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HomeMy WebLinkAbout5 - Introduction of the Wastewater Treatment Plan (WWTP) Strategic PlanCITYOFBOULDER WATER RESOURCES ADVISORY BOARD AGENDAITEM MEETING DATE: January 22, 2007 AGENDA TITLE: Introduction of the Wastewater Treatment Plant (WWTP) Strategic Plan PRESENTERS: Ned Williams, Director of Public Works for Uulities Robert Harberg, Utility Planning and Project Management Coordinator Floyd Bebler, Coordinator of Wastewater Treatment Randy Earley, Engineering Project Manager EXECUTIVE SUMMARY: The attached draft Wastewater Treatment Plant (WWTP) Strategic plan is presented to the Water Resources Advisory Board (WRAB) for comment and review. The Facilities Plan, prepared in 1990, and the Utility Plan, revised in 2002, were the ]ast planning documents addressing [he WWTP needs. This strategic plan has been prepared to bring the wastewater utility planning documents into the new city master plan framework. The wastewater treatment utility will eventually have a single, utility wide, master plan. This strategic plan is intended to inform the Wastewater Utility Master Plan on issues related to wastewater treatment. The draft strategic plan is based upon existing documents including the Utility Plan submitted to the Denver Regional Council of Govemments (DRCOG), the Community Environmental Assessment Process (CEAP) for the WWTP Liquid Stream Improvements project, the CEAP for the Solids Handling Improvements project (both now in various phases of construction), and updated population projects. This agenda item requests a review of the plan by the Board and comments on how to improve the draft plan. The draft plan will be revised based upon comments and ideas received within the next month and presented to the WRAB at a future meeting, possibly the March meeting, for acceptance. Fiscal Impacts: Budgetary: The plan itself has no budgetary impact. Funding for the first phase of the construction cited in the plan is in place. Additional funding will be required to carryout the second phase of the construction. The Capital AGENDA ITEM # V PAGE 1 Improvements Project (CIP) budget includes $18,500,000 of improvements in 2010. Future funding of additional construction will probably require additional user rate increases. • Staff Time: The impact of the future potential improvements identified on staff time is unknown at this time. Other Impacts: The potential future projects identified in the plan generally improve water quality in Boulder Creek, protect downstream water users or reduce local impacts from the treatment facility. The potential future improvements will keep the plant in compliance with its discharge permit and local requirements. Economic: The future projects could potentially result in unbalanced social impacts because lower income customers would be dis-proportionally impacted by any rate increase. Community: The impacts depend upon the improvements selected. Far example, residents in close proximity to the facility could have fewer odors and noise if noise and odar treatment components are required in future work. Other Board and Commission feedback: The strategic plan is in draft form and it has not been presented outside the city staff to the public or other Boards. Public feedback: None received as yet. Staff recommendation: Staff recommends that the WRAB review the strategic plan and provide comments and questions to improve the document and make it more understandable and useful for future planning. Analysis: In most communities WWTP improvements are driven by growth and regulatory requirements. However, Boulder's growth limitations have minimized the impact of growth as a`driver' of plant improvements. Boulder's WWTP improvements are typically driven by regulatory requirements included in the Colorado Department of Public Health and Environment (CDPHE) issued discharge permit. The discharge permit focuses on reducing impacts of the wastewater discharge to the aquatic habitat and protecting downstream water uses. This strategic plan addresses the improvements to the existing facility required to meet the 2003 discharge permit limits. The plan also attempts to conservatively estimate improvements required to meet more stringent discharge permit limits that will likely be associated with the 2009 permit renewal. The plan presents some future decisions that will be vital to the WWTP facility's continued success in meeting regulatory requirements and the Boulder Valley Comprehensive Plan Goals. The strategic plan demonstrates the approach that has been used to keep the W WTP in compliance with regulatory requirements and meet community objectives. All the potential second phase and future improvements presented here will require a CEAP and, probably, a Boulder County 1041 `Matters of State Interest' review and AGENDA ITEM # V PAGE 2 approval. As previously mentioned, this plan will be incorporated into the Wastewater Utility Master Plan. WRAB can comment on the draft plan either at the Jan. 22 WRAB meeting or by e- mailing comments to earleyr@bouldercolorado.¢ov. This will enable the draft to be edited prior to final presentation at an upcoming meeting in which the WRAB will be asked to accept the draft as a Strategic Plan for the WWTP. The acceptance of the revised strategic plan will move the utility toward conformance with the business plan model the city of Boulder has adopted as a framework for master plans. Attachments • Attachment A: City of Boulder's Draft Wastewater Treatment Plant (WWTP) Strategic Plan AGENDA ITEM # V PAGE 3 G~~Y °t ~u1ry~~ Attachment A: / Draft Wastewater Treatment Strategic Plan ~~ •,~J,:,/~` ~ ~ T~ Executive Surnmary: The purpose of this strategic plan is to document past decisions, the facility today, to present the approach that has been used to reach decisions on process selection and introduce some future decisions that will be facing the utility. To continue to provide the level of service required by federal regulations and match the expectations of the community presented in the Boulder Valley Comprehensive Plan Goals, ongoing improvements to the treatment facility are necessary. This strategic plan wil( be a component of a utility wide Wastewater Utility Master Plan. The City of Boulder's most recent wastewater p(anning documents were the 2002 Utilities Plan and the 1990 Facilities Plan and the more recent Collection System Master Plan was completed in 2003. The City has adopted a new framework for City departmental planning documents since these documents were prepared. The new framework includes a single master plan for each of the three Utilities; Water, Wastewater, and Stormwater and Flood Management. Strategic plans will address the major categories of each utility. For example the Wastewater Utility Master Plan will include sections on the collection system, the treatment system, and water quality that will be informed by strategic plans on those components of the utility. The following graphic illustrates the hierarchy of the City's Wastewater Utility master plans and strategic plans. City Wastewater Utility Planning Documents Wastewater Utility Master Wastewater Water Quality Treatment Strategic Plan 5trategic Plan Wastewater Collection System Strategic Plan The existing treatment facility includes a trickling filter - solids contacting secondary process. This secondary treatment process is being upgraded to an activated sludge process in the Phase 1 improvements project currently under construction. Phase 1 improvements will also include a dissolved air floatation thickener to thicken the solids produced in the activated sludge process and solid handling improvements. These improvements, when put on line in early 2008 will allow the effluent to meet the limits in the 2003 discharge permit. The application of the new limits in the permit has been January 16, ?007 G\`Y of Boulryer Attachment A: Draft Wastewater Treahnent Strategic Plan ~,~},~~. J~ J~ delayed by a compliance schedule intended to allow completion of