✓ ✓

Replace septic tank and leach field ✓ ✓

Redirect waste from analyzers at pump stations 1 and 2

✓ ✓

Make seismic improvements: nonstructural—restrain sodium hydroxide tanks

✓ ✓

Make seismic improvements: nonstructural – anchor and brace electrical cabinets, duct muffler and battery charger at MCC/Generator Building

✓ ✓

(Construct sidewalks at basins and more parking as budget allows)

✓ ✓


Upgrade WTP communications network

✓

Studies/ updates

Conduct electrical assessment ✓

✓

Notes:

BWPS backwash pump station CIMP Capital Improvement Maintenance Project CIP capital improvement program FW finished water FWPS finished water pump station HVAC heating, ventilation, and air conditioning

MCC motor control center MGD million gallons per day sf square feet SHPP Spring Hill Pumping Plant WTP water treatment plant

Figure 6-1 shows the planned layout for the JWC WTP following the completion of the 2019 Expansion to 85 MGD Project. This project includes adding new plates in basins D through F, two new filters, a new surge basin, and two new solids drying beds. Figure 6-2 shows the process flow diagram for the JWC WTP following the completion of the 2019 Expansion to 85 MGD Project.

6.1.2 Hydraulics The proposed project elements will provide for a peak flow of at least 88 MGD through the treatment plant to produce a finished water peak of 85 MGD. Improvements include reducing the headloss through the rapid mix facility and providing an additional flow path for settled water to reduce the headloss between the sedimentation basins and the filters. Figure 6-3 shows the JWC WTP hydraulic profile following completion of the 2019 Expansion to 85 MGD Project.

6.1.3 Capacity The 2019 Expansion to 85 MGD Project has a stated goal of establishing a WTP 85-MGD peak capacity. To achieve this goal, the WTP will need to be able to deliver 85 MGD of finished water to the transmission system. For this to occur, the remaining processes will need to be able to produce approximately 88 MGD (rapid mix to filters). The required raw water diversion rate will be more than 85 MGD, but less than 88 MGD most of the time because most water lost to solids handling is recycled to the WTP head. Refer to Section 5.1.1 for a more detailed explanation of this topic.


WT1010161153PDX 6-5

Figure 6-1. Water Treatment Plant Layout after 2019 Expansion to 85 Million Gallons per Day Project and Related Improvements

Each WTP component has an inherent capacity based on the historical performance or selected design criteria for that process. Table 6-2 shows the maximum peak, firm, winter sustained, and seismic capacity that can be expected from each facility following the completion of the 2019 Expansion to 85 MGD Project. Based on this, the summertime limiting factor for peak WTP flow is expected to be filtration or raw water pumping. The maximum winter sustained capacity following the same project is 53 MGD, based on expected performance of the flocculation system.

6.1.4 Winter Sustained Capacity Analysis to confirm the existing or future winter-sustained capacity was not completed as part of this facility planning process. The winter-sustained capacity highly depends on actual water quality. The values presented for winter-sustained capacity in the 2012 Plant Expansion Preliminary Design (Carollo Engineers, 2012) generally represent the types of capacities that can be expected, with three additional items to consider:


6-6 WT1010161153PDX

• Winter flocculation/sedimentation basin capacity highly depends on water temperature and flocculation time. The value presented in the 2012 Plant Expansion Preliminary Design (Carollo Engineers, 2012) of 53 MGD represents 35 minutes of flocculation time. This design criterion is acceptable for moderately cold water above 5°C. However, for extremely cold water temperatures, a flocculation time of up to 45 minutes may be required, which would reduce the flocculation capacity to 41 MGD. Increasing this time would require adding more flocculation stages in the existing basins.

• Adding two new 924-square-foot filters and upgrading the waste washwater-handling system will increase the winter sustained capacity of the filtration system over what it was before the 2019 Expansion to 85 MGD Project. Actual winter capacity improvement will be observed based on actual plant and pilot system performance.

• Previous clearwell analysis appears to have been completed without considering worst-case water temperature and pH. Considering worst-case water temperature and pH could reduce the clearwell winter capacity during the coldest water periods to 64 MGD but may also be increased by increasing the chlorine residual.

In summary, the winter sustained capacity of the JWC WTP as defined in Section 2-5 are not likely to increase; however, for most of the operational period, the WTP will have more than this capacity. During some extreme water quality events, the WTP may be required to reduce production, which might curtail aquifer storage and recovery injection and other similar partner activities.

