Volume i executive summary

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Volume i executive summary

  1. 1. City of Oak Harbor WASTEWATER FACILITIES PLAN Executive Summary DRAFT March 20131218 THIRD AVENUE, SUITE 1600 • SEATTLE, WASHINGTON 98101 • P. 206.684.6532 • F. 206.903.0419pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Cover_TOC.docx
  2. 2. ASSOCIATED FIRMS This Wastewater Facilities Plan was developed in coordination with:CAROLLO ENGINEERS DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Cover_TOC.docx
  3. 3. City of Oak Harbor Wastewater Facilities Plan TABLE OF CONTENTS Page No.ES.1  INTRODUCTION ....................................................................................................... 1  ES.1.1  Project Need ............................................................................................ 1  ES.1.2  Project Goal ............................................................................................. 1 ES.2  PLANNING AREA CHARACTERISTICS .................................................................. 2  ES.2.1  Service Area ............................................................................................ 2 ES.3  EXISTING FACILITIES.............................................................................................. 2  ES.3.1  Existing Treatment Facilities .................................................................... 2  ES.3.2  Existing Effluent Outfalls .......................................................................... 4  ES.3.3  Existing Wastewater Collection System .................................................. 4 ES.4  WASTEWATER FLOWS AND LOADS ..................................................................... 5  ES.4.1  Flow and Load Projections ...................................................................... 5  ES.4.2  Phasing Scenarios For Growth ................................................................ 7 ES.5  REGULATORY REQUIREMENTS ............................................................................ 8  ES.5.1  Effluent Quality Goals .............................................................................. 8  ES.5.2  Biosolids Management .......................................................................... 10  ES.5.3  Other Environmental Documents ........................................................... 10 ES.6  ALTERNATIVES DEVELOPMENT AND EVALUATION ......................................... 11  ES.6.1  Project Objectives and Evaluation Criteria ............................................ 11  ES.6.2  Preliminary Alternatives ......................................................................... 11  ES.6.3  Initially Proposed Sites .......................................................................... 13  ES.6.4  Final Sites and Alternatives ................................................................... 18 ES.7  PROPOSED ALTERNATIVE................................................................................... 22  ES.7.1  Wastewater Treatment Facility .............................................................. 22  ES.7.2  Wastewater Conveyance System .......................................................... 24  ES.7.3  Treated Effluent Outfall .......................................................................... 24  ES.7.4  Project Phasing Scenarios..................................................................... 24  ES.7.5  Phase 1 Cost Summary ......................................................................... 26 ES.8  IMPLEMENTATION PLAN ...................................................................................... 28  ES.8.1  Financial Analysis Summary .................................................................. 28 CAROLLO ENGINEERS i DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Cover_TOC.docx
  4. 4. LIST OF TABLESTable ES.1  Population Projections ................................................................................... 5 Table ES.2  Current Flows and Loads............................................................................... 6 Table ES.3  Projected Flows and Loads ........................................................................... 7 Table ES.4  Effluent Quality Goals .................................................................................... 8 Table ES.5  Windjammer Vicinity MBR Key Considerations ........................................... 21 Table ES.6  Crescent Harbor North MBR Key Considerations ....................................... 21 Table ES.7  Crescent Harbor North AS Key Considerations........................................... 22 Table ES.8  Phase 1 Capacity Summary ........................................................................ 26 Table ES.9  Total Phase 1 Cost Comparison (in millions)............................................... 