the new secondary process construction needed to meet the new limits. The Phase 2 construction, currently planned for 2010, will include any process changes needed to meet permit limits in the 2008 permit. Additional, it may include noise and odor control units, a W disinfection system, and solids stabilization (anaerobic digester) improvements. The components of the Phase 2 project are still speculative at this time. The 2008 permit will again drive the facility needs in the Phase 2 project to a large extent. The 2008 permit could contain requirements for nutrient(s), nitrogen and/or phosphorus, removal that would require additional treatment processes that would have to be included in Phase 2 conshuction. The Colorado Department of Public Health and Environment (CDPHE) issues renewed dischazge permits to the city every five yeazs. Federal requirements developed by the Environmental Protection Agency (EPA) are incorporated in the permits. Wastewater contaminates that may be regulated in the future include endocrine disrupters and disinfection byproducts (DBPs). Endocrine disrupters have been shown to past through the plant untreated and DBPs are formed in the disinfection process. Although we aren't sure what the future permit requirements will be, dischuge permits will continue to be the primary driver for wastewater improvements in the future. January 16, 2007 Z Attachment A: Draft Wastewater Treatment Strategic Plan INTRODUCTION Background G..y ~t Bo Wae~ h''" .~'' ~ ~ ~ ~ The City of Boulder 75°i Street Wastewater Treatment Plant (VUW'I'P) is located at 4049 N. 75`~ Street in the SW 1/a of Section 13, T1N, R70W, Boulder County, Colorado. Treated effluent from the W~WIP is discharged to Segment 9 of Boulder Creek The WW'I'P is defined as a major facility and operates under a Colorado Discharge Perniit System (CDPS) perniit (Number CO-0024147) dated February 1, 2003, which expires on January 31, 2008. The WV~'I'P is being upgraded to meet future wastewater treatment capacity demands and new ammonia nitrogen limits that were incorporated in the C~PS permit. The upgrades include improvements to both the liquid stream treatment and solids dewatering processes (Phase 1). The WWTl' improvements currently under construction (Phase 1) will increase the treatment capacity to 25.0 million gallons per day (MGD) on a maximum month basis and provide the capability to reduce ammonia nitrogen concentrations in the wastewater to levels below that required by the 2003 discharge permit. The Phase 1 improvements will also keep the total nitrogen discharge at or below it's current level. January 16, 2007 CITY OF BOULDER 75TH STREET WASTEWATER TREATMENT PLANT Attachment A: Draft Wastewater Treatment Strategic Plan G~r{ ~ B0~'er ,~,~~' ~~ ~ In addition to the liquid stream improvemenu, the solids dewatering process is being improved to handle increased solids from the liquid stream treatment process and to reduce the volu~ of de-watered solids that must be transported from the W WI'P site. It is anticipated that Phase 2 improvemenu will be implemented in 2010 in response to: • more stringent Q'DS dischazge pernut limitations in 2008, • the desire to replace the existing chemical disinfection (chlorine and sulfur dioxide) process with an ultraviolet (iJ~ disinfection process, • and the need to address biosolids stabilization (digester capacit}~ limitations. Pu~ose of Strategic Plan This strategic plan describes how the current W WTP improvexr~enu were selected, how they will establish the City of Boulder as a proactive environmental stewatd with regards to water quality preservation, and how these improvemenu will position Boulder to meet anticipated future wastewater treatment requiremenu. The plan aLso presents: • The curnent W WTP improvemenu and how they conform to Ciry and County policies and goals; • A comparison with historic operations; • The economic impacu of the current WWTP improvemenu; ^ The implementation plan for current improvemenu (I'hase 1); ^ Strategies for x~asuring system performance; and • Anticipated future requiremenu and implementation plan (Phase 2) CLJRRENT SITUATION Meedng the needs of the community The existing W WTl' is not capable of treating wastewater w the level required to comply with the 2003 dischaige permit require~nu for ammonia removal. But the city has been issued a compliance schedule to allow construction of the new unit processes before those limiu go into effect. In addition, the eatisting plant rating for oxganic material" (Biochemical Oxygen Demand) removal is not adequate to treat the increasing organic loads. The existing WWTP capacityis adequate to meet the needs of the existing community; however, it is not adequate to treat the wastewater generated by anticipated population and employment growth in the Boulder wastewater service area. The W~WTP serves the nine sub-communities of Boulder's wastewater utiliryservice area (WU3A) depicted in Figure 1. Jar,,,~y ib, zaa~ 4 Attachment A: Draft Wastewater Treatment Strategic Plan G```I of Baulaer ,''' ~'!y'.~ ~ ~ ~ FiQUre 1. Mav of WUSA Area (WLJSA area denoted by red line _ ~ w rn a'~ ~ Gunbarrel ~\~r a~ ^ ~o a ~~ North Boulder ~ay Road ~ Palo Park ~ VWVf P ' '~ ~ ~ Valmont Road ~o ~ C rossroa s Central Boulder East Boulder Arapaho e Road olorado Universit Southeast Boulder Basel ine Road South Boulder Road South Boulder h~wy `?6 Boulder's population and employment continue to grow with the population expected to reach 128,162 by 2025 based on a revised estimate of Denver Regional Council of Governments (DRC~G) projections. The Boulder Valley Comprehensive Plan (BVQ') population and employment growth expectations are similar. The wastewater treatment planning documents must use DRCOGs population projection when submitting plans and applying for state level approvals for facility improvements. The BVQ' has recently been revised to include population and employment projections through build-out of the service area. The build-out population is expected to be reached in 2030, but no specific year has been assigned to the employment build-out projections. January 16,1007 G~r{ °~ ~~'e~ Attachment A: Draft Wastewater Treatment Strategic Plan ~,~y,~,~~y J~ J~ Thi+oughout the planning period, population and employment esricnates from DRCOG closely follow estunates from the BVQ'. To keep the values consistent with each other, the employment estixnate value from DRCOG in 2025 has been recalculated to reflect the BVQ' build-out projection. The revised values represent a population projection increase of approximately 7,000 people over previous projections for the year 2030 and an employxnent increase of approximately 23,000 employEd persons. Boulder population projections from DRCOG and the BVQ' are shown in Table 1. Table 1. Ponulation Summarv and Pmiection for Areas I& II ( W[JSA) Pro'ected Po ulation Souice 2000 2001 2005 2010 2015 2020 Build Out BVQ' 106,200 109,180 112,160 115,140 118,120 121,100 129,878 DRCOG Anal is -- 106,614' 109,412 112,341' 116,121 119,500' 128,162 lOriginal esamau provided by DROOG zEstimate based on revised BVQ' pmjectioas Employm~ent values and projections from the BVQ' and DRCOG are summarized in Table 2. Table 2. Em lo ent Summa and Pm'ection for Areas I& II WUS Pro'ected Em lo ent Souree 2000 2001 2005 2010 2015 2020 Build- out BVQ' 101,000 109,260 117,520 125,780 134,040 142,300 167,564 DRCOG Anal is - 106,407 111,0621 119,656 125,228 130,7211 155,921 1 Original es[imate provided by DRCOG zEstima[e based on revised BVQ' projections Based on historical values of 102 gallons of wastewater genented per capita per day and 50 gallons of wastewater generated per employEe per day, an additional flow of approximately 1.1 MGD are anticipated as a resuk of the changes in population and employment projections. This also represents an additional loading of approximately 2,130 pounds of five-day biological o~cygen demand (BOD~ per day. This represenu an increase of 4.4% in the design flow and an increase of 7% in BODS design loading. These increases are generally within the range of accuracy of the initial flow and load projections and therefore are considered to have no significant impact on the capability of the upgraded wastewater treatment facilities to handle the projected flows and loads. The eatisting facility is designed to treat 20.5 MGD; however, the projected capacity requirement to meet the 2030 population and build-out employment is approximately 25 MGD. Industrial flow projections are estixnated to be 6% of the total annual flow based on the 2000 and 2001 significant industrial user flows of approximately 0.97 MGD. Figure 2 shows existing WWTP capacity (20.5 MGD) versus projected flows. Jaz,,,~y ib, zoo~ Attachment A: Draft Wastewater Treatment Strategic Plan G.