6.2 Project Schedule The 2019 Expansion to 85 MGD Project began with facility planning in the first half of 2016 and proceeded directly into design. Construction is scheduled to begin in early 2017, and the upgraded WTP is scheduled to be online June 2019.

6.3 Project Budget The 2019 Expansion to 85 MGD Project includes components that are paid for by the JWC partners in different ownership shares. The following section defines how the cost splits were determined.

6.3.1 Project Budget by Project Component The cost of each component is broken out between the 75 MGD and 85 MGD capacity projects as shown in Table 6-3. The estimates provided are generally prepared as Class 4 estimates with an accuracy in the range of +50 percent to -30 percent of the cost shown. The cost estimating approach is described further in Appendix B. While the 75 MGD expansion is not a standalone project, it was important for partner allocations to identify separately any project cost that contributes to establishing a WTP capacity of 75 MGD. Note that the rapid mix, filters, and solids handling all have a portion allocated to the 75 MGD expansion, as the existing capacity of these facilities is below 75 MGD. The total project cost was compiled by combining the costs of the 75-MGD and 85-MGD expansion with the 2019 CIMP and the life-safety seismic improvements (Phase I seismic).


WT1010161153PDX 6-7

Figure 6-2. Process Flow Diagram showing the Water Treatment Plant after the 2019 Expansion to 85 Million Gallons per Day Project

M

M

M

M

FW

BWW

REC

CW

M

M

M

FLOW

CONTROL

VALVE

CW

CW

RIVER

SOURCE

RECYCLED

WATER

(DRYING BEDS)

FWSW

PD

SW

SW

SW

SW

BASIN C

BASIN B

BASIN A

BASIN D

BASIN E

BASIN F

BASIN G

36" RW

42" RW

FINISHED

WATER

(TO DISTR)

WW

REC

WW

REC

WW

RAPID MIX

WW

WW

REC

REC

RECBWW

SS

BWW

BWW

BWW

REC

UD

SOLBWW

BWW

SS

SS

BWW

SS

FW

FW

12

3 4

5

6

LEGEND

1. Modifications to existing rapid mix2. New plate settlers3. New settled water conveyance

4. New filters5. New surge basin and recycle pump station6. New solids drying beds


Rapid mix basinFlocculation/

sedimentation basins

Filters Clearwell FW PS #1 FW PS #2

Solids drying beds

Surge basins

RecyclePS

Decant PS

Solids diversion

PS

Underdrain PS

Solids to offsite


WT1010161153PDX 6-9

Figure 6-3. 2019 Expansion to 85 Million Gallons per Day Project Hydraulic Profile


WT1010161153PDX 6-11

Table 6-2. 2019 Expansion to 85 Million Gallons per Day Project Unit Process Capacity

Facility/Process

Process Capacity (MGD)

Peaka Firmb Post-Seismic Eventc

Raw water delivery (Intake, Spring Hill Pumping Plant, and raw water pipelines)

To be determinedd To be determinedd 0

Rapid mix and flow split 90 90 0

Flocculation/sedimentation basins 90 90 60e

Filtration net capacity 86 76 20g

Settled water conveyance 90 or moreg 90 or moreg 60h

Disinfection and clearwell 85 or morei 85 or morei 0

Finished water pump stations 87j 73j 0j

Backwash waste (surge basins and recycle pumps)

85 or morel 85 or morel 85 or morem

Solids drying beds 85 or moren 85 or more 85 or more

a Peak capacity is defined by JWC as the summer capacity that can be sustained for a minimum of 3 days with all units in service.

b Firm capacity is defined by JWC as the summer capacity that can be sustained with the largest pump or filter in a system out of service.

c Seismic vulnerability of facilities was taken from 2015 CIP update (Carollo Engineers, 2015) and 2008 seismic evaluation (Carollo Engineers, 2008) for the 475-year earthquake and greater. No seismic analysis was performed as part of the facility planning process.

d To be determined based on improvement to existing pumps from upsizing to 400 horsepower. e Value based on loss of sedimentation basins A through C. Includes only sedimentation basins D through G. f Value based on loss of filters 1 through 14. g Value modeled at 90 MGD; additional flow may be achievable. h Value based on new 72-inch settled water pipe connecting sedimentation basin D to new and existing filters. i Value based on theoretical modeling completed as part of this 2016 facility planning project; it assumes pH of 8.0, Cl2 residual of 0.9 mg/L, water temperature of 12.5°C, and clearwell baffling factor (T/T10) of 0.6. It takes credit for 21 minutes of CT in pipeline to WTP operations building (first customer). Higher flows are possible, but actual capacity will vary significantly depending on information not available at this time such as assumed flow split to each pump station and to each of the finished water pipelines.