28 Table ES.10  City Share of Phase 1 Capital Costs (escalated, in millions) ....................... 30  LIST OF FIGURESFigure ES.1  Study Area, Topography, and Existing System ............................................. 3 Figure ES.2  Growth Scenarios for Phasing ....................................................................... 9 Figure ES.3  Project Objectives ........................................................................................ 12 Figure ES.4  Potential WWTP Sites ................................................................................. 14 Figure ES.5.  TBL+ Analysis of Preliminary Alternatives ................................................... 15 Figure ES.6  Six Sites For Further Evaluation .................................................................. 16 Figure ES.7  TBL+ Analysis of Refined Alternatives ........................................................ 17 Figure ES.8  Windjammer Vicinity Charrette Results ....................................................... 19 Figure ES.9  Crescent Harbor North Charrette Results.................................................... 20 Figure ES.10  Treatment Process Flow Schematic ............................................................ 23 Figure ES.11  Conveyance Improvements for Scenario 1.................................................. 25 Figure ES.12  Estimated Phase 1 Project Costs ................................................................ 27 Figure ES.13  Proposed Schedule ..................................................................................... 29 Figure ES.14  Monthly Sewer Rate Analysis ...................................................................... 31 CAROLLO ENGINEERS ii DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Cover_TOC.docx
  5. 5. City of Oak Harbor Wastewater Facilities Plan TABLE OF CONTENTS Page No.ES.1  INTRODUCTION ....................................................................................................... 1  ES.1.1  Project Need ............................................................................................ 1  ES.1.2  Project Goal ............................................................................................. 1 ES.2  PLANNING AREA CHARACTERISTICS .................................................................. 2  ES.2.1  Service Area ............................................................................................ 2 ES.3  EXISTING FACILITIES.............................................................................................. 2  ES.3.1  Existing Treatment Facilities .................................................................... 2  ES.3.2  Existing Effluent Outfalls .......................................................................... 4  ES.3.3  Existing Wastewater Collection System .................................................. 4 ES.4  WASTEWATER FLOWS AND LOADS ..................................................................... 5  ES.4.1  Flow and Load Projections ...................................................................... 5  ES.4.2  Phasing Scenarios For Growth ................................................................ 7 ES.5  REGULATORY REQUIREMENTS ............................................................................ 8  ES.5.1  Effluent Quality Goals .............................................................................. 8  ES.5.2  Biosolids Management .......................................................................... 10  ES.5.3  Other Environmental Documents ........................................................... 10 ES.6  ALTERNATIVES DEVELOPMENT AND EVALUATION ......................................... 11  ES.6.1  Project Objectives and Evaluation Criteria ............................................ 11  ES.6.2  Preliminary Alternatives ......................................................................... 11  ES.6.3  Initially Proposed Sites .......................................................................... 13  ES.6.4  Final Sites and Alternatives ................................................................... 18 ES.7  PROPOSED ALTERNATIVE................................................................................... 22  ES.7.1  Wastewater Treatment Facility .............................................................. 22  ES.7.2  Wastewater Conveyance System .......................................................... 24  ES.7.3  Treated Effluent Outfall .......................................................................... 24  ES.7.4  Project Phasing Scenarios..................................................................... 24  ES.7.5  Phase 1 Cost Summary ......................................................................... 26 ES.8  IMPLEMENTATION PLAN ...................................................................................... 28  ES.8.1  Financial Analysis Summary .................................................................. 28 CAROLLO ENGINEERS i DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Cover_TOC.docx