~V ~t Bourae~ and Treatrnent Canacitv 2s --- . ~ 2s b E 24 3 0 w 23 - - ~ ~ 22 3 0 21 ~ -------- --------- x , , 20 ~ - - 19 - -- ~ 18 2000 2005 2010 ZO15 2020 2025 t DROOG buttl Muc. Month F1ow, mgd ((Average bued on population a[ 102 gpcd, cmployment at 50 gpcd, and SIU flow at 6%) x 1.2) -+-- BVCP based M:ix. Month Flow (Rased on Census), mgd ((Average based on population at 102 gpid, employment at 50 gpa~, and SI U flow a[ G°k~) x 1.2) - - -ExistingTreatmentCapadty,mgd II _ ~ , ~i~., . .. ~ ~, :_ ~, i~ ~~ ~~ ° ~ _ _ If population values increase beyond those predicted (as shown in Tables 1 and 2) the VUW'I'P will not be able to provide adequate treatment capacity. In that case, treatment capacity needs will have to be re-examined before the expected build-out date of 2030, and additional expansion of the WWTP capacity may be required before that time. Strengths of Existing Wastewater Treatment System The e~sting WW'IT' liquid stream system includes a"Trickling Filter/Solids Contact" process that has been operational since 1989. The existing system is shown schematically in Figure 3. Over the past 18 years the facility has generally met the demands of City residents, maintained permit compliance, and has discharged satisfactorytreated wastewater, or effluent, to Boulder Creek For clarification, the liquid stream processes treat the wastewater removing ~ontaminates and the solid stream processes treat the solids removed from the wastew~te~.a~d the solids generated by the liquid stream process. Weaknesses of Existing System The two primary drivers motivating the current WWTP improvements (Phase 1) are new ammonia nitrogen discharge limits and increased wastew~ater flow. The existing faciliry, as shown in Figure 3, will be unable to reduce ammonia nitrogen in the wastewater to the level required by the 2003 discharge permit, the rated BOD capaciry is routinely exceeded and it has insufficient capacityto treat the projected wastewater flows. January 16, 2007 '~ G\,Y o~ Bourcyer Attachment A: i Draft Wastewater Treatment Strategic Plan ,~y, %~' ~~ .~ The improvements will allow the WW I'P to treat projected flows and loads through 2030, treat the wastewater to the level required to meet the 2003 discharge pernlit requirements, provide more operational flexibility, and increase equipment efficiency. Fi~ure 3. Schematic of Existing WWI'1' . ~ ~ ~„ ,.. ,.... , . ' Q ,~.,, Q ,,. 4 . . ', _ "Q . ,,. .... `~ ~~~- - F.. ~ ~Q Q' ' 4 , * 4 -t, 4 Q i~ ~ _4 ,. RELATIONSHIP OF THE WASTEWATERTREATMENT IMPROVEMENTS TO CITY AND BOULDER VALLEY COMPREHENSIVE PLAN (BVCP) GOALS Both the City of Boulder and Boulder County desire to maintain their proactive status regarding environmental stewardship. Consequently, they have established goals in the areas of sustainability and environmental quality. By meeting the objectives of the planned process improvements, the Boulder WW'TP will also meet several City and County environmental goaLs. Relevant City and County goals are listed below: • Improving and protecting water quality; ^ Reducing waste by improving recycling and reuse of biosolids; ^ Protecting the general health and safety of plant workers; ^ Meeting future wastewater treatment capacity demands; and ^ Creating a sustainable community through; o Improved energy efficiency, o Minimization of greenhouse gas emissions, o Cost savings, and J;uwary 1G, ?GO' 8 G``y ot Baulae~ Attachment A: /~ Draft Wastewater Treatment Strategic Plan ,~y /` ~~ ~ ~ o Minimi7.ing chemical usage. Improving and Protecting Water Quality The Colorado "303 (d) List" is a list of surface waters within Colorado that are considered "impaired" with respect to the water quality required for their intended uses. The 2000 Colorado 303 (d) List identifies Segments 9 and 10 of Boulder Creek as being impaired for aquatic life due to elevated unionized ammonia. The list identified municipal WW I'Ps and possible non-point sources of ammonia as the cause of impaument. This listing necessitated implementation of an ammonia Total Maximum Daily Load (TNIDL) study, which subsequently dictated the ammonia nitrogen limit contained in the Boulder Colorado Discharge Permit dated February 1, 2003 is in effect until February 2008. Although the pernut does not place limits on specific nutrients, the City of Boulder recognizes the need to put mechanisms in place to ensure that anticipated future nutrient limits can be met with minimal additional construction. The ammonia limit, and potential future nutrient limits, will contribute to the protection of aquatic life in Boulder Creek. Figure 4 presents an image of Section 9 of Boulder Creek and the location of the Boulder WW'I'P. Figure 4. Segment 9 of Boulder Creek and the Location of the Boulder WV~I'P N r °LJ }J ~ '~ "' • \ ~ Longmont ~ /i\ ~ •~ ~ ` % _~ I , l ~ 1 l i~ ~ / ' 't' / d ~ -1' = i'•.~Il;l ~ O~ . ~.. l;? ( ~ Niwot ~ ,' r~ `\ ~, ' ~,, ~ , '~'_ Bi. ~ 0 ~ t , :-ii Rnnldw Rw.nro~~ ' ~y , e~.,~.i ~ ~1 ~ ' ' ii/~. R TP ~ -~.j' ~ Bonlder'Sr4 \~ ill ir~~ : r • SItMl1'I~TP .+. ~;~illl~~~~i ~ ,, ~ J `~•s - ~ ~~ ~ - Erie °~ ~ o e ~' ~ ~ x~o~~~ ~,uu~ ~ ".,oJ 1 il. oul er /, ~~ ~ 1 ~_.ti~ `_ / 0 (> ~~ M)Ane ~ ~. ~ ~ ~, ~ rc,7ti~~ ` - ~]. ~ ~~v~' . Lafayette ~e 4 ~~)iIl 1~ ~`...,. f.k . ~ G ~ ~ M1~, ~~I~ ~g~, aR n ~ ., , ~f '~,~ .~, ~ r , ~1 Selp~flof "- January 1G,'007 G``y of Boulae~ Attachment A: ~~ Draft Wastewater Treatment Strategic Plan ~,~„%~` ~~ , ~ ~ Current improvements to the WW'I'P (Phase 1) will allow Boulder to discharge water of substantially higher qualiry than the 2003 discharge pernut requires, while also achieving no net increase in the total amount of nitrogen discharged to Boulder Cxeek. By complying with permit's limits, the water discharged from the Boulder WWTP will improve the water quality of Boulder Creek to a level that will protect downstream users and support aquatic life. Figure 5 presents WWTP effluent constituent concentrations that must be met to ensure compliance with the 2003 discharge permit. 5. C;urrent ~ttluent Limits tor Jelectect c:onsatuents~~ are basea on 'rEttective until January3l, 2008 "~'"''The ammonia nitrogen value shown is the annual average. Regulatory limits vary monthly and range from 10.9 to 16.9 mg/L. Effective January 25, 2008, the TMDL-based ammonia limits come into effect resulting in a limit of 53 mg/1 for March, the most stringent month. Reducing Waste and Improving Recycling and Reuse The cit~s WWTP represents the one of the biggest investments and efforts the city continues to make ot reduce and recycle waste generated by the city. The upgraded liquid stream treatment processes and the anticipated increase in wastewater flows at the WW'I'P are expected to increase solids production by 25 to 30 percent. The solids dewatering improvements are designed to treat this new volume and to remove substantially more water from the solids than has historically been the case. By reducing the amount of water in the solids, the volume of material removed from the WWTP will decrease by nearly 50%, resulting in reduced hauling costs and associated fuel usage, and disposal costs. Figure 6 presents a comparison of the existing and anticipated volume of biosolids generation as dry tons per day (dtpd). January 16, 20D7 1 p G\`y pt BoWprer Attachment A: Draft Wastewater Treatment Strategic Plan ~~` ,~y, /~` ~'~y ~..