j Value from 2012 plant expansion preliminary design (Carollo Engineers, 2012). Based on testing performed in June 2011 and evaluation of pump curves.

k Value based on loss of FWPSs 1 and 2 due to liquefaction. l System sized to recycle two backwashes per new 924-square-foot filter per day with surge capacity for two backwashes of new 924-square-foot filters. It assumes one solids drying bed is dedicated to backwash wastewater recovery. Includes one installed standby pump.

m Based on adequate pumping capacity in new surge and recycle facility to recycle a new 924-square-foot filter backwash in 1 hour.

n Assumes four solids drying beds for sedimentation basin solids and one for backwash waste water recovery.

Notes:

CIP capital improvement program Cl2 chlorine CT [chlorine concentration x] contact time JWC Joint Water Commission mg/L milligrams per liter MGD million gallons per day WTP water treatment plant


6-12 WT1010161153PDX

Table 6-3. Estimated 2019 Expansion to 85 Million Gallons per Day Project Budget by Component

Facilities 75 MGD

Expansiona

85 MGD Expansiona

CIMP: 2016-2019a

Phase I Seismica

2016-2019 Totala

2015 CIP Updateb

Raw water pump station

$1,225,000

$1,225,000 $3,470,000

Raw water pipelines

$0 $0

Rapid mix facility $130,000 $640,000

$5,000 $775,000 $985,000

Flocculation/sedimentation

$4,300,000 $850,000 $140,000 $5,290,000 $7,000,000

Filtration $3,900,000c $7,000,000c $1,360,000 $1,000 $12,260,000 $7,700,000

Clearwell

$0 $0

Finished water pump station

$1,050,000 $54,000 $1,100,000 $1,930,000

Backwash surge and recycling $720,000 $2,430,000

$3,150,000 $13,370,000

Solids dewatering $3,300,000 $1,740,000 $50,000

$5,090,000 $810,000

Chemical facilities and systems

$710,000

$710,000 $630,000

Operations building

$50,000 $190,000 $240,000 $1,200,000


$340,000 $30,000 $370,000 $380,000

Finished water transmission lines

$0 $680,000


$200,000

$200,000 $0

Studies and CIP updates

$75,000

$75,000 $1,500,000

JWC project administration $187,000 $390,000 $113,000 $10,000 $700,000 $0

Completed CIMP Projects $0 $900,000

Total $8,240,000 $17,125,000 $4,975,000 $430,000 $31,200,000 $30,000,000



c Cost split for filtration includes 3 MGD and all yard piping in 75 MGD expansion and 10 MGD in Expansion to 85 MGD.

Notes:

CIMP capital improvement maintenance projects CIP capital improvement program JWC Joint Water Commission MGD million gallons per day

6.3.2 Joint Water Commission Partner Cost Allocation A summary of the partner allocations is shown in Table 6-4 and Table 6-5. Note that while the estimated cost for each facility upgrade has changed from the 2015 CIP Update (Carollo Engineers, 2015), each partner’s share in the project is within 3 percent of the project cost.


WT1010161153PDX 6-13

Table 6-4. Project Allocations by Partner

Partner 75 MGD, Seismic Life-Safety, and

CIMP (percent) Expansion to 85 MGD (percent)

Tualatin Valley Water District 16.7 20.0

City of Hillsboro 45.0 80.0

City of Beaverton 23.0 N/A

City of Forest Grove 13.3 N/A

Notes:

CIMP capital improvement maintenance projects MGD million gallons per day

Table 6-5. Project Budget by Partner

Partner Total Project 75 MGD, Seismic,

and CIMP Expansion to 85 MGD

Tualatin Valley Water District $5,790,000 $2,240,000 $3,550,000

City of Hillsboro $20,250,000 $6,060,000 $14,190,000

City of Beaverton $3,370,000 $3,370,000 $0

City of Forest Grove $1,790,000 $1,790,000 $0

Total $31,200,000 $13,460,000 $17,740,000



Notes:

CIMP capital improvement maintenance projects MGD million gallons per day

SECTION 7

WT1010161153PDX 7-1

7Seismic Resiliency Upgrades

7.1 Project Definition The Seismic Resiliency Upgrades are planned to address significant seismic concerns related to the WTP meeting the LOS goals stated in Section 1. The primary goal that factors into the selection and sizing of new facilities to be constructed is the goal to have 42 MGD capacity (average day demand) available immediately following or shortly after each of the seismic events. Rather than implementing a partial WTP replacement, the Facility Plan moves forward the final determination of the 2015 CIP Update to replace all vulnerable facilities in full. This will result in 85 MGD of seismically resilient capacity shortly

after the design seismic events. Ultimately, the Commission will determine in the future what WTP facilities will be built, and the resiliency standards that will be met by those new facilities.

This project is expected to involve replacing most of the WTP facilities and buildings, with only a few newer (post-1998) facilities remaining, including

• Flocculation/sedimentation basins D through G

• FWPS 2

• New generator building (standby power)

• New filters and surge basin constructed for the expansion to 85 MGD

• The solids drying beds will remain in operation with no modifications

The new facilities will be built around the existing and operating WTP and require careful scheduling to maintain effective operations throughout the improvements, and include:

• New or upgraded raw water pump station

• Replace raw water transmission mains

• Replace rapid mix facility

• Replace flocculation/sedimentation basins A-C

• Replace filters 1 through 14

• Replace clearwell

• Replace FWPS 1

• Replace the operations and chemical building

• Upgrade disinfection from chlorine gas to onsite hypochlorite

The project is described in the following sections.

7.1.1 Project Components Table 7-1 summarizes the improvements expected as part of the Seismic Resiliency Upgrades. Refer to the 2008 Seismic Hazard Mitigation Study (Carollo Engineers, 2008) for details on seismic improvements to existing facilities.

SECTION 7 – SEISMIC RESILIENCY UPGRADES

7-2 WT1010161153PDX

Table 7-1. Project Components for Seismic Resiliency Upgrades

Facility Proposed Improvements Notes

Spring Hill Pumping Plant (Raw water pump station)

Structural and nonstructural seismic improvements to the existing structure.

JWC may replace the intake structure and pump station. Replacement would likely be more costly.

Raw water pipelines Replace two raw water pipelines A minimum of one pipeline could be replaced to meet the 42 MGD LOS goals; however, both will be replaced to supply the 85 MGD WTP.

Rapid mix facility New rapid mix facility and yard piping

Flocculation/ Sedimentation Basins

Replace basins A through C with new basins H and I similar to basins D through G

Resilient capacity could also be achieved by adding flocculation time and additional plates to the existing basins D through G in lieu of building new basins.

Filters Replace existing filters 1 through 14 with new filters 17 through 22

A minimum of two more filters are required to provide the LOS goal of 42 MGD. All six filters are needed to fully replace the existing filters.

Clearwell New 2.5-MG clearwell LOS goals could be achieved with clearwell bypass by using Fern Hill Reservoirs for CT with some piping reconfiguration. The existing clearwell is assumed to remain in service with isolation valves for use in the event of an earthquake.

Finished water pump station

Replace FWPS 1 with new FWPS 3

FWPS 2 seismic improvements: structural, including foundation improvements


New washwater and solids facilities New surge and recycle included with 2019 project can accommodate 42 MGD. Additional capacity is required for 85 MGD.

Chemical facilities New chemical facility (alum, polymer, powdered activated carbon)

New onsite sodium hypochlorite generation facility

Operations building New operations and maintenance building(s)

Notes:

CT [chlorine concentration x] contact time FWPS finished water pump station LOS level of service MGD million gallons per day

Figure 7-1 shows the proposed layout of the JWC WTP following completion of the Seismic Resiliency Upgrades for 85 MGD. This project involves adding a new rapid mix facility, flocculation/sedimentation basins, six filters, clearwell, FWPS, surge basin, operation and maintenance buildings, and chemical building. Figure 7-2 shows the process flow diagram for the final configuration following this project.

7.1.2 Capacity The WTP peak capacity will be 85 MGD, because no additional capacity is planned as part of the improvements. Part of the project design evaluation likely will include reviewing opportunities to increase the WTP firm capacity with low-cost improvements during design and construction.