  6. 6. LIST OF TABLESTable ES.1  Population Projections ................................................................................... 5 Table ES.2  Current Flows and Loads............................................................................... 6 Table ES.3  Projected Flows and Loads ........................................................................... 7 Table ES.4  Effluent Quality Goals .................................................................................... 8 Table ES.5  Windjammer Vicinity MBR Key Considerations ........................................... 21 Table ES.6  Crescent Harbor North MBR Key Considerations ....................................... 21 Table ES.7  Crescent Harbor North AS Key Considerations........................................... 22 Table ES.8  Phase 1 Capacity Summary ........................................................................ 26 Table ES.9  Total Phase 1 Cost Comparison (in millions)............................................... 28 Table ES.10  City Share of Phase 1 Capital Costs (escalated, in millions) ....................... 30  LIST OF FIGURESFigure ES.1  Study Area, Topography, and Existing System ............................................. 3 Figure ES.2  Growth Scenarios for Phasing ....................................................................... 9 Figure ES.3  Project Objectives ........................................................................................ 12 Figure ES.4  Potential WWTP Sites ................................................................................. 14 Figure ES.5.  TBL+ Analysis of Preliminary Alternatives ................................................... 15 Figure ES.6  Six Sites For Further Evaluation .................................................................. 16 Figure ES.7  TBL+ Analysis of Refined Alternatives ........................................................ 17 Figure ES.8  Windjammer Vicinity Charrette Results ....................................................... 19 Figure ES.9  Crescent Harbor North Charrette Results.................................................... 20 Figure ES.10  Treatment Process Flow Schematic ............................................................ 23 Figure ES.11  Conveyance Improvements for Scenario 1.................................................. 25 Figure ES.12  Estimated Phase 1 Project Costs ................................................................ 27 Figure ES.13  Proposed Schedule ..................................................................................... 29 Figure ES.14  Monthly Sewer Rate Analysis ...................................................................... 31 CAROLLO ENGINEERS ii DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Cover_TOC.docx
  7. 7. Acronyms & AbbreviationsAA annual averageAACE Associate of the Advancement of Cost EngineeringAAF average annual flowAC asbestos cementADA Americans with Disability ActAS Activated SludgeBAF Biologically Aerated FilterBOD biochemical oxygen demandBWF base wastewater flowCBD Central Business DistrictCCI Construction Cost IndexCCP concrete cylinder pipeCDBG Community Development Block GrantCERB Community Economic Revitalization BoardCFR Code of Federal RegulationsCity City of Oak HarborCMP corrugated metal pipeDHAP Department of Archaeology & Historic PreservationDI ductile ironDIN dissolved inorganic nitrogenDMR discharge monthly reportDNS determination of nonsignificanceDO dissolved oxygenDOH Washington State Department of HealthDS determination of significanceDWF dry weather flowEcology Washing State Department of EcologyEDC endocrine disrupting compuondsEFH essential fish habitatEID Environmental Information DocumentEIS Environmental Impact StatementENR Engineering News-RecordEPA Environmental Protection AgencyCAROLLO ENGINEERS i DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Acronyms.docx
  8. 8. Acronyms & AbbreviationsF/M ratio food-microorganism ratioFDA Food and Drug AdministrationGMA Growth Management Actgpad gallons per are per daygpcd gallons per capita per daygpd gallons per daygpd/sf gallons per day per square footgpm gallons per minuteGT gravity thickenerHDPE high –density polyethylenehp horsepowerHPA Hydraulic Project ApprovalHRT hydraulic retention timeIFAS integrated fixed film activated sludgeI/I Infiltration and inflowJARPA Joint Aquatic Resources Permit ApplicationJPA Joint Planning areaLagoon Plant Seaplane Base Lagoon WWTPLOTT Lakehaven, Olympia, Tacoma, Tumwater areaMBR membrane bioreactorMBBR moving bed bioreactorMDNS mitigated determination of nonsignificancemg/L milligrams per litermgd millions of gallons per dayMHHW mean higher high waterMHI median household incomeMLE Modified Ludzack EttingerMLLW mean lower – low waterMLR mixed liquor returnMLSS mixed liquor suspended solidsMM maximum monthMMF maximum month flowMR Marine ReachCAROLLO ENGINEERS ii DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Acronyms.docx