~ ~ [in looking at this chart, are we saying that it is "new liquid stream process at buildout" plus "new process with dew~atering improvements"??] Solids generated in the wastewater treatment process will be anaerobically digested, dewatered, and used as a soil amendment on agricultural lands on Colorado's eastern plains. Alternatively, the solids could be used by a private fum on a contract basis for landscape amendments or other uses. Protecting the General Health and Safety of Plant Workers There was no work time lost from on the job injuries during 2005. The planned improvements will provide improved working conditions and reduce exposure to hazardous chemicals. The upgrades will replace old and outdated equipment with newer equipment that will require less maintenance and reduce potential for possible injury associated with operation. This will provide a safer environment for plant workers and for the surrounding neighborhoods and natural areas and will help maintain baseline conditions of zero injunes. Meeting Future Demands The population of Boulder is expected to grow to approximately 128,160 people by 2030 and the number of people employ~d in Boulder to increase to approximately 155,920. The e~cisting facility is not equipped to treat the volume of wastewater generated by this projected growth, subsequently; an increase in treatment capacity from 20.5 to 25 MGD is needed. After the Phase 1 improvements in place, the facilitywill meet these future demands. G~y ot Bou/u'e~ Attachment A: Draft Wastewater Treatment Strategic Plan ~~y,'~ a~ Creating a Sustainable Community Sustainability in wastewater treatment is achieved through resource conservation, recy~ling and waste reduction. Resource consumption will be minim~~pd through proper process selection, use of eneigy efficient equipment, and operational process optimization. Prunaryissues of concern include: ^ Eneigyusage, • Greenhouse gas genention, ~ Cosu, and ^ Chemical usage Energy Usa~e Although the eneigy efficiency of the new plant equipment will be greater than that of the older plant equipment, overall eneigy consumption is expected to nse due to the higher level of treatment provided and the anticipated higher wastewater flows. In evaluating higher level treatment alternatives, additional enexgy usage was considered to be an acceptable tradeoff when evaluated against increased chemical usage. In addition to the criteria listed above, the Gty is incoxponting I.eadeiship in Enetgy and Environmental Design (I.EED) concepts into the design of the new dewatering facility. Facilityupgrades will improve enexgyefficiencyin several ways: • I.ess fuel consumed o The mileage associated with hauling of solids offsite will be decreased by approximately 50%. o The anticipated replacement of chemical disinfection (chlorine and sulfur dioxide) with UV disinfection (Phase 2) eliminates the fuel consuxnption associated with the manufacture and transportation of these chemicals. ~ Electricityconsumed o Improved eneYgy efficiency of newer equipment will reduce energy waste in the liquid stream and solids dewatering processes (however, due to eneigy demands of the new activated sludge process, electrical energy usage is expected to increase~. ^ Energyproduced o Increased production of solids will result in more methane production as wastewater flows increase. January 16, 2007 ] 2 G,,y pt Bo~l~/er Attachment A: ~~ Draft Wastewater Treatment Strategic Plan ,~y-,,%~~1~' '~~ _, '~, ~ y~ Tti Figure 7 presents data on enecgy usage of e~sting system. Fi ure 7. Ene Usage ~ 20000 a 0 .~ v ~ b ~ 15000 - ~ ~. 0 ~ 0 .p ~ ~ 10000 - ~ a C~J a~'n ~. 5000 - ~ W ~ 0 _ , _ ; - ~ Fuel Energy Electricity Natural Gas Consumed'` Produced°~- Consumed~~'~~ Consum~d ~ ^~ (gal) (KWh) (MWh) (NIlVIBtu) yBased on 2004 data; 2005 data represented an atypical year due to digester cleaning '~'~Based on 2005 data; 2004 data not available. Greenhouse Gas Generation The City of Boulder participates in the Cities for Climate Protection Campaign, an agreement between U.S. cities that calls for a reduction in greenhouse gas emissions equivalent to those identified in the Kyoto Protocol. Improvements in energyusage and reduced fuel consumption lower the WW'I'P's greenhouse gas emissions; however increased solids production creates more methane gas, one of the s~ primary greenhouse gases. Costs WW'1"1' operating costs are based on: ^ Fuel consumption ^ Enetgy usage ^ Chemical usage Janu~~y ir~, ~oo~ 13 G`\'9 01 Boura~,~ Attachment A: , Draft Wastewater Treatment Strategic Plan ~~,~y, ~~~ ~`~" .;~`' ^ Equipment costs ^ Personnel costs The improved wastewatertreatment processes will be more efficient in manyways, and therefore, some operational costs are expected to be reduced. A considerable portion of the 2005 budget was spent on repair and rehabilitation work at the e~sting WWTP. In addition, biosolids recycling costs increased by approxirnately 10% and chlorine costs increased by 25% in 2005. Overall upgrades to the treatment process are expected to m;nimi7~ maintenance and repair costs, however, because the new process will be treating the wastewater to a higher level, some additional costs will be incurred. Figure 8 presents various expenditures from the existing W~jU'TP. 8. Summarv of ExistinQ WV~I'P Costs 25 20 ~ ~ 15 8 ~ u5~~ 76 10 .5 ~ h ~ contractor hat~led biosolids loads and an efficiency4 mpg. Chemical Usa~e on The anticipated implementation of UV disinfection, potentially in Phase 2 improvements, will eliminate the need for chlorine and sulfur dio~de chemicaLs. Figure 9 presents actual chemical usage data for the e~usting plant. Ja~~„ry i~, zoo~ 14 Diesel Fuel Utility Usage Chemical Usage Personnel Consumption* G``y o1 Boura~,~ Attachment A: r~ Draft Wastewater Treatment Strategic Plan ,,~y-,%,~~'' '''~ ';fi_ Figure 9. Chemical Usage Data for the Existing WV~I'P - - 600 I 500 ~-. ~ ~ ~ 400 ~ ~ ~ a~ ~ 300 y ~ .~r ~ "ti ~oo ~ i-i ~ ~ V 100 The use of additional chemicals was considered during the selection process. Several alternatives evaluated required the addition of inethanol to achieve nitrogen removal. The chosen process can remove a substantial amount of nitrogen and phosphonis without the need for chemical addition. This is important since it is anticipated that 2009 Q'DS permit dischatge limitations will limit the dischatge of one or more of these substances (Phase 2). HOW THE STRATEGIC PLAN AFFECI'S LIFE IN BOULDER WVUIT' improvements are necessary for the City of Boulder to continue to meet their environmental stewardship goals. By addressing the two main drivers of wastewater treatment improvements, lower ammonia nitrogen limits and increased wastewater treatment capacity, City goals of furthering community sustainability goals and protecting water quality will be met. The improvements represent a proactive, or "action" approach, to improving water quality in Boulder County because they go beyond the minimum required to meet regulatory requirements. A comparison between operation goals met by the existing WW'I~' and the WV~1'I'P after Phase 1 improvements are implemented is shown in Table 3. J~~~:,,>> i~,?oo~ 15 Chlorine Sulfur Dio~de Attachment A: Draft Wastewater Treatment Strategic Plan Table 3. Comparison of WWTP Capabilities G~y ot eowae. !/~%~'''I' ~ Existing WWTP WWI'P AfterPhase 1 Im rovements ~ Meet future ca aci demands X Meet new ammonia limits mPS 2003 X Provide treaunent options for additional nutrient removal X Provide shorter operating tixne iosolids dewaterin X Eliminate chemical use X- Phase 2 Reduce solids handlin X Minimize long-term o rational cosu' X Muiunize ene re uiremenu X Minimizx greenhouse gas emissions X Minimi~r nei hborhood tra{Eic X Provide ade uate odor control X X Muvtniz.e visual im airment X Im rove air uali X X ~ Long-uan operational costs associated with the e~cisting plant would increase due to reoccurring equipment repair and rehabilitation. ZEneigy use will increase based on Pk~ase 1 Improvemenu due to the increased level of treataient provided. Ene~gy savings from more efficient eqwpment and the improved dewatering process will help w offset the greacer ene:gy demand from Luger, more extensive treatment. 