Loading...
HomeMy WebLinkAbout4 - Utility Plan Amendment - Wastewater Treatment Plant Master PlanCITYOFBOULDER WATER RESOURCES ADVISORY BOARD AGENDAITEM MEETING DATE: September 20, 2004 AGENDA TITLE: Utility Plan Amendment- Wastewater Treatment Plant Master Plan PRESENTERS: Randy W. Earley, Utilities Project Manager Robert Harberg, Utilities Planning and Project Management Coordinator Floyd Bebler, Wastewater Treatment Plant Coordinator Ned Williams, Director of Public Works for Utilities EXECUTIVE SUMMARY: The Denver Regional Counal of Governments (DRCOG) reqwred local utilities m the region to provide Utdity Plans documenting wastewater systems by 2003 The city of Boulder submitted a Utdity Plan in late 2002 These Utility Plans were mcorporated into the Metro Vision 2020 Clean Water Plan The intent of the Metro Vision 2020 Clean Water Plan is to increase the effectiveness and effiaency of wastewater management and plannmg in the nine county region of DRCOG Also, the Utdity Plan is used by the Water Quality Control Diwsion of the Colorado Department of Public Health and Environment (WQCD) for site reviews Boulder's plan combmed information from the Boulder Valley Comprehensive Plan, Boulder's Wastewater Collection System Master Plan and the old 201 Faalities Plan including service area, collect~on system and treatment plant data The Utdity Plan must now be amended with information from the new 1041 Permit and proposed treatment plant improvements from the Wastewater Treatment Plant (WWTP) Upgrades Pro~ect preliminary design The amended plan wdl be submitted to the WQCD for review Since the Utdity Plan has all the elements of a master plan for the wastewater treatment plant, the Utdities division would like to have this amended Utility Plan adopted as a wastewater treatment plant master plan The adoption addresses state reqwrements and city planning needs, achievmg both sets of goals with a single planning document This document does not contain new information, it combines information from the Wastewater Collection System Master Plan and the Wastewater Treatment Plant Upgrade Pro~ect Preliminary Design report Fiscal Impacts: Budgetary Approving the UUlity Plan Amendment and using it as the Wastewater Treatment Plant Master Plan would save money and effort by using the AGENDA ITEM #_4 PAGE 1_ Utdity Plan for dual purposes The Utdity Plan and its contnbuting documents have cost thousands of dollars to develop Utilizing this document as the Wastewater Master Plan could save substantial amounts of resources by avoiding duplicate costs Other costs assoaated with the Wastewater Treatment Plant Upgrade do not change as a result of submitting this plan These costs have been identified and rewewed as part of the 2005 budgetprocess Staff Time: The recommended action would save staff time now and reduce future needs by combining the two planning efforts Other Impacts: The additional impacts have been considered in the Wastewater Treatment Plant Upgrade pro~ect Community Environmental Assessment Process (CEAP) and no other impacts are anticipated from adoption of ihis document Other Board and Commission feedback: No additional board or commission feedback is avadable at this time. Public feedback: No public feedback has been received at this time The WRAB meeting, which was publicly announced, is one of three opportunities to obtain public feedback The item will then go to the Planning Board for recommendation and the City Councd for acceptance There wdl be opportunity for public mput at each meeting. It should be noted that no public input was received on the Wastewater Collection System Master Plan during the approval process Additionally, the Wastewater Treatment Plant (WWTP) Upgrades pro~ect, which contains all the alternative analysis and process selection information, has prewously gone through the City of Boulder CEAP and a Boulder County '1041 Matters of State InteresY review Staff recommendation: Staff recommends that the WRAB accept the rewsions to the Utdity Plan and recommend its acceptance by city councd as the Wastewater Treatment Facility Master Plan. Analysis: At the time the onginal plan was submitted to DRCOG, the city had not received