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HomeMy WebLinkAbout04.a. Update for Solids Handling Facilities Improvements, Phase 2; DP 100030Page 1 of 32 Item 4.a. F.1-448�411C-S 0 July 10, 2023 TO: ENGINEERING AND OPERATIONS COMMITTEE FROM: MICHAEL CUNNINGHAM, ASSOCIATE ENGINEER NITIN GOEL, OPERATIONS OPTIMIZATION DIVISION MANAGER REVIEWED BY: EDGAR J. LOPEZ, PROVISIONAL DIRECTOR OF ENGINEERING AND TECHNICAL SERVICES GREG NORBY, DEPUTY GENERAL MANAGER ROGER S. BAILEY, GENERAL MANAGER SUBJECT: RECEIVE UPDATE FOR THE SOLIDS HANDLING FACILITIES IMPROVEMENTS, PHASE 2, DISTRICT PROJECT 100030 Attached is the interim project summary and presentation for the Solids Handling Facilities Improvements, Phase 2, District Project 100030. Strategic Plan re -In GOAL TWO: Environmental Stewardship Strategy 1 - Achieve compliance in all regulations, Strategy 4 - Identify and advance sustainability initiatives, including reducing energy usage and emissions GOAL SIX: Infrastructure Reliability Strategy 1 - Manage assets optimally, Strategy 2 - Execute long-term capital renewal and replacement program GOAL SEVEN: Innovation and Agility Strategy 3 - Be Adaptable, resilient, and responsive ATTACHMENTS: 1. Interim Project Summary 2. Presentation July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 12 of 45 Page 2 of 32 100030 I CENTRAL CONTRA COSTA SANITARY DISTRICT Proposed Fluidized Bed InGnerator FaGlhy F wre uv Ilk- �Ak I BACKGROUND 1 PROECTAPPROACH 2 DRIVERS 3 REGULAJORYASSESSNENT 4 SOLIDS END -USE MARKETASSESSNENT 5 ARIIiNMIVES 6.11 DEVELOPMENT OF ALTERNATIVES 12 PROJEI'T CRITERIA 13 GREEN HOUSE GASES AND CAP AND TRADE 14 COST DEVELIOPMENT 15 BENEFIT SCORING 16-17 BENEFIT COST RM10 18 MOVING FORWARD: DIGESTION AND/OR INCINERMON 19 MOVING FORVIWRR FURTHER PROCESS AND PROJECT REFINEMENT 20 PHASING E%9uii 010N 21 PEER REVIEW PROCESS 22 SITE LANOIJT 23 LONG-TERM SOLIDS STRAaTE('aY 24 2 July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 13 of 45 1 Page 3 of 32 Central San's existing multiple hearth furnaces (MHFs) have reliably converted solids from wastewater treatment to ash for more than 45 years. Resource recovery through steam generation from waste heat and beneficial ash reuse (including phosphorous recovery) are consistent with Central San's vision to be an innovative industry leader in environmental stewardship and sustainability, while delivering exceptional service at responsible rates. The MHFs are aging and much of the support equipment is beyond its useful life. The Solids Handling Facilities Improvement Project Phase 1A#7348 will address immediate needs by replacing support equipment, seismically reinforcing the building to protect staff and assets, and upgrading air pollution control equipment to comply with air regulatory requirements. The Solids Handling Improvement Phase 2 updates Central San's long-term solids strategy. When complete, this planning project will identify the future solids handling process to ultimately replace the multiple hearth furnaces and develop a phasing plan to maximize the value of existing assets while starting Phase 2 construction early enough to ensure a smooth transition. PROIJECr APPROACH A five -step process was developed to progress through the Phase 2 evaluation. Updated design criteria were identified based on revised population and loading projections. A market assessment, keeping viable beneficial uses in mind, was conducted to identify the potential uses, users and costs for the final solids product from the various solids treatment altematves. Capital and O&M costs and benefit scores were developed to compare alternatives. The alternatives with the highest Benefit/Cost scores are being further evaluated for phasing. The long-term strategy will recommend the path for the eventual replacement of the multiple hearth furnaces. 'il 7"for Identified end uses sludge after load updates solids handling treatrnent (i.e anently ash) evaluation ,. FbU1e4ed regional costs and rrkt trends s T Furler refinement of hest scoring alternatives and of alternatives consideration Evaluated serif of when to start alternatives in Rreye 2 tesgi more detail and Ca sUt ction Inmrorated peer reviewaormrers rev e Advarced test scoring alteratives to phasing evaluation A© • Updated longbam strategy July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 14 of 45 Page 4 of 32 The 2017 Comprehensive Wastewater Master Plan recommendations for solids treatment process were driven by the need to upgrade or replace aging equipment and structures, meet more stringent air emissions requirements, and process future solids loadings that were projected to exceed the existing furnace's capacity. Subsequent evaluations determined that incineration capacity would not be critical for almost 30 years, but confirmed the regulatory and aging infrastructure drivers for upgrades and eventual replacement. With the Phase 1A project meeting the immediate drivers, the Long Term Solids Facility Plan drivers for Phase 2 became: (LD4� WD (DU C*V) Provide reliable operation while Future facilities accommodate maximizing value of existing assets expected population growth through until the end of useful life. the 30 year analysis period or 2052 (prior plans covered through 2035), including impacts from potentially modifying the liquid treatment process for nutrient removal. W IYE„ Limitations for PFAS in drinking water, effluent, and solids are being considered by regulators. Although research has not yet definitely proven if any processes destroy PEAS in wastewater sludges, testing for a BACWA study measured no detectable PFAS in incineration ash and did measure detectable PFAS in non - thermally treated sludges. The Water Research Foundation is coordinating industry -wide research to quantify PFAS transformation or destruction in