WT1010161153PDX 7-3

Figure 7-1. Layout of Joint Water Commission Water Treatment Plant after the Seismic Resiliency Upgrades to 85 Million Gallons per Day

Figure 7-2. Seismic Resiliency Upgrades to 85 Million Gallons per Day—Process Flow Diagram

Spring Hill

Pumping PlantClearwell

Rapid

mixFilters

M

Flocculation SedimentationFinished water

pump stations

FW

SW

BASIN D

BASIN E

BASIN F

BASIN G

Finished water

(to transmission)RW

RW

RW

48" RW

48" RW

M

Finished water

(to transmission)

FW

FW

FW

BASIN H

BASIN I

River

Waste washwater

(to surge basin)

Solids diversion PS

FW

FW

FW


7-4 WT1010161153PDX

7.2 Project Schedule and Phasing Seismic improvements to the WTP are expected to start sometime after 2026, after the completion of the Willamette Water Supply Project. Because the seismic improvements will include replacing most of the WTP and operations must continue uninterrupted, the new facilities must be built around the existing facilities. One phasing concept is presented below as an example of how this project might be implemented.

During the first phase, shown on Figure 7-3, the majority of the new treatment facilities would be constructed, including the new chemical building, rapid mix facility, flocculation/sedimentation basins, additional filters (17 through 22), surge basin, clearwell, and FWPS 3. These facilities are located to allow continuous WTP operation during construction. During phase two, shown in Figure 7-4, the old surge basins and sedimentation basins A through C would be demolished. Finally, the new maintenance and operations buildings then would be built before demolishing the existing operations building, as shown in Figure 7-5.

7.3 Project Budget Facility improvement costs were estimated for the Seismic Resiliency Upgrades project based on the improvement summary discussed above. A summary of these costs is shown in Table 7-2. The costs are based on full replacement of facilities that are seismically vulnerable as indicated in the 2015 CIP Update (Carollo Engineers, 2015). The costs from the 2015 CIP Update are also included in the table for reference. The costs are substantially different for several reasons:

• The 2015 CIP Update is based on achieving the LOS goal of 42 MGD of seismically resilient capacity. Therefore, the estimate does not include new flocculation/sedimentation or new FWPS. The current Facility Plan considers full replacement of all seismically vulnerable facilities.

• The 2015 CIP Update did not include replacement costs for new filters.

• The 2015 CIP Updated did not include costs of foundation improvements such as piles or stone columns for new facilities such as the filters and clearwell.

• The current Facility Plan includes a larger clearwell (2.5 MG versus 1.5 MG) which was sized to better accommodate the larger WTP capacity.

• The current Facility Plan includes cost for replacement of the chlorine gas with onsite hypochlorite, whereas the 2015 estimate assumed use of bulk sodium hypochlorite which has a lower capital cost.

These project components and sizing should will be confirmed based on future water demands and overall supply resiliency when this project moves forward.


WT1010161153PDX 7-5

Figure 7-3. Phase 1 of the Seismic Resiliency Project Construct new treatment facilities: 1. Construct rapid mix facility 2. Construct

flocculation/sedimentation basin 3. Construct filters 17 through 22 4. Construct surge basin 5. Construct 2.5-MG clearwell 6. Demolish gravity thickeners and

construct chemical building 7. Construct finished water PS 3

Delineated wetland

Figure 7-4. Phase 2 of the Seismic Resiliency Project Demolish existing treatment facilities. 1. Demolish basins A through C 2. Demolish old surge basin 3. Demolish filters 1 through 14 and

FWPS 1 4. Demolish clearwell or leave in

service with bypass

Delineated wetland

Figure 7-5. Phase 3 of the Seismic Resiliency Project Construct new operations and maintenance buildings. 1. Construct maintenance building 2. Construct operations building 3. Demolish existing operations

building Delineated wetland


7-6 WT1010161153PDX

Table 7-2. Project Budget by Process Component

Facility Estimate

(June 2016 dollars)a 2015 CIP Update (2014 dollars)b

Raw water pump station $3,500,000 $840,000

Raw water pipelines $5,700,000 $10,320,000

Rapid mix facility $3,300,000 $2,020,000

Flocculation/sedimentation basins $19,600,000 $0

Filtration $33,600,000 $0

Clearwell $13,100,000 $3,340,000

Finished water and backwash water pumping $23,200,000 $5,890,000

Backwash surge and recycling $2,000,000 $10,470,000

Solids dewatering $0 $0

Chemical facilities and systems $13,200,000 $6,600,000

Operations and maintenance buildings $6,400,000 $3,000,000

General, site, and yard piping Included above $290,000

Total $125,000,000 $42,800,000

a The updated estimates provided are current as of June 2016 and generally prepared as Class 4 estimates with an accuracy in the range of +50 percent to -30 percent of the cost shown. Appendix B describes the cost estimating approach further.