  9. 9. Acronyms & AbbreviationsNAS Naval Air StationNH3 ammoniaNHPA National Historic Preservation Act of 1966NOAA National Oceanic and Atmospheric AdministrationNPDES National Pollutions Discharge Elimination SystemNRDC Natural Resources Defense CouncilNTU nephelometric turbidity unitsNWCAA Northwest Clean Air AgencyO&M Operation and MaintenanceOHMC Oak Harbor Municipal CodeOS Open SpacePBP Planned Business ParkPD peak dayPDF peak day flowPF public facilitiespH chemical balance measurementPHF peak hour flowPIP Planned Industrial ParkPlan Facilities PlanPOTW publicly owned treatment workspp pounds per dayppcd pounds per capita per dayppd pounds per dayPRE Planned Residential EstatePVC polyvinyl chloridePWTF Public Works Trust FundRBC Rotating biological contactorRCP reinforced concrete pipeROW right-of-waySDC system development chargesSERP State Environment Review ProcessSLR solids loading rateSOR surface overflow rateCAROLLO ENGINEERS iii DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Acronyms.docx
  10. 10. Acronyms & AbbreviationsSRF State Revolving FundSRT solids retention timeSTAG State and Tribal Assistance GrantsSVI sludge volume indexTBL+ Triple Bottom Line Plus TechnicalTF Trickling FilterTF/SC Trickling Filter/Solids ContactTIN total inorganic nitrogenTMDL total maximum daily loadTOrC trace organic chemicalTSS total suspended solidsUFC Uniform Fire CodeUGA Urban growth areaUSEDA United States Economic Development AdministrationUSDA-RD United States Department of Agriculture-Rural DevelopmentUV ultravioletUVT ultraviolet transmittanceVFD variable frequency driveVFW Veterans of Foreign WarsWAC Washington Administrative CodeWDFW table 6.8WDNR Washington State Department of Natural ResourcesWSEC Washington State Energy CodeWWTP Wastewater treatment plantCAROLLO ENGINEERS iv DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Acronyms.docx
  11. 11. Executive Summary WASTEWATER FACILITIES PLANES.1 INTRODUCTIONThe City of Oak Harbor (City) must replace two aging wastewater treatment facilities with anew facility that meets modern standards for reliability and performance. This WastewaterFacilities Plan (Plan) describes the proposed alternative for wastewater collection,treatment, and effluent discharge (marine and/or reclamation), in accordance withWashington Administrative Code (WAC) 173-240. Completing the projects recommended inthis Plan will allow the City to provide continued reliable wastewater service to thecommunity of Oak Harbor while protecting and preserving the surrounding environment.ES.1.1 Project NeedThe City’s wastewater system serves approximately 24,000 people within the City and theNavy Seaplane Base. Wastewater is currently treated at two facilities: a rotating biologicalcontactor (RBC) facility near Windjammer Park, and a lagoon facility on the Navy’sSeaplane Base. A project is needed to replace the City’s two existing treatment facilitieswith a modern facility capable of meeting the objectives listed below. Although the existingfacilities are currently able to meet the requirements of the City’s National PollutionDischarge Elimination System (NPDES) Permit, they are not able to provide reliable long-term service for a number of reasons: The existing RBC facility is nearing the end of its useful life. Both the RBC and Lagoon Plants lack the technology to meet increasingly stringent water quality standards, and have inadequate capacity to keep pace with anticipated population growth. Both effluent outfalls have seen major failures; the RBC Oak Harbor outfall no longer functions and the Crescent Harbor outfall is functional but damaged. The area surrounding the Seaplane Base Lagoon Plant was reclaimed as a saltwater marsh in 2009. The lagoons are now surrounded by environmentally sensitive areas and are subject to frequent high water conditions, making expansion or modifications to the new lagoons infeasible.ES.1.2 Project GoalThe goal of this project is to “obtain the highest level of water quality practical whilerecognizing the limitations of the rate payers of the City to fund the improvements.” Specificproject objectives include:1. Providing continued reliable wastewater treatment service;2. Meeting high standards for water quality;CAROLLO ENGINEERS ES-1 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  12. 