incineration and the Water Environment Federation is managing a similar study on pyrolysis. Definitive results are expected over the next one to two years, well before a Phase 2 project would be constructed. Other potential regulatory triggers associated with emerging contaminants are currently considered speculative. The State of California continues to progress regulations associated with GHG emissions, and air regulations may become more stringent over time. The Phase 1A project includes air pollution control equipment necessary to keep the multiple hearth furnaces (MHFs) in compliance with the regulations for older incinerators. The MACT 50 rule requires more stringent air emission limits be met when the cost of all upgrades to the MHFs exceeds 50 % of the original installation cost (inflated to current dollars). Potentially, the Air Board could require that the old MHFs meet standards for new incineration equipment. All Phase 2 alternatives that include incineration have been developed to meet the new limits. Consider current and future llb� nxmaK provide steam for regulations (air emissions, solids end aeration blowers and recycle nutrients product quality and reuse). through the reuse of the solids end - product (currently ash). Maximize use of the available Landfill Gas. Supply is expected to decline overtime. Improve efficiency by reducing labor, maintenance, chemical and power costs. fleainrise gas errFaue remain below California Air %sources Board Cap and Trade inclusion threshold of 25,000 metric tons per year of anthropogenic greenhouse gas emissions. Existing multiple hearth furnace July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 15 of 45 Page 5 of 32 The market assessment demonstrated that ash as the solids treatment end product continues to be advantageous for Central San. There are multiple outlets for beneficial reuse of ash and it is currently the lowest cost end use. Central San is the only Bay Area producer of ash. Most other treatment plants produce biosolids (treated sewage sludge that meets the EPA requirements for land application and surface disposal). If Central San were to produce biosolids for land application instead of ash, Central San would be competing for local sites. The competition for land application sites is increasing with San Jose about to discontinue landfill disposal and move into the land application market. Three counties, Solano, Sacramento and Merced, receive much of the Bay Area produced biosolids. Other counties receiving smaller fractions include Napa, Sonoma, Stanislaus, and San Joaquin. 46% All other Bay Area WWTPs 10% EBVUD 8% Percentage of Bay Area biosolids produced by entity ALTERNATIVES EVAWATION The methodology used to identify, screen, and evaluate alternatives for long term solids processes was similar to, and built on, the process used in the Comprehensive wastewater Master Plan. • Process technology alternatives identification • Pass/Fail Screening • Focus Alternatives Identification • Alternatives development and evaluation — Sizing — Siting — Construction and OW costing — Net present value calculations — Net present value (Ni — Benefit analysis 6% Central San 30% City of San Jose Ash • Them are multiple local end users for ash that are not weather dependent. Biosolids • Local sites available for wet weather land application of biosolids is effectively already at capacity. • Other major agencies in the Bay Area (San Jose) are moving into land application of biosolids, further increasing competition for local sites. • Central San would become 6% of the local market if an alternative requiring land application were selected. New storage and application sites would be required to accommodate biosolids from Central San. ALTERNATIVE ALTERNATIVE 7 Continued Upgrades to Multiple Hearth Furnaces (MHFs) 2 Phased transition from MHFs to Two Fluid Bed Incinerators (FBIs) 3 Replace MHFs with Two FBIs 4 Phased transition from MHFs to Anarchic Digestion and Two FBIs 5 Replace MHFs with Anaerobic Digestion and Two FBIs 6 Replace MHFs with Anaerobic Digestion and Thermal Drying 7 Replace MHFs with a Public -Private -Partnership Facility on the buffer property Based on the pass/fail screening criteria, some processes were eliminated based on results of the end use market assessment, site constraints, technology maturity, and industry phasing out of technology. The seven focus alternatives identified after the pass/fail analyses are shown in the table. July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 16 of 45 4 Page 6 of 32 Altemativle 1: Coondmred Upgrades tD Nk*tW Hearth Furnaces Alternative iconsists of the Phase 1A project plus additional upgrades and replacements of aging process equipment and building systems in the Solids Conditioning Building that are associated with the multiple hearth furnaces to maintain operation through 2052. Phase 1A Components: • Building seismic upgrades Primary New air pollution control equipment Sludge - Landfill, Lystek, other contractor • New centrifuges and cake pumps TWAS Emergency sludge Hoppers Sludge blending tank rehab Landfill Gas Additional Upgrades After Phase 1A r ~� waste Heat Ash system k' Boilers Lime Odor control Blend , v oa9aa I I Equipment ° Multiple Hearth Ash for Natuml Gas Fumarrces (2) Beneficial Reuse Electrical equipment and wiring Polymer system m _b l • Sludge blend tank Turbines Bowers Piping and valves © Emergency sludge hoppers Natural Gas Other Steam Uses LEGEND Cogan New Equipment r Diw—Gas Solids Heat r_ Natural Gas Electricity Er-gly landfill Gas — Liquid Alternative 2• Phased Transition to Replace Multiple Hearth Fasces Phase 1AComponents: with Two Fluidized Bed Incinerators Building seismic upgrades • New air pollution control equipment Alternative 3: Single Project to Replace Multiple FLwnaces �h New centrifuges and cake pumps Two Fluidized Bed Incirlerators��!"