a rewsed National Pollution Discharge Elimination System (NPDES) permit Much of the information in the plan was based upon mformation in the existmg permit until the rewsed permit was issued. The rewsed NPDES permit has smce been issued and reqwres construction of treatment plant improvements The Utdity Plan must be amendment to include information from the new permit and the proposed improvements The Water Resources Advisory Board should consider accepting this Utdity Plan Amendment and recommending its use as a wastewater treatment plant master plan to city council It prowdes documentation of future loads and anticipated future discharge limitations as well as a plan to handle those AGENDA ITEM #_4 PAGE_2_ increases. Staff feels it provides all the information required in a master plan document Attachments: Executive Summary, City of Boulder, Wastewater Utdity Plan, Amendment 1 and Site Application Report, September 3, 2004 AGENDA ITEM #_4_PAGE_3_ DRAFT CHAPTERI EXECUTIVE SUMMARY INTRODUCTION The Ciry of Boulder (City) is amending the Wastewater Ualtry Plan (CJtiliry Plan) dated November 15, 2002 to provide updated mformation on permttang issues and proposed unptovements to the City's 75'" Street wastewatet tteatment plant (~X/VV'IP) The key components included m thts amendment to the Uulity Plan axe an altexnauves analysis for the WWTP Upgrade and capacity expansion from 20 5 to 25 0 mtllion gallons per day (mgd) and the completed Site Apphcauon form, unth the xeqwred attachments The Uuliry Plan itself has been xefined and pxovides suppomng mformation on curxent condarons and ptoposed upgrades to the City of Bouldet's 75`~ Street WWTP The C1ty cutrently provldes wastewater service to the follounng mne subcommumttes ' Centxal Bouldec • Crosszoads • East Bouldet ' Gunbarrel/Heatherwood ~ Nozth Boulder • Palo Park ' South Bouldez ~ Southeast Boulder • Univecsity of Coloxado (Ci~ The Uahty Plan is pxovided to sansfy Denvex Regional Council of Govexnments (DRCOG) cequ~ements as well as address the wastewater components of the City's Wastewater Master Plancung process An amendment to the Uulity Plan ts requtred for the City of Boulder's W W"1P upgrade and expansion Tkus UaLry Plan Amendment addxesses two prunary axeas mcludtng (1) the collecuon system contatned witlun the WWTP service azea and potenual axeas fox future unprovements idenafied in the City of Boulder Wastewatet Collecnon System Mastet Plan (WWCSMP), and (2) treatment upgrades for mtrogen removal and WWTI' capacity expansion ~~~~ ~ ~ The City's 75~' Street l'V~X/'IP is cuxtendy opexaung under a Coloxado Discharge Pemut System (CDPS) pexnut, wluch expixes on January 31, 2008 An ammocua total maaumum duly load (TMDL) assessment was developed for the Tn-Basm area m 2002 and was appxoved by the Envixonxnental Protecrion Agency, Region VIII, m 2004 The TMDL mcludes Bouldec Creek Segment 9, wluch receives tceated wastewatex fxom the 75~' St WWTI' It is anacipated that the P\Data\GEN\Bouldes\22054\Ocro6es 2004WUP dmendment\CHAI'1'EA 1 d« 1-1 ~~°'~ DR.AFT ~~~ ~ cuxrent CDPS pemut will be amended by the end of 2004 to incoxpotate acsunonta allocanons (pemut lumts) defined in the TMDL assessment An altemanves analysis has been completed to evaluate xequu~ed treatment upgrades to meet ammonia TMDL requ~ements and capauty expansion requirements Based on Elow pxo~ecuons through 2025, a WW'IT' expansion will be necessary to accommodate the cunent subcommwuty populahon gxowth as well as some new development and cedevelopment Based on DRCOG populaaon and employment pco)ecuons, the WW'IP needs to be expanded from the 20 5 mgd capacity Lsted m the curxent CDP~ pemut to 25 0 mgd A site apphcauon fox the expansion to meet pxo~ected flows and regulatory xequtrements idenufied m the pemut is mcluded in Appendix C POPULATION AND FLOW PROJECTIONS Popularion and flow pro~ecuons did not change from the November 2002 Utility Plan. DRCOG esttmates that the 2025 populanon for the Ciry of Boulder unll be 121,OOQ wkuch represents an addiuonal 14,000 people ovex the next 20 yeazs Although DRCOG's Traffic Analysis Zone (TAZ) Model is a very rehable method fox pro~ecnng populatton gcowth, the Boulder Valley Compxehenstve