12. 3. Allowing phased expansion to meet future demands; and4. Delivering construction and operation of a new facility by 2017 in a cost-effective manner.ES.2 PLANNING AREA CHARACTERISTICSThe City of Oak Harbor is located near the northern end of Whidbey Island in IslandCounty, Washington. The United States Navy operates two bases on Whidbey Island: theSeaplane Base located in the eastern portion of the City, and Ault Field which lies to thenorth of the City. The City covers approximately 6,030 acres (9.4 square miles), of which2,820 acres (4.4 square miles) is occupied by the Navy’s Seaplane Base. The City’s UrbanGrowth Area (UGA) includes all of the City of Oak Harbor, as well as unincorporated areasto the north, between the City and Ault Field, and to the south and west of the City. TheUGA represents the vicinity that is likely to be needed to accommodate growth over thenext 20 years.ES.2.1 Service AreaFigure ES.1 shows the study and service areas for this Plan, which includes all of the UGA,encompassing 7,540 acres (11.8 square miles) of land. A Joint Planning Area (JPA) whichincludes areas that may be developed beyond the 20-year planning period is not includedin the study area, as these areas are not expected to require City sewer service within thenext 20 years. An estimated 136 households within the current city limits are not connectedto the City’s sewer system and are using on-site sewer systems. This equates to less thantwo percent of the City’s population. For the purpose of estimating future flows and loads,this Plan assumes that all currently unsewered areas will be served by the City within the20-year planning horizon.ES.3 EXISTING FACILITIESThe locations of the City’s existing wastewater facilities are shown in Figure ES.1. Existingfacilities include two treatment plants, two effluent outfalls, approximately 74 miles of pipe,and 11 wastewater lift stations.ES.3.1 Existing Treatment FacilitiesWastewater flows and loads treated at the City’s existing RBC Plant are approachingpermitted limits, triggering the need for this Plan. Portions of the RBC Plant are over 50years old and have reached the end of their service life. In recent years the City hasexperienced an increasing number of mechanical failures at the RBC Plant, particularly foroutdated treatment equipment that is no longer prevalent in the treatment industry. Variousanalyses completed prior to this Plan have concluded that there is little or no salvage valuein the existing RBC Plant. Due to its age and condition, and an inability to meet futureCAROLLO ENGINEERS ES-2 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  13. 13. /HJHQG 1 *5 (1 ( 6HZHU ROOHFWLRQ 6VWHP :,/621 5 5 /LIW 6WDWLRQV ( ( 95,(6 5 ::73V $8/7 ),(/ 5 ROOHFWLRQ 6VWHP )$..(0$ 5 RQWRXUV LW /LPLWV 7$/25 5 8*$ RXQW $GRSWHG *2/) 2856( 5 52%,1 /1 8*$ LW $GRSWHG *2/,( 5 1 ( +(//(5 5 1 ( 6/$7(5 5 +817 5 526% 5 6,/9(5 /$.( 5 2$. +$5%25 5 ( # Š $,5/,1( :$ 5(6(17 +$5%25 5 +,*+ 32,17 /1267(5 :$ 5(6(59$7,21 5 72 %86% 5 5 3( 2 5 1 ( 6( (/ 67 . ([LVWLQJ /DJRRQ 3ODQW 7+ $9( )HHW 6: 5 :$ $1 3,21(( 72 : 25$ 1 $9 0 ( , / : 6 ($ $ $ %/ ([LVWLQJ 5% 3ODQW 32 UHVFHQW +DUERU 9 /1 9( )257 18*(17 $9( ( // 5 7H[W 2DN +DUERU %221 5 :$7(5/22 5 %$/$ 5 )LJXUH (6 LW RI 2DN +DUERU 6WXG $UHD DQG 7RSRJUDSK :DVWHZDWHU )DFLOLWLHV 3ODQ 0,//(5 5 LW RI 2DN +DUERU
  14. 14. regulatory requirements using installed technology, alternatives presented in this Planassume the existing RBC Plant will be abandoned and demolished.The Seaplane Base Lagoon Plant (Lagoon Plant) was constructed and originally operatedby NAS Whidbey to serve the Seaplane Base. In 1990 the City secured a 50-year leasefrom the Navy to operate the Lagoon Plant. Wastewater flows and loads treated at theLagoon Plant are approaching permitted limits, triggering the need for this Plan. The currentlagoon treatment process does not provide sufficient capacity to accommodate projectedCity growth. A capacity increase at the lagoons will trigger more stringent effluent standardsthat cannot be met with conventional lagoon treatment. Expansion or modification of theexisting lagoons is infeasible due to surrounding environmentally sensitive areas. Due tocapacity limitations, an inability to meet future regulatory requirements, access issuesduring flood events, and surrounding environmentally sensitive areas, alternativespresented in this Plan assume the existing Lagoon Plant will not be used in the future totreat wastewater from the City’s collection system.ES.3.2 Existing Effluent OutfallsHistorically, effluent treated at the RBC Plant was discharged through an 18-inch diametercorrugated metal pipe outfall and diffuser into Oak Harbor, terminating at approximatelyminus 15 feet mean lower low water (MLLW). The diffuser has had a history of sedimentbuildup and blockage. In the summer of 2010 a