�" Yr� Sludge blending tank rehab Additional Upgrades Between Alternatives 2 and 3 ultimately provide the same facility. In Alternative 2, the facility is provided in two phases. The Phase 1Aand Phase 2: first phase includes a new building with one fluidized bed incinerator (FBI) train. The second phase expands the Ash system repairs building and adds the second FBI train. O&M cost estimates assume that during the period with only one FBI, raw sludge will be hauled to landfill or Lystek when the incinerator is out of service. Odor control rehab In Alternative 3, a new building with two FBI trains would be constructed, providing full redundancy. Polymer system replacement • Additional upgrades in the Solids Conditioning Building would be required to keep the existing system operational Electrical equipment and wiring until a new facility is built. The upgrades required depend on the timing of the new facility. In both Alternatives 2 and Emergency sludge hoppers upgrade 3, the existing multiple hearth furnaces and associated equipment would be decommissioned. Blend tanks Phase 2 Components: Binary �, sludge Twns 2 FBI trains each with: LEI [H]� rylandfill, Lysk, other wntractor — nClnemtnr argenvdga Nors warm Neat — Primary and secondary heat exchanger Boi e lantlflll On rsX Waste h — — Waste heat boiler ume � — Air pollution control tt . ..L Blend I cardvip — Granular activated carbon Equipmerf cuidaed Bed Ash n (21 — Wel scrubber m (FBI)— Wet electrostatic scrubber Turbine Blower —Ash system Palocation and reuse of: j — Phase 1Awet scrubber Other Steam Users LEGEND Natural Gras Cogan New Equipment = Digester Gas ® r_ Solids Heat Energy Natural Gas Electrklty 10 Landfill Gas Liquid July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 17 of 45 Page 7 of 32 Alternative 4: Phased Transition to Replace Multiple Hearth Furnaces wilh Anaerobic Digesters and Two FBIs 5: Single Project to Replace Multiple Hearth Furnaces with ]kaesters and We FBIs Alteniatives 4 and 5 ultimately provide the same facility. In Alternative 4, the facility is provided in two phases. The first phase includes one digester and a new building with one Fluidized Bed Incinerator (FBI) train. The second phase adds a second digester and expands the building to add the second FBI train. O&M cost estimates assume that during the period with only one FBI, digested sludge will be hauled to landfill or Lyslek when the incinerator is out of service. In Alternative 5, two digesters and a new building with two FBI trains would be constructed, providing full redundancy. Additional upgrades in the SCB would be required to keep the existing system operational until a new facility is built. The upgrades required depend on the timing of the new facility. In both Alternatives 4 and 5, the existing multiple hearth furnaces and associated equipment would be decommissioned. Primary �© IIr�l1 !� Iantlfill, Lys[ek oMer contractor Slutlge Emergenry a Slutlge Hoppers was to"aaIn Gax Digeslersl3lc x� aafi ror esnefirJal trans. onP w"aruge co-mi—ng r—' FLk-131tNrenWn -. Ri N.ty@IGas An- an1 L g� waste xeat � -• � � � to Digesters OIgM Gas nergY / xllary eoikrs g 17 Phase 1A Components: • Building seismic upgrades • New air pollution control equipment • New centrifuges and cake pumps Sludge blending tank rehab Additional Upgrades Between Phase lAand Phase 2: • Ash system repairs • Odor control rehab • Polymer system replacement • Electrical equipment and wiring • Emergency sludge hoppers upgrade Phase 2 Components: • New dissolved air flotation (D4F) thickener • Two digesters and digester control building • Digester gas combined heat and power • Two FBI trains each with: - Incinerator - Primary and secondary heat exchanger - Cyclone - Waste heal boiler - Air pollutation control - Granular activated carbon - Wet scrubber - Wet electrostatic scrubber - Ash system • FlIelocation and reuse of: - Phase 1Acentrifuges and cake pumps - Phase 1Awet scrubber LEGEND 1 New Equl-ent Digester Gas solids Neat Natural Gas t• Ekceixity Landfill Gas Liquid Alternative 6: Replace Multiple Hearth Furnaces with Anaerobic Phase 1AComponents: Digesters and .Sliudge Drying &Pelletmng Building seismic upgrades Alternative 6 replaces the MHFs with digesters and dryers, producing a dried biosolid pellet instead of ash. New air pollution control equipment Additional upgrades in the SCB would be required to keep the existing system operational until a new facility New centrifuges and cake pumps is built. The upgrades required depend on the timing of the new facility. In Alternative 6, the existing multiple Sludge blending tank rehab hearth furnaces and associated equipment would be decommissioned. Additional Upgrades Between Phase 1Aand Phase 2: • Ash system repairs ® no • Odorcontrolrehab 77T lift'L tanaall, LiawkoMer contractor sl dg Polymer system replacement Electrical equipment and wiring em:rge,�y Slutlge Hoppers cons Emergency sludge hoppers upgrade Ltsao nnaamnle — �Ilalryl"g --� oge.mrslzl iJI ins Phase 2 Components: New Dissolved air flotation thickener „,� sell ale"a aPPneaae" eemawee •Two digesters and digester control DY,p avaJJllllll eo-rnldcenm aril Gas �_ �n waste Heal � xeluylGa i Turb,ne alewer building Digester gas combined heat and power to Digesters A� auxlxryzeolxrs � Two centrifuges and cake pumps 0 Digesters Gs Ercrg/ 1 Sludge dryers, pelletizers cag•" Pellet storage and truck loadout • Sideslream treatment LEGEND • Auxiliary boiler New Equine t_ Digester Gas Relocation and reuse of: solids Heat r_ Natural Gas � Elecbmty - Phase 1Acentrifuges and cake landfill Gas — liquid pumps - Phase lAwet scrubber 12 July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 18 of 45 Page 8 of 32 Alben udw 7: Replace NkdWe Hem d Fulr me s wih a pubic