Plan (BVCP) pro~ecaons aze presented to venfy expected gxowth and the ttnung of the grourth ovex the next 20 yeaxs The BVCP census-based pro~ecuons esumate an adcLuonal 15,000 people by 202Q wluch corresponds reasonably well with the DRCOG eshmates Both sets of pro~ecuons aze pcesented m ttus Uulity Plan, but DRCOG's pro~ecnons pxovide the basis for the pxo~ected Elows and loaduigs to the WW'IP The Ciry of Boulder Plamm~g Department is challenguig the 2000 census populanon The proposed census undercount (appxo~umately 8,000 people) alleged m the challenge is curcendy under zeview by the State of Colocado The State has unhl 2010 to accept or deny the challenge If the challenge is accepted, the populahon and flow pto~ecuons ptesented tn ttus report will be ad)usted when the report is revised m the futuxe Average annual flow pro~ecuons aze based on the above-two descnbed populaaon and employment forecasts (not mcludtng the addiaonal 8,000 people assonated unth the census challenge populaaon) Pro~ected avexage annual flows for populahon and employment are based on lustoncal values of 102 gallons per capita per day (g/c/d) and 50 gallons per employee per day (g/e/d), xespectrvely Indusmal flow pro~ecnons aze esumated to be 6 percent of the total annual flow based on the 2000 through 2001 sigiuficant industnal users flows of approxunately 0 97 mgd Pro~ected 2020 annual avexage flow to the WW'IP is estunated to xange from 19 9 mgd and 20 7 mgd, based on the two sets of populanon focecasts fxom DRCOG and the BVCP, iespecnvely The pro~ected 2025 ma~uxnum month flow is appzo~umately 25 mgd foc both sources P\Uara\GhN\Boulder\22054\Ocrobet 2004WUP Amendment\CHAPTER 1 d« 1-2 DRAFT EXISTING SYSTEMS Cuxrent txeatment pxocesses at the W~~'I1~ uiclude • Screemng • Gnt removal ~~~ ~,,.~.~'~~ ~ • Pnmary sedunentauon ' Secondary treatment employing tncklmg filters and sohds contact bastns (TF/SC) • Nitnficauon in a nimfying mckhng filtex • Chlonnaaon and dechlonnaaon An on-site labotatory enables the City to analyze tnfluent and effluent watet quality on-stte Approaumately 90 pexcent of the tlvckened biosohds from the W W'I'P are trucked to farm sites m Eastem Adams County and apphed to the land as a ferhhzer and soil amendment The apphcaaon sites ace located appto~umately GO xntles from the WWTP Appxoxunately 10 petcent of the annual biosoLds pxoducrion is composted m Golden, Colorado A new composung faciltty is cutrendy under considecauon by the City and a final deasion on whethec to move forwazd wtth the composung faciliry is antiupated m mid-2005 If a decision is made to move forwaxd unth the composnng pro~ect, u could be completed by the end of 2007 The Ciry of Boulder updated their Wastewatex Collecaon Systexn Master Plan (WWCSMP) m July 2003 Pnor collecuon system mastec plans were completed m 1972 and 1978, and 1983 The City's wastewatex collecaon system contuns pnmanly gxavity sewexs xanging from 4uiches to 60-inches m dtametex These sewets collect and convey wastewater from tesidennal, commerual, and mdusmal sources to the WW 1'P There is one pumpmg stauon and force mazn in the Ciry's collecnon system The City curcendy has two service agreements unth non-Ciry wastewateT sezcnce providers These agreements are wtth the Sombxero Ranch (also known as the Reserve), dated Septembei 1976, and the Hoover Hills Sanltauon Distnct, dated October 1968 RECOMMENDEDIMPROVEMENTS WWTP Upgrades At the ume of the uuual Boulder Wastewater UnLty Plan subnuttal (November 2002), the City was not proposing a ma~ox treatment plant expansion The City wanted to watt far the final Tn-Basin aininoma TMDL and issuance of the new dischazge pemut before mmanng plamung for system upgrade and expansion P\Data\GEN\Boulder\22054\October 2004WOP Amendment\CHAP1'ER 1 d« 1-3 DR.AFT ~~~ ~ A new WW'1'1' CDPS dischaxge permit was issued m 2003, wtth an effecave date of February 1, 2003, but it did not include the TMDL ammoma luxuts The proposed upgxades hezem ace based on the TMDL denved aminoma pemut Lmits, curcent CDPS peznut xequtxements, and addiuonal capaary to address future grourth pxo~ecnons Design of the pxoposed WWTP upgcades ts cutrendy in progress An analysis of upgrade altemaaves