30dor controls will be placed on solids processes. The CDI'S perxnit dated February 1, 2003 includes a compliance schedule that allows the City until January 31, 2008 to comply with the new ammonia limiu. The Phase 1 improvemenu are on schedule to be completed and online before that date. A schematic flow diagram of the WV~'TP after imple~ntation of Phase 1 improvemenu is shown in Figure 10. J~~y ib, zom 16 Attachment A: Draft Wastewater Treatment Strategic Plan G\`y ot Baurae~ ,,~~:~:~ ,~ y~_ T~ w. ~cnemanc riow ~,nar~ or rne ~vew w w 1 r ~n:~s~ z Alum ~ ^~ Inlernal ~li~ed Liyuor Rec~~clr InFluent ~ PC Anaerobic Anoxic Aerated SC *>'~'~ _'~' ~ ' 'i-„ ~~~,~ r ~ Prlmary Sludge ^ i~ WAS PRINCIPLES GUIDE APPROACH TO WASTEWATER TREATMENT IMPROVEMENTS As mentioned previously, the primary motivators behind the WWTP upgrades that simultaneously serve City and County goals were: ^ Improving ammonia nitrogen reduction capability, ^ Increasing treatment capaciry, and ^ Improving the dewatering process capabilities to meet increased capacity requirements. Secondary drivers include: ^ Replacing inefficient equipment with newer, improved equipment; and ^ Reducing chemical usage. The City is required to provide adequate treatment capacity and meet regulatory requirements and these upgrades will allow the City to do so. The secondary drivers could be met simultaneously with only moderate additional cost. These improvements optimize the system and establish the City as responsibly proactive by implementing treatment options that improve effluent quality while potentially minimizing future costs. J.~,t~uy i~, ~ao~ 17 G\`y oE Boulae~ Attachment A: ~~ Draft Wastewater Treatment Strategic Plan ~,ky%,%~' ~~ 'w ~ Tti LIQLIID STREAM ALTERNATIVES ANALYSIS As part of the preliminary design evaluation, nine process alternatives were initially considered for upgrading the Boulder 75th Street WW I'P. For more inforn~ation on the original nine treatment options and the selection process refer to the Ciry of Boulder Wastewater Utiliry Plan Amendment 1 and Site Application Report (Brown and Caldwell, 2005). Based on the initial process review the following five alternatives were selected for detailed evaluation. ^ Alternative 3. Trickling Filter - Solids Contact Tank - Nitrifying Trickling Filters - Trickling Filter Recycle - Denitrification Filters - Chemical Phosphotus Removal (TF-SGNTF-TFR DNF) ^ Alternative 6. Trickling Filter - Activated Sludge ('fF-AS) ^ Alternative 7. Activated Sludge (AS) ^ Alternative 8. Trickling Filter - Membrane Bioreactozs (TF-MBR) ^ Alternative 9. Membrane Bioreactor (MBR) These alternatives were evaluated in detail and the results of the evaluations are presented in Figure 13 and Table 4. Basis of Economic Evaluation The economic evaluation includes consideration of initial construction costs and ongoing operation and maintenance (O&N~ costs. It is important to consider both types of costs since some alternatives may be capital cost intensive and yet require minimal annual O&M costs, while other alternatives may be less capital cost intensive but require high annual ~&M expenditures. Present Worth Analysis is a technique used to put construction and O&M costs on a comparable basis so alternatives can be appropriately evaluated. Present worth costs were evaluated over a period of 20 years. Figure 11 shows the results of the economic, or present worth, evaluation of these alternatives. Js„~~.~,y i~, ~oo~ 1 S Attachment A: Draft Wastewater Treatment Strategic Plan Figure 11. Economic Evaluation for Process Alternatives' G``y ot Bourae~ ~ .'~ ~`/~~y~i T~ 70 ._ ^ Total PW O&M Cost ^ Phase 2 PW Consttuction Cost 60 ^ Phase 1 Construction Cost ~ 50 ` a 40 Q 30 _ . ~ 20 - ~ ~ 10 - - Cg ~ , ~- -~ ~ ' Alternative 3 Alternative 6 Alternative 7 Alternative 8 Alternative 9 TF-SCT- TF-AS AS TF-MBR MBR NTF-TFR DNF 1 Values rounded to the nearest hundred thousand dollars. As shown in Figure 11, the most economically feasible alternatives are Alternative 6 (trickling filter-activated sludge) and Alternative 7(activated sludge). Basis of Non-Economic Evaluation Non-economic factors were also considered in the evaluation of the wastewater treatment alternatives. These non-economic factors are particularly important when the economic evaluation indicates similar costs for two or more alternatives (such as the case with Alternatives 6 and 7 as indicated in Figure 13) or when non-cost issues represent a high priority. The non-economic evaluations for the secondary treatment process alternatives are displayed in Table 4. Each non-economic criterion was scored a value between 1 and 5, with 5 representing the highest or best alternative. January 16, 20C7 19 Attachment A: Draft Wastewater Treatment Strategic Plan Table 4. Non-Economic Evaluation for Process Alternatives G`\y ot Bou1a~,~ h'' .'~' ~~ ~ ~ T~ u ~ ~ ~ ~" ~ c ~ ~ • ." ~ ~ ~ ~ ~ '' yJ ~ ~,, a~ ~ , ~ a ~ v ~ ~~ ~ ~ ~ Criteria ~ ~ ~ .., ~ u v~j ~ ... ~ ~. ~ ~--, -d • ~ w ~ ~ o a a ~ ~ , `~ ~ ~ o '~ ~ H w .~ ~ .~ a o ~ a~ ~ a~ • ~ C `'~ ~ ~ ~ ~ ~ v ~ ~ ar W '~ ~ ~ ~ . ~ a~ ~ ~~Q OA ... ~ c ,i '~ u ~ -d ~ °~ 4~. ~ ~ ~ o ~.' i ~'- i V ~ -, ~- , c. i) ~, „~ Alt. 3- TF/SC, NTF, TFR, DF, Q'R 3 4 3 3 5 4 3 5 4 4 38 Alt. 6 - Trickling Filter - Activated Sludge 4 4 4 3 3 4 4 3 4 3 36 Alt. 7- Activated Sludge 5 4 5 5 4 5 4 4 5 4 45 Alt. 8 - Trickling Filter - Membrane Bioreactor 5 2 2 2 5 2 5 1 4 5 33 Alt. 9- Membrane Bioreactor 5 2 3 4 5 2 5 1 5 5 37 Note: A higher score is more favorable. Refer to the City of Boulder Wastewater Utility Plan Amendment, September 2004, for more details on the non-economic evaluation. As seen from the rating inforn~ation presented in Table 4, Alternative 7(activated sludge) was rated the highest overall from a non-economic standpoint. Disinfection Alternatives The Boulder 75`h Street WWTP currently uses chlorine gas to disinfect the treated wastewater. Gaseous sulfur dio~de is used to remove residual chlorine following disinfection and prior to discharge of the wastewater to Boulder Creek. The e~usting chlorine disinfection system has adequate capaciryto meet the needs of the proposed expansion of the 75`h Street facility from 20.5 MGD to 25 MGD, however it does not meet current industry standards associated with the safe handling of chlorine and sulfur dio~de gases (both chlorine and sulfur dioxide gases are considered hazardous chemicals). This, along with a broader concern about the safety aspects of transporting and handling hazardous chemicals and the environmental impacts associated with using chlorine as a disinfectant, prompted the Ciry to evaluate replacing the existing chlorine disinfection system with a different system. Jan~y iv. ?om 2p Attachment A: Draft Wastewater Treatment Strategic Plan The following disinfection alternatives were considered: G\\`I pt BoWae~ ,,~~.~:~ ,~` y~- T~ ^ Alternative 1- Chlorine Gas with Sulfur Dio~ude (E~sting Gasous Chemical System) ^ Alternative 2- I~'igh Strength Sodium Hypochlorite with Sodium Bisulfite (Liquid Chemical System) ^ Alternative 3- Onsite Sodium Hypochlorite Generation with Sodium Bisulfite (Liquid Chemicals System) ^ Alternative 4- Disinfection with L1ltraviolet Light (UV Disinfection) Figure 12 presents an economic evaluation for disinfection alternatives to be used with the activated sludge process. Figure 12. Economic Evaluation for Disinfection Alternatives ~ ~ Construction Cost ^ O&M Cost ~ 6.3 6 - 5.2 5.2 ~-. ~ 5 `~ 3.4 Q 4 - - a 0 3 - .