PrKAel PaInership Phase 1AComponents: Altenmtiue 7replaces the MHFs with a facility that would be designed, built and operated by a Public Private Building seismic upgrades Partnership (P3). The selected processes, end product and final disposition for reuse would be the responsibility of the P3. Wastewater generated at the facility would be discharged to a Central San sewer as a permitted industrial New air pollution central equipment discharge. Additional upgrades in the SCB would be required to keep the existing system operational until a new New centrifuges and cake pumps facility is built. The upgrades required depend on the timing of the new facility. The existing multiple hearth furnaces Sludge blending tank rehab and associated equipment would be decommissioned. This option does not include any heat recovery or gas production on site to produce steam. Additional Upgrades Between This alternative assumes that Central San would provide 6 to 9 acres of the buffer property to the P3 and would Phase 1A and Phase 2: construct a pumping station and pipeline to convey thickened sludge from the treatment plant to the P3 site. Ash system repairs The pipeline would need to cross the creek. • Odor control rehab Primary Polymer system replacement Sludge • Electrical equipment and wiring 7WA5 Emergency sludge hoppers upgrade _ I Phase 2 Components: Processes ■ Selected New thickened sludge pumping by P3 New thickened sludge pipe from SCB across Grayson Creek to the buffer property y Blend Thickened Sludge New Blend Tanks Equipment Pumps I LEGEND New Equipment t• Digester Gas Solids Neat Central San o P3 Facility - Natural Gas — Electddty Landfill Gas Liquid DEVELOPMENT OF Development of the seven focused alternatives were performed with input from Central San engineering and operation/maintenance departments and coordination with other capital plant projects, and included: • Application of flows and loads based on previously detennined population projections • Development of mass and energy balances and process unit sizing • Visits to representative facilities (Green Bay, Wl, and St. Paul, MN) • Facility layouts • Site layouts that consider other planned and potential projects (nutrient removal, UV, contaminated soil remediation, new electrical substationl • Incorporation of peer review comments Incinerator Building and Digester at Green Bay, KI 13 14 Fluidized Bed Incinerator at Metropolitan wastewater Plant St. Paul, MN July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 19 of 45 Page 9 of 32 PROJECT CRITERIA All alternatives were configured to meet the following project criteria: • Sized to meet flow and loads for the 2052 projected population of 610,000 (0.75% increase per year) Meet current and projected solids and air emissions regulations Solids loads are based on current treatment processes. Solids loads will remain the same or decrease slightly if nutrient removal is implemented. Maintain at least one end use and a readily available backup for the full solids production Beneficially use inherent nutrient and energy resources Maximize use of landfill gas as long as it is available and beneficial to Central San. (Gas production from the closed landfill is declining over time.) Does not increase GHG emissions from current practice Provide a safe working environment Does not increase odor at the fence line over current practices Transportation and eOCha97 Disposal Cost Model Inputs 1d % GHG Emissions and - GHG Emissions Factors Impacts - End Use — Transportation and po n_ e� • Logistics Requirements LQ Solids and Water Data - Plant Parameters - Resource Recovery Goals � III � Energy Generation/ Consumption — Process/Performance Data Operation, Maintenance, and Net Present Value 16 PROJECTCENTRAL SAN I INTERIM GREEN HOUSE GASES AND CAP AND TRADE All alternatives were developed with the goal of meeting Central San's current operating strategy of maximizing natural gas cogeneration output while staying below the California Air resource Control Board cap and trade threshold. This is beneficial to Central San as the power generated on site currently costs less than purchased power. Alternative Landfill Gas Use Natural Ga. (Net Us. Cap end Trade, E .... dad �Quantity decreases over t Used In MHFs MHF fuel demand increases over time No Continued upgrades to MHFs NG cogen output is reduced with more NG to auxiliary boilers to meet steam demand and ,toy be,,, cap and bade 2&3 Used in FBI. FBI fuel demand decreases over time No Replace hill with Two FBIs Used in auxiliary boilers as available 4&6 Used in FBls FBI fuel demand decreases over yes Replace ldi with Anaerobic Digesters and Two FBI, time Digesters increase heat demand NG to auxiliary boilers increases to ..at steam demand 6 Used in auxiliary boilers Dryerfuel demand increases aver yes Replace hill with Anaerobic Digesters and Thermal Drying time Digesters increase heat demand NG to auxiliary boilers increases to ..at steam demand 7 Used in existing auxiliary boilers No incineration processes consuming NG No Replace MHFs with a Public. NG use in auxiliary boilers increases to meet private Partnership plant steam demand, decreasing NG cogen output In Alternatives 1 and 7, meeting the GHG emission limit is achieved by turning down the existing natural gas turbine and utilizing the more efficient auxiliary boilers to meet the plant's steam demand. In Alternatives 4, 5 and 6, the GHG emission limit cannot be met due to fugitive methane emissions combined with the auxiliary boiler natural gas required to meet the steam demand. Therefore, the O&M costs for Alternatives 4, 5 and 6 include rap and trade fees. Alternative 3 is the only alternative that remains below the GHG emission limit without turn down of the natural cogent turbine while also meeting the plant's steam demand. 