is pxescnbed m Chapter G Tlus analysis addresses the pcoposed WW'IP upgrades and capacity expansion to 25 0 mgd A Site Apphcauon for tl~e proposed W W'IP upgxades and expansion, along unth the xequ~ed attachments, is also included Recommended System Improvements As part of the alternauves analysis, iune imual ptocess alternauves were considexed for upgradtng the City of Boulder 75th Street WWTP to meet cuxtent and annupated future loadmgs and effluent lunlts The altemanves weie evaluated based on two phases of unplementaaon Tlvs phasmg approach allows the City to balance capital expenditures by construcung only necessary components m the near-texm, such as those to addxess mmficauon reqmrements and plant capacity needs, wtule plannmg to accommodate addtuonal pxocess facilmes that may be xequtred to meet more smngent futute efEluent hmtts and potenaal addiuonal regulatory requ~sements Construcnon of the Phase 1 tmptovements 1s expected to begin 1n 2005 These unpxovexnents aze the basts fot the \X/VV'TP upgtades proposed m tlus Uttltty Plan Amendment Phase 2 unpxovements, tf xequtred, axe expected to occur m 2010 or 2015 The phasmg is dnven by capacity xequtxements and anuctpated efEluent Lmits The Phase 1 unpcovements will lay the fraznework foc the potennal futuxe Phase 2 addmons Phase 1 and 2 unprovements aze as follows Phase 1(begui tn 2005) Phase 1 genetally includes neaz-term unprovements such as those tequtred to addtess capaaty constraznts and hydtaulic botdenecks, and process changes necessary to meet estabhshed TMDL ainmonia limits The faahues included m Phase 1 unll meet e~usung effluent luruts, including total suspended sohds (TSS) and biochemtcal o~cygen demand (BODS) and TIvIDL denved aimnocua limtts as well as pxovide 25 mgd of treatment capacity based on average daily flow for the maa~mum 30-day flow penod The Phase 1 design also considexs the footpnnt requuements for future xegulatory dnven unprovements anaapated foc Phase 2 Phase 2(begln tn 2010 or 2015) Phase 2 includes conttnued treatrnent at the Phase 1 level plus the addtaon of pcocesses and/or chemical addtaon facilmes requtred to meet potenual future effluent Lmits for mteate or total moxgamc nitrogen ('I'IN) and phosphorus Although these future Lmits ace not defined at tlus nme, it is anaupated that lmvts for mtrate or TIN and phosphorus could occur wttkun the next two pexrrut cycles P\Data\GEN\Boulde[\22054\October2004Vf/UPAmendment\CFiAP7'ERid« 1-4 DRAFT o~"' ~ '.~~~=:~~ ~ Based on the evaluauon suminanzed m Chapter 6, convexsion of the e~usnng FF/SC process to acavated sludge (Altemauve 7) is the preferxed wastewatec tzeaunent system to meet Boulder's curxent and anuupated wastewater treaanent needs Acuvated sludge has a lower pcesent worth cost and is also moce appealuig fxom a non-economical standpoint than any of the other altexnaaves available The cecommended unpzovements genexally include • Construcaon of acttvated sludge aexauon basms and ur supply faciliaes • Construcnon of one addthonal secondary clanfier wtth return acuvated sludge pumping upgrades ' Demohuon of one e~sung mckl~ng filtec • Constcucnon of UV dismfecaon facilmes • Construcaon of sohds tluckenmg facility to handle waste acnvated sludge • Other miscellaneous system unpxovements These unprovements are bneIly descnbed below Construct~on of Aecauon Basms and ?ur Supply Facilities (Acuvated Sludge). Aeration Basins - Phase 1. Two 100' x 180' x 24' aeraaon basins are assumed for Phase 1 The two basms have a combined volume of 6 5 milhon gallons Tnckling Fdter (TF) 4 wtll be demohshed and the Phase 1 aerauon basms will be constructed m its place In Phase 2, TF 3 would be demol~shed and one addiaonal aexatton basui would be constructed Dewatenng, excavanon, shonng, backfill, and concrete wotk wtll be xequtted Anttupated eqiupment includes staznless steel aexauon ptpmg, dtffusers, xruxers and shde gates The e~usung secondary puxnpmg staaon will be modtfied to pump to the aexauon basm mEluent channel Replacement mEluent hft pumps and pipmg unll be zequtted An efEluent channel to caxry aerauon basm effluent to the e~usung soLds contact tank influent channel will also be required Aeration Basins - Phase 