~ ~ 2 - ~ i H U 1 p - , - ~ Gaseous Chlorine F--figh Strength Liquid Disinfection with W Disinfection ' Disinfeaion Sodium Hypodilorite Low Strength Liquid Disinfection Sodium Hypochlorite Generated on Site As shown in Figure 12, the most economical alterriative is continued gaseous chlorine disinfection. The results of an evaluation of non-economic factors for disinfection alternatives is presented in Table 5. January 1G, 2G07 21 Attachment A: Draft Wastewater Treatment Strategic Plan Table 5. Non-Economic Evaluation of Disinfection Alternatives G~~Y ~t Bou1aP~ ~~;, ,'~/,~~` ~';~" ~y'~_`' R ~ a~ ~ ~ ~ ~ a~ a~ ~ ~ ~ ~ ~ ~i l~+' '~ .p" ~" ~? ~ ~ J~'~'' ~ ~ ~ '~'' •~ p~ a i ~ Criteria o ~ W ~ ~ ~ :~ o •°; ~ ~ ' . ~ G~ •~ ~ ~ u ~ O W ~ ~ ~ (~ o ~ Vl ~ V1 ~ ~ ~ ""~ ~ ~ ~ '~ ~ ~ •~ ~y,~ iM r~ ~+ ~ rt '~'~' r.1 h~-1 u ~ Cd a (n rl ~ ~ ~ ~ " ~ ~ ~ •., z ~, °' ~, w ~ on x ~ ~ . o c c Alt. 1- Gaseous Chlorine 5 4 4 2 4 4 4 5 1 3 3 39 Alt, 2 - High-Strength Sodium Hypochlorite 5 4 5 4 4 4 4 4 3 4 4 45 Alt. 3 - On-Site Sodium Hypochlorite Generation 5 4 3 3 4 4 4 3 4 4 4 42 Alt. 4- W 5 3 5 5 4 4 5 2 5 5 5 48 Note: A higher score is more tavorable. UV disinfection was rated the highest of the disinfection alternatives from a non-economic standpoint. UV disinfection is the safest for the WW'IT' staff and the community and it eliminates the need for hazardous chemicals to be shipped to and stored at the WW I'P. UV disinfection is also very easy to operate and maintain, and will allow the Ciry of Boulder to continue to meet their effluent disinfection requirements without the negative aspects of chemical addition. Even though UV disinfection was not the most economical alternative, it was selected as the preferred disinfection method based on the non-economic criteria. Because of funding limitations, replacement of the existing chemical disinfection (chlorine and sulfur dioxide) with UV disinfection is not being implemented as part of the Phase 1 improvement project. It is anticipated this improvement will be implemented as part of the Phase 2 improvements in 2010. Activated sludge and LJV disinfection were selected as the preferred wastewater treatment process to meet Boulder's current and anticipated wastewater treatment needs. Figure 15 illustrate the components of the recommended WWTP upgrades. Jani~ry 16, ?GO? 22 Attachment A: Draft Wastewater Treatment Strategic Plan Figure 15. WW'I'P Upgrades to Existing Facility ~ 5 .tt- ~ w . ~. .~, 'tt ~ ~ ~ tt ` ~,...,b. tt .~ I A x . . . ~ . . . x , . tt tt .... " „~,.,~. ~n ~ ~~ ~ ' ~ -~,~ ° ~~,~~ ~ # Ta ~ J ~ tt ` .n ~ p ~.nw ~i ~n~.v~ ~ ' a^., ' kf K ~+a~.n ~wi . x o M • N Xn .~ ~ Y ~y{`~'d 11 X % i +~ •. ~' r '' j SOLIDS DEWATERING ALTERNATIVES ANALYSIS ~ca~o: +f 08T . PRIIL rv . rn~n ecr • ea[ ec . sECc Hfi . NITRI Cm ~ CIILC MFf . UIBl1 'Three alternatives were evaluated for the solids dewatering process. These alternatives included: ^ Alternative 1: Do nothing ^ Alternative 2: Maintain semi-solid (10-12% solids) dewatering (e~sting process) ^ Alternative 3: Transition to a cake (20-24% solids) product (new process~ The Do Nothing alternative requires no capital investment and neither the operations and maintenance nor the total present worth costs have been estimated. The Do Nothing approach is not a valid selection because the e~sting facilirycannot treat the projected generated solids resulting from the new liquid stream improvements. Alternatives 2 and 3 are based on centrifuge dewatering of digested biosolids produced from the liquid treatment process. Figure 14 presents an economic evaluation of the biosolids G`\y pt Boulae~ ~~. /~ '~~ ~ ~ , . ~, + , . . Y °m'°~ r tt ~TM ~~ + a aai~ i J~„L,~rv i6, ~oo~ 23 ~~ - - G~~y ~t Bou/ae~ Attachment A: /,~ Draft Wastewater Treatment Strategic Plan ,,~y-,%~' ~~ '~ dewatering improvement alternatives. Present worth costs were evaluated over a 20-year period. Fi ure 14. Economic Evaluation for Dewatering Im rovements Alternatives 45 - ^ Total Present Worth ~ 40 ^ O&M Cost ^ Capital Cost .-. 35 ; . ~ 0 30 - A 25 0 ~ 20 + 15 - ~ : ;;..,,.-= _ - ~ 10 - 5 0 - ~- , - Do Nothing^" Dewatered Semi-Solid Dewatered Cake Solid '~Note: The Do Nothing approach is not a valid selection. Table 6 presents a summary of the non-economic evaluations of the dewatering improvements alternatives. J~~.,~y i~, ?co~ 24 G`~ ot BoWtler Attachment A: Draft Wastewater Treatment Strategic Plan ~,~,G~y,JI' J~' ~ Table 6. Non-Economic Evaluation Cxiteria for Dewatering Improvements Altematives Altematives Do Nothing (10-12°k solids) Semi-solid (10- 12% solids) with ewsting solids dewatering building ~ Cake solid (20- 24°~ solids) with new solids dewatering building Description e~usting s}~stem would replace existing ones in existing dewatering building. product and new high-solids centrifugein new building. Advantages Disadvantages • I.ow cosu. • Existing system does not have • No consuuction impacu. capabilityto meet futune WWTP solids loading rate at flows of 25 MGD. • Existing system is 20 yeaxs old and it is difficult to find replacement parts, reducing reliability and plant redundancy. • Would lead to regulatory non- compliance. • Inabilityto store non-dewatered biosolids at lant. • Regulatory compliance. • New centrifuges would be smaller and • Makes maximum use of would be required to operate longer. existuig stnictures. • Structural concems if eatisting building • Sixnilar operation to eicisting are modified again, limited ability to process; staff is familiarwith modifyeausting building. process. • Opinion of probable cost is highest for this alternative due to retrofittmg difficulties, longer run tixnes, more frequent equipment failure, and greater staffin needs. • Regulatorycompliance. • Cake storage is needed. • Makes maximum use of • Requires constnution of new facility. existing suuctures. • Lower biosolids volume. • Fewer truck cosu equal lower O&M costs. • Opinion of probable cost is lowest due to properly sized structure and equipment, reducing staffing and hauling As indicated in Table 6, Alternative 3 represenu more advantages and fewer disadvantages than the other akernatives. Based on the economic and non-economic analysis, the recomnlended improvements for the solids dewatering facility are a new, dewatered cake solid processing facility. January 16, zoo~ 25 _m of BoWp~er G Attachment A: Draft Wastewater Treatment Strategic Plan ~,~},~-;d,~ Jl , In summary, Altemative 3 was chosen because: 1. A cake product is becoming the norm in the industry and produces drier material, which resulu in fewer truck trips from the WIWIT' site. 2. A new dewatexing building is appropriate for the new equipment due to size constraints and age of e~tisting building. 3. Retrofitting the existing facilities would resuk in higher lifetime cosu for the WW'IT'. Cost advantages for consuucting a new building include: a. Installation of properly sized equipment with lower operating cosu, b. I.ower staffing needs, c. Redundant capacity, d. Greater fle~cibility, and e. Lower maintenance costs. INVESTMENT PROGRAM The 2005 Wastewater Utility Capital Improvement Program (QP) developed by the Boulder Department of Public Works includes improvemenu to both the liquid stream and solids stream wastewater treatment process. In December 2005 the C'ity issued a revenue bond to finance the capital cosu associated with the Phase 1 improvemenu. The 2005-2010 Wastewater Financial Plan incorporates a series of multi-year rate increases to cover the cost of the~e projecu. Lhility mte adjustmenu are approved by Gty Council on an annual basis. For 2005 and 2006, the City implemented 20 percent increases to the wastewater user chaYges. An additional rate increase of 6 pe~+cent was implemented on January 1, 2007. Table 7 presenu a comparison of Boulder wastewater rates compared to those of surrounding communities based on 2005 rates. J~„azy ib, zoo~ 26 G~y ot eoube~ Attachment A: Draft Wastewater Treatment Strategic Plan ~y. ~~ ~ Table 7. Front Ran e Communi Sewer Rates' Number Communi Annual Sewer Service Cha e$ 1 Erie 321.00 2 Colorado S rin s 219.29 3 Fort Collins 210.30 4 I.o ont 207.00 5 Greele 195.00 6 Westminster 186.00 7 Broomfield 184.20 8 No lenn 171.00 9 Boulder 170.76 10 Thorntan 163.08 11 I.ouisville 153.60 12 Arvada 148.86 13 Lafa tte 138.84 14 Aurora 130.20 15 Denver 128.16 1 Based on in£oima[ion collected of Front Range Communities conduc[ed in 