76 July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 20 of 45 Page 10 of 32 cost Deuelo My"t For each of the 7 focus alternatives, Class 4 planning level project cost estimates A benefit scoring process was developed to capture the non -cost related impacts were developed using assumptions and markups consistent with the Phase 1A of the project. The categories and criteria are shown in the table. The results from project cost estimates. Operations and maintenance (08M) costs were developed the benefit scoring were used to calculate a benefit cost ratio for each alternative. using Central San's utility, chemical, maintenance contract and hauling prices. CATEGORY CRITERIA CORETHEME Environment GHG emissions and cap and trade flexibility GHG emissions and associated energy use al Environment Environmental impacts al Environment Resource recovery al Social Public impacts (local stakeholders) Technical Reliability/redundancy Technical Safety, operability, and maintainability Technical Flexibility to meet future regulations (including PFAS) Impacts due to pollution, habitat change, or remediation associated with alternative Beneficial resources recovered from solids management process Differentiation between alternatives related to odor, aesthetics, and traffic Operational reliability and resiliency to disaster Staff time and demands required to operate and maintain an alternative. Relative hazard issues Ability for an alternative to meet constraints as population increases and as it may become more challenging to manage nutrient and PFAS loads Technical Constructability The amount of construction constraints associated with an alternative 17 Benefit Category Scoring Criteria (All criteria scored Ito 5, 5 being best.) ALTERNATIVE I ALTERNATIVE 3 Environmental GHG Continued Upgrades to Multiple Hearth, 5 Repam Multiple Heal with Fluid Bed Incinerators 5 ..lesions and I Lowest process GHG Lowest process GHG cap and trade fiexibilily Maximum NG cogen power Maximum NG cogen power Environmental Environmen mI pacts Higher incinerator emissions than Alta 3 and Lower airemissions from FBI than MHF Impacts brine pond habitat Environmental Resour ce • End product is ash: Useable in fertilizer and soil amendments for P End product is ash: Useable in fertilizer and soil amendments for cover recovery/reuse. recovery/reuse. Y • No nitrogen recovery No nitrogen recovery • Potential for use in concoction materials Potential for use in construction materials Social Public Impacts (local stakeholders) Low odor No increase in truck trips Low odor No or low increase in truck trips (chemical deliveries) • No change to current aesthetics •Large newfacilily visible from a distance • Has occasional plume Designed to eliminate visible plumes Technical Reliabilit y/ mdundan More effort and issues in maintaining older equipment and facility New facility, fewest components of the new facility alternatives cy Equipment/system outages during multiple construction projects reduce R/R Redundanttrains Typically shorter maitenance outages for Falls than MH Fs • MHFs require longer annual outage for maintenance than Falls, reducing available redundancy Technical Safely, operability, and Lowest score due to maim of older equipment and 08M difficulty Highest score: FBI simpler to operate than MHF maintainability during multiple construction projects Faster maim. Turnarounds • Dust hazard Technical Flexibility to meet future Possibility for PFAS destruction (Preliminary BACWA testing Possibility for PFAS destruction regulations (including results for ash were non -detect for PFAS) No nutrient recycle to liquid treatment No nutrient recycle to liquid treatment PFAS) MACT 50 requirement for new APC Technical Constmotability • Construction within existing facility Greenfield construction • Highest disruption to existing operations Single phase ofconstruclion • Not suitable for alternative delivery Low distruption to existing operations • Smallest footprint (no new structures) Construction traffic impacts plant • Suitable for alternative delivery • Smallest footprint of alternatives for new facilities • Shortest duration of construction for alternatives for new facilities Average Benefit Score 18 July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 21 of 45 Page 11 of 32 Environmental GHG 4 2 2 emissions and p and trade cowest • Higher process GHG than Alts 1 and 3 Highest process GHG Higher process GHG Flexibility Lowest NO rmgen power Lo NG cogen power Environmental Envronmental t Consumes more of existing site with construction Consumes more of existing site with Central San responsible for permit impacts Impacts partially into capped area construction partially into capped area compliance with operations by others • Impacts brine pond habitat Impacts brine pond habitat Requires sludge pipeline that crosses the creek Environmental Resour c Produces biogas Highest resource recovery: End use is dried Final product and end use unknown recover End product is ash: Useable in fertilizer pellets End use is the responsibility ofthe private partner and soilamendmeme for P Multiple end use opportunities for ovary/reuse. nitrogen and phosphorous reuse • No nitrogen recovery • Potential for use in construction materials" Produces biogas Social Public impacts(localLowotlor stakeholders) Low odor Largest increase in traffic No or low increase in truck trips(chemical deliveries) Multiple large facilities visible Increase in truck trips Multiple large facilities visible from a distance Multiple large facilities, visible from a distance and from the Highway from a distance • Designed to eliminate visible plumes Technical Reliabilit y/ rcaytluntlan IN facility Full redundancy • Level of redundancy and reliability not in District's Redundant trains • Typically shorter maintenance outages