2.. One new aeraaon basin would be constcucted foz Phase 2 wFuch would be idenucal in size to those constructed m Phase 1(each tank @ 3 25 MG) Constcucuon of tlus future basin will reqwre the demoLnon ofTF 3 Blower Buildtng. A new blower builduig with dunensions of 80' x 55' and sized for thxee or four blowexs will be xeqwxed fox Phase 1 No expansion of the builcLng or mstallaaon of addmonal blowers will be requtred for Phase 2 Secondary C1anSer/Return Activated Sludge Pumping Upgrade. One addmonal 110-foot diameter secondary clanfier wtll be requtxed fox Phase 1 along with modificatton to the e~ctsung RAS pumping facilmes The five e~usung 4 4mgd puxnps unll be xemoved and replaced wtth 6 new 6 25-mgd puxnps In addtaon, a scum pump, WAS pumps, and mixed hquor and RAS piping will be requ~ed P\Data\GEN\Boulder\22054\Ocrohei200¢WUPAmendment\CHAPTCRidoc 1-rJ DRAFT ~~ °' ~+~, ~ ~ Demolition. The aeraaon basms for Phase 1 will be constcucted where TF 4 ts curxently located In addinon, the e~sttng scmbber building located between T'F 2 and TF 4 unll be demohshed to accommodate aeraaon basin construcaon m Phase 1 Construcuon of the Phase 2 aexanon basm will xequtxe the demohaon of TF 3 iJV Dismfection. Phase 1 mcludes installanon of an LTV dismfecuon system m the e~usung chlonne contact basin An enclosuxe for the iIV dtsmfecuon system will be provided to make xouane muntenance moxe convenient, espectally dunng mclement weather A back-up genexatox ox othex secondary power supply will also be provtded The UV system will be designed to treat a peak flow of 56 6 mgd at a dose of 35 mJ/cmZ Sohds Thickening Facility Improvements. Phase 1 will include construcuon of two cLssolved air flotauon ttuckeners (DAFTs) to co-tkucken pntnary sludge and WAS fcom the secondary clanfiecs The e~sung gravity tkuckeners will be converted to DAFT ucuts A new builduig will house the recycle/saturaaon system, polymer system, pipmg, and sludge pumping faciliues Other Treatment System Improvements. Other system unpcovements may include laboratory unpxovements and other items such as lab equtpment, etc Additional Near-Term Improvements. Neax term unprovements idenafied in the Novembex 2002 Unltty Plan axe presented below unth updated pxo~ect status The City of Boulder Caprtal Improvement Program (CIP) covers a 6-year ume penod and is updated annually Improvements hsted in the CIP, and proposed unprovements foc 2002-2004, are as follows Conversion from chlonne cLsinfecuon to ultraviolet Lght dismfecaon Tlus pxocess change is mcluded m the WWTP upgxades cucrendy undenvay An alternauves analysis fox tlus pxocess change is presented m Chapter 6 Relocanon of the 75`~ Stteet W~X/'IP's effluent outfall ~pehne The eausttng W~~1TP outfall was relocated downstreaxn ftom tts cutrent locahon to a new locanon dtrecdy below 75~' Stceet The outfall was relocated m accordance wtth the Interlocal Agreement betcveen the City of Boulder and the City oELaEayette to allow Lafayette to wtthdxaw water from Bouldex Creek above the City of Bouldex's 75`~ Street l'VW'IP point of dischaxge Construcuon was completed in spnng 2003 Construcuon of a Class A biosohds composung facilitv The City's Uulihes Department purchased approac~xnately 35 acres of land for construcnon of the composnng and othex facilittes and is m the process of anne~ung the site A final deasion on whether to move fotward unth construcaon of tkus facility will occur m nud-2005 If approved the pxo~ect may be completed by the end of 2007 The prehinmary plan is to eithex truck tkuckened biosohds or pipe untluckened biosohds to the composnng facility site and compost the matenal wtth wood wastes collected fxom City residents P\Data\GEIY\Boulder\22054\October2004WUP Amendment\CHAPT'ER 1 d« 1-6 DRAFT ~~'~~ .,- ~~ `4~ Imocove the biosoLds handhngand dewatenng~rocess at the W\X/"IP One unpxovement will entatl etthex zettofithng the e~usting biosohds cenmfuge faciliry with lazger, kugh sohds cenmfuges ox bwldtng a new cenmfuge facility at the srte of the planned biosohds compost faciliry Tumng for the pro~ect, in pazt, will depend on the schedule for composnng facility constcucuon P\Datn\GEN\Boulder\22054\Octobei 2004WUP Amendment\CHAP7'ER 1 dw 1-7