Notes:

CIP capital improvement program

7.4 Project Planning Recommendations The following specific planning activities are recommended before initiating the Seismic Resiliency Upgrades Project:

• Update plant security and conduct vulnerability assessment.

• Evaluate National Pollutant Discharge Elimination System permit for backwash water to allow for more operational flexibility.

• Conduct sustainability study to consider Leadership in Energy and Environmental Design™ (commonly called LEED) or Envision certification and potential incorporation of sustainable design practices.

• Finalize chlorine gas replacement approach.

• Complete architectural programming and update budget costs for operations and maintenance building.

• Finalize seismic mitigation approach and facilities to be replaced.

SECTION 8

WT1010161153PDX 8-1

8Ultimate Interim Expansion Water Treatment Plant Plan

8.1 Project Definition The timeline of the ultimate interim expansion plant buildout is currently undefined. Based on the partner demand projections included in Section 2, the ultimate plant buildoutinterim expansion likely will not occur until after 2040. During the facility planning process, the partners have elected to base Facility Plan ultimate buildoutinterim expansion sizing around a working assumption of an ultimate interim peak plant capacity of 105 MGD, due to the available water rights for the partners at the JWC WTP. This will result in the rapid mix through flocculation/sedimentation basins being capable of producing 108 MGD of capacity to account for losses through the flocculation/sedimentation solids blowdown and filter backwash systems. The raw water pump station should will also be sized for 108 MGD, although the JWC recycles most water lost during the solids-handling process, and the likely typical raw water diversion will be less than 108 MGD but more than 105 MGD. JWC should will consider specific partner requirements for firm and winter sustained capacity before beginning this project to develop specific goals for peak, firm, and winter sustained capacity.

The actual production capacity of the JWC WTP following future expansions after the current expansion to 85 MGD will be determined by the Commission, with support from a future master plan update. In addition to expanding the plant to reach its the interimultimate capacity, the ultimate interim expansion plant buildout evaluation includes potential future treatment processes that may be required to account for changing source water quality or future regulations.

8.2 Project Components Table 8-1 lists the project components included in the ultimate interim WTP expansion facility plan that will be added to the WTP following the completion of the Seismic Resiliency Upgrades Project. Refer to Section 5 and Appendix A for more discussion of these improvements.

Table 8-1. Project Components Included in Water Treatment Plant Ultimate Interim ExpansionBuildout Water Treatment Plant Facility Plan


Raw water pump station New raw water pump station (location TBD) or new raw water pipeline from Hagg Lake

Land acquisition


Construct additional plates in basins D through I

Increased flocculation capacity in basins D through I

Filters Two new filters (23 and 24, 10 total)


Solids dewatering New solids drying bed (bed 6)

New treatment facilities Potential ozone or UV treatment depending on future regulations and/or raw water quality (TBD)

Notes:

SECTION 8 – ULTIMATE INTERIM EXPANSION WATER TREATMENT PLANT PLAN

8-2 WT1010161153PDX

MG million gallons TBD to be determined UV ultraviolet WTP water treatment plant

Figure 8-1 shows the proposed site layout for the ultimate interim expansion of the JWC WTP. This represents the ultimate buildoutinterim expansion of the WTP at 105 MGD with two potential future treatment systems. Figure 8-2 shows the process flow diagram for the ultimate interim expansion of the JWC WTP.


WT1010161153PDX 8-3


8-4 WT1010161153PDX

Figure 8-1. Layout of Joint Water Commission Water Treatment Plant after Ultimate BuildoutInterim Expansion


WT1010161153PDX 8-5

Figure 8-2. Ultimate Water Treatment Plant Interim ExpansionBuildout Process Flow Diagram