for FBIS Most equipment, most potential points of failure control than MHFs Technical Safety, operability, and FBI simplertoopemtethan MHF Lowest score due to most Lowest Central San staffing maintainability Increased requirements compared to Alt 3 with equipment(systems and pellet dust and Central San retains responsibility for overall on addition of digestion fire hazard site safety while not responsible for • Dust and biogas Biogas hazard operations • Increased air pollution control equipment compared Increased air pollution control equipment to Alt 1 compared to Alt 1 Technical Flexibility to meet future regulations Possibility for PFAS destruction Likely no reduction of PFAS Likely no reduction of PFAS (including .Recycle from tlewatering tligestate increases Recycle from dewatering digestale increases Quality and quantity of recycle to plant unknown PFAS) nutrient load to liquid treatment Requires sidestream treatment nutrient load to liquid treatment Requires sidestream treatment Technical Consimctability, • Green field construction Greenfield construction Greenfield construction • Single phase ofconstruction Single phase of construction Least construction of new facilities, least • Low disruption to existing operations Low disruption to existing ops onstructiun traffic within the plant • Suitable for alternative delivery Construction traffic impacts plant Design/build by others • Large footprint Sui Ie for alternative delivery Requires 6-9 acres • Construction traffic impacts plant Lar tfoolprint Ils The leading alternative for the Phase 2 project, a new fluidized bed incinerator facility, had the highest Benefit/Cost Patio, with the highest benefit score and the second lowest net presentvalue (NPV) cost. On -going phasing analyses will look at the optimal timing for Phase 2. Project costs associated with upgrading existing facilities could upgrades to Multiple Hearth Furnaces Alternative 3-Replace MHFs 192 405 94 2042 313 373 365 738 4.1 5.6 with two FBIs Alternative 5-Replace 192 535 94 2042 321 482 466 948 3.4 3.6 MHFs with Anerobic Digesters and Thermal Drying Alternative 6-Replace fill 192 482 94 2042 289 462 390 852 3.0 3.5 with Anerobic Digester and Two FBIs tJ," iy�gWiace MHFs 192 50 48 2042 20 211 710 921 2.3 2.4 �tl99 panWb txc�— wi me $-2s T ee;xdx1 vmgerr<a�tem�aab-tp�b*tp�lssa —ity14=TramuestrbewdAx1xhr—n„,a.va Rged m Qffi4mKmlrheltlNe—.heaea&aagra9'�an9afuraC�d�maes3%b <R'aL�aIOIMpr4�b311�161n1r911ntl urAl rervracifly'swur�a�tTswaki.Ftl'el�'rr®Its B*mmae CBasM ogxxk'J­Wd0'htal 5 TrerirHtO�eian9vJcatnnetlof tie INamingpaiodbnV rune pn�IlafweHlRalareyary Alternative A3 NE _—_— Altemative%$ EN -_-- ■ GHG emlalow antl cap antl batle gerlblllty ■ %iliblityl—ndancy Altemative Rf 01 —_ ■ Environmental impact ■ —ty, opnebility, and.-ibilay Alternative RS -_■ ■ %4Ouf—01'eN nenibilyto meet Ntun regulations lindudim PFAS) Alternative R] of ,.- ■ Publl Impact (local stfl-idera)NE ConaWcnbllMy 0 2 3 4 5 Average Benefit Score (Higher is Better) July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 22 of 45 10 Page 12 of 32 MOVING FORWARD: DIGESTION AND/OR INCINERATION lrrmpactm Wuhiets The digestion process releases nutrients from the sludge that would be recycled back to and impact the plant. Therefore sidestream treatment (biological nutrient removal of the centrate) is included. This adds to footprint, project and O&M costs. Energy and Olimim g costs The benefit of generating biogas and utilizing the biogas to produce electricity does not offset the added O&M of the digesters, sidestream treatment combined with FBIs or thermal dryers. Additionally, the digester alternatives cannot meet the plant steam demand without surpassing the GHG rap and trade threshold due to the natural gas demand of the auxiliary boilers. As noted previously, only the FBI alternatives stay below the cap and trade limit and meet the plant's steam demand. Ed Use Based on the end use market assessment, digestion was paired with incineration or drying for comparison with incineration. Ash and dried pellets have more potential beneficial uses and incineration provides a higher WAS reduction potential than digestion alone. Footprint With digestion ahead of incineration, the incinerator size is smaller than for incineration alone. However, the combined footprint of digesters with incineration is larger. The footprint for digesters with drying is the largest of the altematives considered. R—mir rerrdatim These and other factors led to the relative costs and benefit scoring presented. Based on these analyses and the results of multiple workshops with Central San staff, the allerrretiues wilh iwilaratim only (AMernatl a 1, 2 ad 3) ai, reoornmended for the rind phases of the a firller refinement and ph 0 n MOVING FORWARD: FURTHER PROCESS AND PROJECT REFINOVENT Aftemartue energy eraluallk : All alternatives were developed based on a single energy strategy for the plant. Alternative strategies will be developed. For example, alternative power generation scenarios will be developed based on considerations to continue using steam to drive the aeration blowers or to use the steam to make electricity to power the electric blowers. An evaluation of the existing natural gas cogeneration system is planned to analyze remaining useful life and replacement strategies. Sensitirily analyses There have been changes in power, fuel, chemical and construction costs over the last few years. Multiple price scenarios will be run to determine if any result in a change in the relative cost rankings of the highest rated alternatives. SftbV For consistency, all alternatives were developed based on the same assumed location. Alternative locations and configurations will be considered for the highest rated allematives. Plefnements of the new facility alternative will include layout