2005. Investment Strategies Figure 15 depicu the range of investment strategies considered in determining the extent of wastewater treatment system upgrades at the Boulder 75'~ Street W WTP. January 16, 2007 2'] Attachment A: Draft Wastewater Treatment Strategic Plan Figure 15. Comparison of Investrnent Strategies ~ v~s~o~~~ No budget constraints. , Meet all current and fuhice needs initially. ~ected design ~~ ti n Additional hinding with constraints. Meet all curmnt needs and prepate for Futuce growth. Financially constrained. Meet current needs only. G\\y of Bou1a~,~ „~,.: ~%h~': ~ ~ ~ R The City of Boulder chose to pursue an action level approach to wastewater treatment improvements. At this level each area that requires immediate attention has been addressed and mechanisms have been put in place to prepare for anticipated future requirements. Unlike actions taken at the visionary level, the upgrade alternatives were selected to provide the City with the most long term value with respect to cost, system performance, and environmental impact. The system upgrade approach was initially based on two phases of implementation. This phasing approach allows the City to balance capital expenditures by constructing only necessary components in the near-term, while setting the stage for additional process improvements that may be required to meet more stringent future effluent limits. Phase 1 improvements include those that were required to meet current design flows and permit limits and processes that prepare the plant for the Phase 2 upgrades with only moderate additional costs. Phase 2 upgrades include those that are anticipated to prepare the plant to meet anticipated future limits, reduce chemical usage, and treat any odor concerns that may arise. Construction of Phase 1 improvements began in 2006 and Phase 2 improvements are expected to begin in 2010. Phase 1 and 2 improvements are as follows: January 16, 2007 2 g Attachment A: Draft Wastewater Treatment Strategic Plan G\~y pt Boufaer ~~~~=%' ~~ ~ ~ Phase 1(2006): These improvements are required to address the 2003 discharge pernzit limitations (ammonia nitrogen) and to increase the capacity of the WWTP. In addition, these improvements position the plant to meet anticipated future discharge pernut requirements with only moderate additional construction costs. Phase 2(2010): These improvements are anticipated in response to probable more stringent Q'DS discharge permit limitations (nitrogen and phosphorus) in 2008, the desire to replace the e~sting chemical disinfection (chlorine and sulfur dio~de) process with an ultraviolet (LJ~ disinfection process, the need to address biosolids stabilization (digester capacit~ issues. Phase 1 Implementation Schedule Figure 16 depicts the implementation schedule for Phase 1 improvements. The schedule includes the time required for total project implementation, beginning with project approval and concluding with fully operational facilities. Fi ure 16. Pro osed Im lementation Schedule Com oneni 2004 200"s 2006 200' 2008 2009 Ia' uid Stream Im rorements C=t: Conr: ~ppio~-a? • ~~~ ~o DeSi . L' ades \[ar _'OU~ !o Au s: - C•0~ g;d • \Iaich '00 CoS15s~ctio!1 ~oril ~ Q: ro -rsae '_CC"c Denaterin Im ~ozements Ciri• Coucii ~ ro-: a: • X reinbec. 20Q~ Des. . C ade< -o~ember _'~~ ro\o~embec'_ 6 g:d • O tobei. '_~y~G \o-: embe ~006 ro CoasxucCOn a,°1 ~'~n`. The following table presents the current capital improvement program funding for the wastewater treatment projects discussed in this strategic plan. It does not include funding for on-going maintenance projects associated with the WWTP. 2006 2007 2008 2009 2010 2011 Phase 1 - Liquid Stream $47,250,000 $0 $0 $0 $0 $0 Phase 2 - Liquid Stream $0 $100,000 $200,000 $1,000,000 $10,000,000 $0 Phase 2 - $ Biosolids Digester 0 $0 $0 $850,000 $8,500,000 $0 Anticipated Rate Increases for Capital and Other Needs 6% 4% 4% 10% 4% 2012 $0 $0 $0 3% january 16, ZOG7 2O G`,y ot Boulae~ Attachment A: Draft Wastewater Treatment Strategic Plan ,,~.;/~` ~~ J ~ . ~ MEASURING PERFORMANCE City objectives were used as guiding principles for the design of wastewater treatment system improvements and will be used as perforn~ance indicators to measure results from the improvement projects. To accomplish this, a baseline of each indicator must be established and compared to indicatots measured at specific intervals following the completion of improvement projects. Table 8 presents a summaryof suggested performance indicators. Table S. Summary of Performance Indicators City goals Performance Indicator 1. Number of occasions WVi/TP is not in Improving and protecting water quality compliance with permit 2. Nutrient concentration in effluent Reduce waste and improve recycling and Volume of exported solids reuse Improve health and safety of WVUI'P Number of WW'I'P accidents operators Meeting wastewater treatment capacity Wastewater flows demands 1. Amount of Energy use Creating a sustainable community through 2. Amount of Greenhouse gas emissions resource conservation 3. Cost of operating plant 4. Amount of Chemical usage Figure 17 provides an example of how the values of various perforn~ance indicators for the e~sting process might be compared with values for the same indicators associated with the WW I'P performance following the improvements. The expecr~l uzlues firnntlae W[XIIP i~r~r.errrnts a~ n~ sho~cer~ tl~se para~ters mtist l~ Yrx~ritor~l in tlae fisture for ~arison J:~n~~ry i~, zoo~ 30 Attachment A: Draft Wastewater Treatment Strategic Plan Fi~ure 17. Comvarison of performance indicatois 900 ~ - -- i 800 ' - ~ --- 700 ~ - _ - - 600 I 500 i - 400 ~ 300 -- 200 ~ - 100 = ~ O ~ ~- --- - 0 - - ! ~ ~ - - - Z - - Old Process ~ ca • g~ t ~ p ~ --- --- New Process - .~ ~ ~ ~ ~ ~ ~ ~ o ~ ~ ~ .o ~ c o ~ a~ ~ ° ~ >, y Y o ~ ~ ~ _ ~ ~ 8 Z o ~ m c~~ m p ~~ ~ ~ - ~~ U '~'Values vary from 16.9 mg/L to 10.9 mg/L depending on the month PHASE II IMPROVEMENTS G~~y ~t Bou~ae~ '~`~%~', /~ ~`~ ~~ . ~J Tti The existing WWTP has met historical needs by providing adequate treatment capacity and appropriate treatment capability. The VW~'TT' is currently being upgraded to treat additional wastewater flows and meet stricter effluent ammonia nitrogen limits in Phasel. These Phase 1 improvements represent an "action level" position for the City. This position requires that immediate action be taken on items of the most urgent need; capacity requirements and pemut limits, with the incorporation of additional proactive elements based on anticipated regulatoryconcerns, environmental quality, and available funding. Many anticipated treatment challenges can be more cost effectively dealt with during current constniction activities than at a later date. Additional phases of design and construction are expected to follow. Concerns to be addressed for Phase 2 work include: ^ Disinfection system, ^ 2008 discharge pernut limits, ^ Biosolids stabilization (digester capacit~ ^ ~dor and noise J:~uary ib, zao~ 31 G\~y ot Bawae~ Attachment A: /~ Draft Wastewater Treatment Strategic Plan ,,~y-,,%~~ „~~ '~~ ~ Disinfection System Because of funding limitations, replacement of the e~sting chemical disinfection (chlorine and sulfur dio~de) with W disinfection is not being implemented as part of the Phase 1 improvement project. It is anticipated this improvement will be implemented as part of the Phase 2 improvements in 2010. For reasons outlined in previous sections the implementation of an LJV disinfection system is preferred over the existing chemical disinfection process. 