significant portion of the diffuser was foundto be filled with sediments. In September 2010 the outfall failed and was abandoned. Sincethat time all flow treated at the RBC Plant has been pumped to the Lagoon Plant.Effluent treated at the Lagoon Plant is currently discharged through an 18-inch diameterconcrete pipe outfall and diffuser into Crescent Harbor, terminating at approximately minus15 feet MLLW. The outfall was inspected in October 2010. Several sections of leaking pipeand joints were identified at that time. Portions of the pipe and diffuser will need to berepaired, replaced, and up-sized if the outfall is used as a component of the City’s futurewastewater system.ES.3.3 Existing Wastewater Collection SystemThe collection system was analyzed in previous planning efforts to determine the capacityof the existing network and to identify other issues that would trigger upgrades orimprovements over the next 20 years. The results indicate a maximum peak hour flow of7.9 million gallons per day (mgd) would be generated in the collection system dischargingto the City’s existing RBC plant. Additionally, approximately 2 mgd of peak flow isgenerated on the Seaplane Base. The sum of these peak hour flows (9.9 mgd) provides thebasis for peak hydraulic treatment capacity under current conditions.CAROLLO ENGINEERS ES-4 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  15. 15. Potential capacity limitations were identified in portions of the sewer system, and certainsegments of the existing collection system were identified as being under-capacity forcurrent flows. However, no segments require upgrades in the initial years of planningunless flow from the Navy is routed to existing gravity pipe segments that are near capacity.The timing for collection system capacity improvements is evaluated as a component of thealternatives analysis presented in this Plan.ES.4 WASTEWATER FLOWS AND LOADSInfluent flow is derived from residential and commercial sources that discharge to the City’sRBC Plant, and from the Seaplane Base. There are no significant industrial sources in theCity’s service area. Existing data were analyzed to determine current flows and loads on atotal and per-capita basis. Future flows and loads were projected using current per-capitavalues and estimates for future population that are consistent with the City’s comprehensiveplanning documents.ES.4.1 Flow and Load ProjectionsExisting and projected population data are shown in Table ES.1. Current wastewater flowsand loads are shown in Table ES.2 and project wastewater flows and loads are shown inTable ES.3.Table ES.1 Population Projections Wastewater Facilities Plan City of Oak Harbor Navy Seaplane Year City UGA Sewered(2) Total Base(1) 2000 15,395(3) 4,400 0 19,795(4) 2010 17,675(3) 4,400 0 22,075(4) 2030 23,776 4,400 731 28,907 2060 36,654 4,400 1,637 42,691Notes:(1) Summarized from the City of Oak Harbor Comprehensive Sewer Plan (Tetra Tech, December 2008) Table 3-2.(2) Assumes the UGA is not served currently and will be linearly incorporated into the service area from 2012 through 2060.(3) Total flow minus Navy flow.(4) US Census data (2010).CAROLLO ENGINEERS ES-5 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  16. 16. Table ES.2 Current Flows and Loads Wastewater Facilities Plan City of Oak HarborParameter City TotalFlow, mgd(1) BWF 1.4 1.8 AAF 1.7 2.1 MMF 2.3 3.0 PDF 3.4 4.7 PHF 7.9 9.9BOD, ppd(2,3) AA 3,556 4,127 MM 4,412 5,049 PD 5,556 6,510TSS, ppd(2,4) AA 2,931 3,371 MM 4,153 4,792 PD 7,383 8,373NH3, ppd(2,5) AA 390 487 MM 470 586 PD 596 745Notes:(1) Total flow includes both City flow and flow from Navy facilities. Since the Navy population is projected to remain constant through 2060, the Navy flows are projected to equal 0.37 mgd for BWF, 0.43 mgd for AAF, 0.65 mgd for MMF and 1.23 for PDF.(2) Total load includes load from both the City and the Navy facilities.(3) The Navy BOD load is projected to equal 514 ppd for AA, 732 ppd for MM, and 942 for PD.(4) The Navy TSS load is projected to equal 440 ppd for AA, 638 ppd for MM, and 990 ppd for PD.(5) The Navy NH3 load is projected to equal 84 ppd for AA, 110 ppd for MM, and 128 ppd for PD.CAROLLO ENGINEERS ES-6 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  17. 17. Table ES.3 Projected Flows and Loads Wastewater Facilities Plan City of Oak Harbor 2030 2060Parameters City Total City Total (1)Flow, mgd BWF 1.9 2.3 3.0 3.4 AAF 2.4 2.8 3.7 4.1 MMF 3.2 3.9 5.0 5.7 PDF 4.6 6.0 7.4 8.6 PHF 9.0 11.0 11.4 13.4BOD, ppd(2,3) AA 4,931 5,444 7,704 8,217 MM 6,117 6,849 9,557 10,290 PD 7,704 8,646 12,037 12,979TSS, ppd(2,4) AA 4,064 4,504 7,704 6,789 MM 5,759 6,397 9,557 9,636 PD 10,237 11,227 12,037 16,984NH3, ppd(2,5) AA 541 638 845 942 MM 651 768 1,017 1,134 PD 827 975 1,292 1,440Notes:(1) Total flow includes both City flow and flow from Navy facilities. Since the Navy population is projected to remain constant through 2060, the Navy flows are projected to equal 0.37 mgd for BWF, 0.43 mgd for AAF, 0.65 mgd for MMF and 1.23 for PDF.