options that could reduce building size and cost. Cmtirred coadiiation wrlh atimer prajeets This evaluation has been coordinated with the ongoing steam projects, the 11V project, future nutrient removal and the planned Substation 90. Additional detail regarding the Phase 2 project needs to be developed for electrical integration and Substation 90 sizing. To view the interior layout of the Alternative 3 facility in 3D, use QR code or web link below bgpa://aDi2.enscaoe3d.conJv3/view/link/5b920916-124e-4076- 9123-bee07b2294bb/039Bd0ca-72e1-4b7c-al00-6b0525dbcda 22 July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 23 of 45 11 Page 13 of 32 PHASING EVAUTATKM Project timing and phasing (building the facility in one or more construction projects) is currently being evaluated. The evaluation is taking into account: • Remaining useful life of existing facilities after Phase 1Ais complete • Coordination with other potentially concurrent construction projects • Impacts to plant operations Schedule and Cost Current estina6e in $400.500 icrRase2 Solids Phase 1A FConstruction • Future upgrades to the Solids Conditioning Building are reduced by building a new facility. The amount of reduction depends on the timing for the new facility. • NPV based on project timing Cash flow The current analysis considers Phase 2 completion between 2032 and 2042. Solids Phase DesigN—osWction Regulatory or higher Operational in 2042 investments to maintain existing system may trigger initiating Phase 2 sooner Facity Upgrades Behiflem Phase lAand Phase 2 Air pollution control equipment Regulatory Yes 36 Electrical upgrades and replacements Aging infrastructure Yas 37 Ash, odor control, and polymer system repairs Aging infrastructure No 11 Valve and piping replacements Aging infrastructure No 5 Solids loudout upgrades Aging infrastructure Yes 5 The proposed Phase 2 project could be the largest single project for the District since the 1970's Water Faclamation Pland 5A project. Fecognizing the importance and impact of this project over the next 30 to 50 years, Central San selected a group of industry experts to provide a peer review of the findings thus far. Expects from the following firms participated in the peer review process: AECOM, Carollo Engineers, GHD, HDR and Jacobs. W It 0 24 Maximizing value of existing assets would trigger initiating Phase 2later The peer review process provided valuable insight and input that: • Helped refine facility and site layouts • Identified additional air pollution control alternatives for consideration • Guided additional considerations in the benefits scoring • Verified costing assumptions fbndering of Proposed Fluidized Bed Incinerator Facility July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 24 of 45 12 Page 14 of 32 ` 114 0111 The altematives were developed with new facilities located north of the SCB and south of the capped contaminated soil area. Peasons for using this site include: • Minimal disruption of contaminated soil • Maintains areas reserved for nutrient removal, tN and Substation 90 projects., The UV project construction is projected to begin in the next few years. • Proximity to existing utility corridors and the ability to connect to them through the Contaminated soil Area SCB basement • Proximity to and ability to reuse the 1 r existing emergency sludge storage and/-- , truck loadout system / .>>�•, > >>>-> Impacts of this location that need further J ` > > > > > - Wwre uv consideration include: >>>�>i/`� > > > > > • The faality extends into the brine pond area and the south corner of Basin A`/ - South This will require filling in the brine \ r l> pond and part of Basin A This may require habitat restoration or relocation. 411 Proposed Fluidized Bed / mentor Feaiity • The facility encroaches into the staging P �� area established for contractors. The level of impact will depend on the timing for Phase 2 construction. Siting and layout alternatives will be developed during the refinement stage of the work. ' 25 LONG-TERM SOLIDS STRATEGY .►tom. .. The interim project summary and strategy presented for review are based on selecting the most appropriate technology to replace the MHFs and optimizing the timing of that replacement. Based on the analyses of technologies with proven experience at the scale of Central San's plant, fluidized bed incineration is the recommended replacement technology. The recommended implementation of a long -tens solids strategy consists of three parts: Pat 4 The Phal 7ARoject The Solids Handling Facilities Improvement Project Phase 1Ais being implemented to meet immediate and near -tens needs and it provides the benefit of extending the life of the MHFs. Additional modifications and system replacements would be needed to extend the life of the full MHF system. Not Z Fa3ty Additional upgrades to some systems in the SCB extends the useful life of the SCB, increases the value of the lAproject and provides Flexibility to optimize the timing for Phase 2. The amount and extent of additional upgrades depends on the selected Phase 2 timing. These upgrades would be implemented in multiple projects. Pat 3: The Phase 2 Project The costs, risks, and operational impact of continuing to modify the SCB will be developed in more detail to determine the optimum timing for replacement with a new facility. The analyses presented are based on bringing a new facility online in 2042; 15 years after the completion of the 1Aimprovements. Impacts of constructing Phase 2 construction earlier depend on the timing and include: • Avoid regulatory triggers that may require additional emissions controls for MHFs • Reduce cost of modifying existing SCB systems • Peduce risk of failure of aged infrastructure • Construction and expenditure for the new facility would be concurrent with other major