2009 Discharge Permit Limits Dischatge pernut limits are revisited everyfive years, and it is anticipated that some level of total inorganic nitrogen (TIl~ and phosphorus removal may be required by future discharge permits. Current construction includes provisions to allow these anticipated future limits to be met with rninimal additional capital expenditure. Biosolids Stabilization (Digester Capacity) Based on current projections, the capaciry of the existing digesters will not be sufficient to adequately stabilize the biosolids for continued land application after the year 2012. The need for additional digester capacity will depend on the actual solids production once the improvements are brought on-line in 2008, whether or not land application continues to be a viable recycling alternative, and the success of privatized composting of the biosolids. These issues will be evaluated over the ne~ct several years prior to any additional capital expenditure. Odor and Noise The Boulder County 1041 pernut stipulates no net increase in either odor or noise from the tijVW'I'P. Although additional control measures are not anticipated at this time, the City will continue to monitor odor and noise in compliance with the permit conditions. After the Phase 1 improvements are operational, the need for additional odor and noise control will be re-evaluated and appropriate steps taken as necessary. E, FUTURE CONSIDERATIONS FOR WAST~WATERTREATMENTNEEDS • •j ` ''M, , •~ Future considerations that are beyond the scope of th~s strategic plan and the current Capital Improvement Program include l~ stringent total inorganic nitrogen (TIl~ and phosphorus discharge permit limits, 2) emerging contaminants and 3) biosolids recy~ling or disposal fle~ubility. Stringent Total Inorganic Nitmgen (TIN) and Phosphorus Discharge Permit Limits Chemical addition and/or additional aeration basin volume may be required to remove additional total nitrogen (7TI~ and phosphorus. If e~remely low.TTN limits are ~ `.. • J~,~~~y~ ib, -'oc' 32 G.`y ot Boulae~ Attachment A: r~ Draft Wastewater Treatment Strategic Plan ,,,Fy,,/~~' ~~ '~ implemented in the future, a tertiary denitrification treatment process may also be required. If extremely low phosphorus limits are imposed, tertiary f iltration may be required. Emerging Contaminants Emerging contaminants includes pollutants such as endocrine disrupting compounds and disinfection byproducts. At present little is known about the significance of these contaminants or appropriate treatment technologies for their removal from wastewater, however, regulatory requirements associated with these contaminants may be adapted in the future. If emerging contaminants removal becomes necessary, public education and additional treatment processes will likely be required. This issue will be evaluated in the future as appropriate. Biosolids Recycling or Disposal Flexibility The current WW'IT' upgrade projects will give the Cary a variety of future biosolids end-use options. These options include maintaining the existing land application program, transitioning to privatized land application and privatized composting. The method of final disposal of the solids generated by the wastewater treatment process is going to be an issued until a long term solution can be reached. Concerns have been raised about whether land application should be used when biosolids contain varying quantities of emerging contaminants. If regulations regarding the end-use of biosolids change, treatment and end- use options will be evaluated. The current approach is to maintain flexibility in disposal options so that the utility is in the best position to respond to regulatory changes and community pressures. Ultimately, the final disposal decision could be dictated to the wastewater permit holders like Boulder through regulatory restrictions. January 16, 20C7 33 G\\y pt Boulae~ Attachment A: r,~ Draft Wastewater Treatment Strategic Plan ~,,~y,,/~'' ~~ ~ ~ STRATEGIC PLAN TO MEET CITY GOALS Figure 18 illustrates how the current WVUI'P improvements and decisions for future consideration are directed toward meeting City needs and goals. The tc~p portion of the figure addresses design elements already incorporated into the WWTP improvements. The bottom portion of the figure identifies additional challenges that must be addressed to continue to meet City goals. Figure 18. Meeting City Needs and Goals Liquid Stream Improvements Dewaterin~ Improvements CONTINUE TO SATISFY NEEDS OF PROACTIVELY DELIVER ON CITY GROWING COMMUNITY GOALS - J~a~,~,y ib, zoc7 34 G~\y ~t Boulp~~r Attachment A: / Draft Wastewater Treatment Strategic Plan ~,,~y,,l~' ~~, ,~ ~ Future Considerations Stringent TIN and Phosphon~s Discharge Emerging Contaminants Biosolids Recycling Per~nit Limits and Disposal Flexibility e~ Jam~ary 16, 200' 3 5 Attachment A: Draft Wastewater Treatment Strategic Plan TRIPLE BOTTOM LINE INDICATORS G\`y of BoWae~ ~~': /~ ~~~ ~ ~ The incorporation of adc~itional treatment processes or biosolids handling methods to meet future regulatory requirements will affect environmental, economic, and social aspects of the community. Figures 19 - 21 illustrate how future decisions may affect the Boulder service community economically, environmentally, and socially. Figure 19. Summary of future decision making on environmental impacts 'GHGs (greenhouse gases) Figure 20. Summary of future decision making on economic impacts Replace chemical Increased capital costs, disinfection system with decreased operadng LJV disinfecdon costs Jam~ary 16, 20C7 3C G\N ot Boulae~ Attachment A: / Draft Wastewater Treatment Strategic Plan ~,;~y,,/~~ ~~ ~ ~ Figure 21. Summary of future decision making on social impacts Additional treatrnent for Improve water quality TIN, phosphorous and for downstream useis emerging contaminants Implement enhanced Greater flexibility for biosolids stabilization boisolids end uses from digester capacity Replace chemical Improve safety of plant disinfection system with workers and reduce W disinfection chemical use and transport SUMMARY The Boulder 75`h Street WW'IT' has historically served the City of Boulder well by meeting regulatory requirements and discharging high quality effluent to Boulder Creek. Improvements at the wastewater treatment facility are rypically driven by state and federal effluent discharge limitations. Phase 1 improvements to the WWTI' were necessitated by the imposition of more restrictive ammonia limits on the discharge and by anticipated growth in the Boulder wastewater service area population. The system upgrades currently under construction include improvement to the liquid stream treatment process and to the solids dewatering process. The liquid stream treatment improvements include converting the e~cisting trickling filter solids-contact process to an activated sludge process. The solids dewatering upgrades include the addition of new dew~atering equipment to reduce the volume of solids that must be hauled from the WW'I~' site. Additional improvements will be required in the future as wastewater discharge and solids handling requirements change. Plans have been made to accommodate these anticipated future upgrades with limited additional capital expenditure. The current improvements meet City goals and establish Boulder as a proactive environmental steward. The costs incurred in implementing the current V~1W'I'P upgrades have been paid through bond sales and increased user fees. ]anu<Uy i6, ?oc~ 3 ~ G\N pi Boulper Attachment A: Draft Wastewater Treatment Strategic Plan ~,~,~-,~,J~ ~`~ ~ The current W WTP improvemenu have been designed with the intent of ineeting current treatment requiremenu and suategically positioning the City of Boulder to economically address anticipated future treatment requirex~nu. The Phase 1 improvements are expected to be completed in 2008. Anticipated future wastewater treatment and biosolids handling improvemenu will be implemented as necessary. REFERENCES Brown and Caldwell. Ma~h 25, 2005. Amendment 1 and Site Application Report (Ma~+ch 25, 2005) to the Catyof Boulder Wastewater LJtilityPlan (November 15, 2002). Boulder County. 2006 Boulder Valley Comprehensive Plan. Brown and Caldwell. March 8, 2004. City of Boulder 75`" Street Wastewater Treatment Plant Upgrades Communityand Environmental Assessment Process (C~AP) Addendum No. 1 March 8, 2004. Rothbe:g, Tamburini & Wmdsor, Inc. May2006. CommunityEnvironmental Assessment Process for 75`~ Street Wastewater Treatment Plant Dewatering Improvements. Jaa~y tb, zoo~ 38