(2) Total load includes load from both the City and the Navy facilities.(3) The Navy BOD load is projected to equal 514 ppd for AA, 732 ppd for MM, and 942 for PD.(4) The Navy TSS load is projected to equal 440 ppd for AA, 638 ppd for MM, and 990 ppd for PD.(5) The Navy NH3 load is projected to equal 84 ppd for AA, 110 ppd for MM, and 128 ppd for PD.Population projections for the City are based on the City’s Draft Water System Plan. Navypopulation (and associated flows and loads) on the Seaplane Base are assumed to beconstant over the planning period. Future flow and load projections also assume that theUGA will be uniformly incorporated into the sewer service area by Year 2060.ES.4.2 Phasing Scenarios For GrowthThroughout this planning effort, year 2060 flows and loads are used to determine “ultimate”land area requirements for a WWTP that will serve the City’s needs well into the future.Year 2030 flows and loads are used to size and compare alternatives on a capital and life-cycle cost basis. The actual rate of growth of the City’s population, and correspondingincreases in flows and loads, will likely be different than the values used for planning. ToCAROLLO ENGINEERS ES-7 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  18. 18. account for these potential differences, phasing options are developed for the selectedalternative to achieve the right balance between reliable capacity and affordability. FigureES.2 shows the range of growth scenarios used for this analysis. Phase 1 facilitiesproposed in this Plan are based on the moderate growth scenario (approximately onepercent annual growth in City population).ES.5 REGULATORY REQUIREMENTSRecognizing that the City is connected to the waters of Puget Sound via Oak Harbor andCrescent Harbor, the City’s goal is to obtain the highest level of water quality practical whilerecognizing the limitations of the rate payers of the City to fund improvements. A primarygoal of the City is the continued protection of the water quality of the waters in and aroundOak Harbor, thereby meeting the goals outlined in the Puget Sound Action Plan developedby the Puget Sound Partnership for the Cleanup and Protection of Puget Sound.ES.5.1 Effluent Quality GoalsThe City has established the effluent quality goals for conventional pollutants that are morestringent than the City’s current NPDES permit limits. These effluent goals are summarizedin Table ES.4.Table ES.4 Effluent Quality Goals Wastewater Facilities Plan City of Oak Harbor RBC Plant NPDES Lagoon Plant New Facilities Permit Limit NPDES Permit Limit Target / GoalTSS 30 mg/L 75 mg/L 10 mg/L 85% removal 85% removal 95% removalCBOD5 25 mg/L 25 mg/L 10 mg/L 85% removal 85% removal 95% removalTurbidity Not applicable Not applicable 1 NTUChlorine Residual 0.114 mg/L 0.5 mg/L No dischargeFecal Coliform 200/100 mL 200/100 mL 100/100 mLCAROLLO ENGINEERS ES-8 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  19. 19. 4.5 Measured Data Scenario 1, No Growth 4.0 Scenario 2, Intermediate Growth Scenario 3, Comprehensive Plan 3 3.5 2 1 3.0 2.5 2.0 Maximum Month Flow, mgd 1.5 1.0 Notes: 1 1:  Current measured capacity is 3.0 mgd. 2 2:  Capacity required at projected year of startup (2017) ranges from 3.0 to 3.2 mgd. 0.5 3:  Assuming 3.4 mgd of capacity is constructed in Phase 1, years of service  3 (prior to Phase 2) range from 4 to 13 years. 0.0 2000 2005 2010 2015 2020 2025 2030 2035 GROWTH SCENARIOS FOR PHASING FIGURE ES.2 CITY OF OAK HARBOR WASTEWATER FACILITIES PLANpw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Fig_ES_02.docx
  20. 20. Alternatives are evaluated largely on their ability to meet current NPDES permit limits.However, the flexibility to adapt to future regulatory requirements is an important planningconsideration for the City. Potential future NPDES permit limits considered in this analysisinclude the ability to meet nutrient (nitrogen) limits and potential future trace organicchemical (TOrC) limits. While it is not yet clear how Ecology will establish future limits onthese or other parameters, a number of Western Washington municipalities have begun toevaluate future nitrogen removal. In evaluating alternatives for Oak Harbor, the City isconsidering the need to meet a TIN level of 8 mg/L in the future, should these limits beenforced in subsequent permit cycles. Also, the City is interested in technologies that havedemonstrated some ability to reduce TOrC concentrations in treated effluent, such as theMBR process or AS process with an extended solids residence time (SRT).ES.5.2 Biosolids ManagementThe federal document that regulates the use and disposal of