Jet injection mixing

Filters Clearwell Finished water pump station

SECTION 9

WT1010161153PDX 9-1

Future Expansion Plan

9.1 Project Definition Similar to the interim expansion, the timeline of the future expansion is currently undefined. This expansion will take place sometime after the interim expansion. The primary goal of this expansion is to provide increased winter sustained capacity to allow for expansion of aquifer storage and recovery (ASR) capacity for the partners. Future expansion facility plan sizing is based on a future plant winter sustained capacity of 130 MGD as required to achieve expected long term water demands and redundant supply to the future Willamette Supply System. This will require the treatment plant to achieve 130 MGD at least 80 percent of the time during winter conditions according to the winter sustained definition in Section 4. This will result in the rapid mix through flocculation/sedimentation basins being capable of producing 135 MGD to account for losses through the flocculation/sedimentation solids blowdown and filter backwash systems. The raw water pump station will also be sized for 135 MGD, although the JWC recycles most water lost during the solids-handling process, and the likely typical raw water diversion will be less than 135 MGD but more than 130 MGD. JWC will consider specific partner requirements for firm and winter sustained capacity before beginning this project to develop specific goals for peak, firm, and winter sustained capacity.

The actual production capacity of the JWC WTP following the future expansion will be determined by the Commission, with support from a future master plan update.

9.2 Project Components Table 9-1 lists the project components included in the future expansion facility that will be added to the WTP following the completion of the interim expansion. Refer to Section 5 and Appendix A for more discussion of these improvements.

Table 9-1. Project Components Included in Future Expansion Facility Plan


Raw water pump station New raw water pumps

Flocculation/sedimentation basinsa

Construct two new basins J and K similar to basins D through I

Increase flocculation capacity in basins D through I

Filtersb Construct six new filters (25-30, 16 total)

Solids dewateringc Construct three new solids drying beds (beds 7, 8 and 9)

a Sizing criteria is based on 45 min flocculation time and 0.30 gpm/sf plate settler loading rate

b Sizing criteria is based on a winter filter loading rate of 7.2 gpm/sf and 8,500 gal/sf UFRV

c Sizing criteria is based on a winter loading rate of 480 lbs of solids per MG and an average winter flow of 120 MGD

Notes:

MG million gallons MGD million gallons per day TBD to be determined WTP water treatment plant

SECTION 9 – FUTURE EXPANSION PLAN

9-2 WT1010161153PDX

A full siting analysis of the future expansion was not performed as part of this facility plan. Note that the Seismic Resiliency Upgrades and Interim Expansion Plan must allow space for additional flocculation/sedimentation basins and filters as part of this expansion. Additional land will be needed for the siting of the new solids drying beds, and it is recommended that the JWC look into purchasing land for this purpose in the near future. Figure 8-2 shows the process flow diagram for the JWC WTP future expansion.

Figure 9-1. Future Expansion Process Flow Diagram

M

M

RIVER SOURCE

FINISHED WATER

(TO DISTR)

FINISHED WATER

(TO DISTR)

BACKWASH WASTE

(TO SURGE BASIN)

SOLIDS

DIVERSION PSBASIN K

BASIN J

BASIN I

BASIN H

BASIN G

BASIN F

BASIN E

BASIN D

RW

FW

FW

BWW

SS

FW

FW

FW

SW FW

FW

FW

FW

FW

RW

RW

RW

48" RW

48" RW

Spring HillPumping Plant

ClearwellJet injection mixing

FiltersFlocculation/sedimentation basins

Finished waterpump station

SECTION 10

WT1010161153PDX 10-1

9References Brown and Caldwell. 2013. Chlorine Disinfection and Chlorine Residual Maintenance Study.

Carollo Engineers. 2008. Joint Water Commission Water Treatment Plant Seismic Evaluation Final Report.

Carollo Engineers. 2012. Water Treatment Plant Expansion Preliminary Design Project - Water Treatment Plant Improvement Projects and Packages.

Carollo Engineers. 2015. Joint Water Commission Water Treatment Plant TM No. 1 Capital Improvement Program Update.

Shannon & Wilson. 2008. JWC Seismic Hazard Evaluation - Fern Hill WTP.

Shannon & Wilson. 2014. Revised Geotechnical Report - JWC WTP Seismic Evaluation.

Appendix A TM 2-9: JWC WTP Facility Plan

Alternatives Analysis

Appendix B TM 2-10: JWC WTP Hydraulic Analysis

Appendix C TM 2-11: JWC WTP Facility Plan

Cost Estimating Criteria

Appendix D TM 2-12: JWC WTP Review of Seismic

Assessment and Approach

Documents

Water Treatment Plant Facility Planjwcwater.org/wp-content/uploads/2015/02/Agenda-Item-6A-JWC-WTP-Facility-Plan-Report_4...This Water Treatment Plant Facility Plan (Facility Plan)