sewage sludge is the CFR,Part 503 (40 CFR §503, EPA 1993). Land-applied biosolids must meet requirements in thePart 503 regulations for reducing pathogens and vector attraction. The rule establishes twobasic classes for pathogen reduction: Class A and Class B. The City is consideringalternatives that will meet the 503 requirements for Class B initially, and Class A in futurephases.ES.5.3 Other Environmental DocumentsThe City has adopted the policies of the State Environmental Policy Act (SEPA) byreference (OHMC 20.04.010). A SEPA review will be completed to ensure that there are noadverse environmental impacts from proposed projects. The City will issue a thresholddetermination as to whether significant environmental impact may be expected as a resultof the projects recommended by this Plan. This determination will be sent to Ecology forconcurrence.To be eligible for financial assistance from the State Water Pollution Control RevolvingFund, this Plan must also comply with the State Environmental Review Process (SERP;WAC 173-98-100). The SERP was established “to help ensure that environmentally soundalternatives are selected and to satisfy the state’s responsibility to help ensure thatrecipients comply with the NEPA and other applicable environmental laws, regulations, andexecutive orders.” Other environmental components of this Plan include a BiologicalAssessment (BA) that will be submitted to the Corps of Engineers, as well as documentsprepared in accordance with Section 106 of the National Historic Preservation Act (NHPA).CAROLLO ENGINEERS ES-10 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  21. 21. ES.6 ALTERNATIVES DEVELOPMENT AND EVALUATIONAlternatives presented in this Plan are comprised of three components: 1) a WastewaterTreatment Process; 2) an Effluent Discharge (Outfall) Location; and 3) a WastewaterTreatment Facility Site. At the onset of the Project, the City took a position that all sites,outfall locations, and treatment processes should be considered potentially viable.The project team used a comprehensive process to develop project objectives andevaluation criteria; and to identify and screen alternatives. The process generally consistedof major milestones between December 2010 and August 2012. Community input was acritically important factor in the development, evaluation and selection of alternatives. TheCity began proactively working with stakeholders in November of 2010 and continues tointegrate a high level of community input to implement the proposed alternative.ES.6.1 Project Objectives and Evaluation CriteriaThe City’s 2009 Comprehensive Plan states that the City “…recognizes the value of itsnatural environmental and supports environmental protection and enhancement. Thecommunity recognizes that total preservation may not be feasible in an urban area. Rather,the City should seek to implement environmental goals within the context of plannedgrowth.” To reflect the City’s values, the project team evaluated alternatives for upgradingthe City’s wastewater treatment system considering impacts and benefits of the project tothe community as a whole. The Triple Bottom Line is a commonly used approach thatweighs three areas of cost and benefit: financial, social, and environmental. The category of“Technical” was included in this analysis to address industry standards in related toperformance, implementability, operations, and maintenance. The approach of combiningthese four perspectives is referred to herein as “TBL+”.For this evaluation, each of the four TBL+ categories was divided into three, equallyweighted objectives. City staff meetings, stakeholder workshops, and community interviewswere completed to establish project objectives and evaluation criteria for comparingalternatives. A summary of the TBL+ objectives and criteria is illustrated in Figure ES.3.ES.6.2 Preliminary AlternativesAfter a preliminary evaluation, the City selected two wastewater treatment processes as thebasis for alternatives development: a membrane bioreactor (MBR) process and anactivated sludge (AS) process with tertiary treatment. Analysis of outfall locations was alsocompleted early in the Project. Oak Harbor was determined to be the most cost-effectiveand preferred location, largely to eliminate the risk of impact fees that could be assessedthrough the aquatic land use lease process. Once these decisions had been made, theprocess of developing and evaluating alternatives was focused on selecting a site for theCity’s new treatment facility.CAROLLO ENGINEERS ES-11 DRAFT – March 2013pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/ES.docx
  22. 22. PROJECT OBJECTIVES FIGURE ES.3 CITY OF OAK HARBOR WASTEWATER FACILITIES PLANpw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Fig_ES_03.docx

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