projects Leverage asset management data to build the case for when to rehabilitate and when to replace 26 July 10, 2023 ECIPS Regular Committee Meeting Agenda Packet - Page 25 of 45 13 Page 15 of 32 NIP 77{i, r I CENTRAL CONTRA COSTA G SANITARY DISTRICT j� Prepared for Central San by Brown AND Caldwell ' July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 26 of 45 14 Page 16 of 32 July 10, 2023 Solids Handling Facilities Improvements Phase 2, DP 100030 Interim Project Summary Nitin Goel Optimization Division Manager July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 27 of 45 1 Page 17 of 32 Background Existing Facilities Central San's existing multiple hearth furnaces (MHFs) have reliably converted solids from wastewater treatment to ash for more than 45 years. Resource recovery through steam generation from waste heat and beneficial ash reuse (including phosphorous recovery) are consistent with Central San's vision to be an innovative industry Leader in environmental stewardship and sustainability, while delivering exceptional service at responsible rates. July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 28 of 45 2 Page 18 of 32 Path Forward for Solids Handling Part 1: The Phase 1A Project The Solids Handling Facilities Improvements Project, Phase 1A (Phase 1A) is being implemented to meet immediate and near -term needs and it provides the benefits of extending the life of the MHFs. Additional modifications and system replacements would be needed to extend the life of the full MHF system. Part 2: Facility Upgrades Additional upgrades to some systems in the Solids Conditioning Building (SCB) extends the useful life of the SCB, increases the value of the Phase 1A project and provides flexibility to optimize the timing for Solids Handling Facilities Improvements Project, Phase 2 (Phase 2). The amount and extent of additional upgrades depends on the selected Phase 2 timing. These upgrades would be implemented in multiple projects. Part 3: The Phase 2 Project The costs, risks, and operational impact of continuing to modify the SCB will be developed in more detail to determine the optimum timing for replacement with a new facility. The analyses presented are based on bringing a new facility online in 2042; 15 years after the completion of the Phase 1A improvements. Impacts of constructing Phase 2 construction earlier depend on the timing and include: • Avoid regulatory triggers that may require additional emissions controls for MHFs • Reduce cost of modifying existing SCB systems • Reduce risk of failure of aged infrastructure • Construction and expenditure for the new facility would be concurrent with other major projects Phase 1A Project Benefits Improvements needed to keep incineration reliable for 15+ years New air pollution control equipment to meet air regulations today and in the future Reliability, Safety, and Sustainability Sludge Blending Tank (storage before dewatering): cover needs replacement due to significant corrosion Centrifuges and Cake Pumps: equipment well beyond useful life and not reliable. New dewatering equipment will have improved energy efficiency. Seismic improvements for safety and sustainability of the building housing incinerators, dewatering equipment, and air pollution control. Bid results for construction are July 13, 2023. 11 July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 29 of 45 3 Page 19 of 32 Facility Upgrades Between Phase 1A and 2 Additional facility upgrades would be implemented between the completion of Phase 1A and start of Phase 2. The amount and extent of additional upgrades depends on the Phase 2 timing. It is expected that these upgrades would be implemented in multiple projects, with some upgrades being reusable in Phase 2. A Phase 2 Project Overview Phase 2 is planning effort to develop Central San's long-term solids management strategy over the next 30 years. Two overarching goals: Identify the future solids handling process to ultimately replace MHFs. Develop a phasing plan to maximize the value of existing assets while starting Phase 2 early enough to ensure a smooth transition. Review key findings from the draft Interim Project Summary in advance of Phase 1A bid results. WTMM PMECT SUMMARY Solids Handling Improvement Phase 2 f DRAFT e _ ti �urte 20�3 Ll bxna Apectlio0a�o CENTRAL AN ■ July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 30 of 45 4 Page 20 of 32 Phase 2 Project Approach w trye.step Wa ess was aevolapea to peagress tbroogjh the phew 2 o,oluaaWn. rlpaatW anign uaaag --1,1- d hosed M ravaed popel,u- eed IaDdeg proieeli s A merpet es6essmpnl. leeeplrg -:able benenclal uses In rmntl, was mntlucletl [o Itlenaty the potentla[ use; users and casts F. the 11-1 solids produce}rom thevariousmNdstrea mlaQernamres. C.wwi and 08M costs and b nefl scores were cl—1 p�d to comome dternotires. The otlemellres wllh the highest Gene &� C:ost scores are being f�nher evaluated for phasing. The long term sua<egy will recommend the path for the eventual replacement a the mulllple neanh lwnaces. Review key findings from the JtQ Updawdinng-term ; draft Interim 8 strategy Project Summary Furtherre5nement t%1 •FAarted[MM ofbesfsearing in advance of . Identified end uses the unh�cvae of ahefnalives altemal" and cdnsideraw ; Phase 1A b i d - Flow and for sludge after • Evaluated Seven of when to start results. Ipud updates solids handling g ahernatrves in Phase 2 Design - Regulatory Treatment more delall and Construction evaluation (I.e. ctiamly ashj • Iacorpormed peer • Rewewed review culnrrlents regional costs and , Advanced best 9 markel trends wodng aheraYeves To pha5i ng evaluation Alternatives Evaluation July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 31 of 45 5 Page 21 of 32 do%* Alternatives Evaluation Process technology alternatives identification Pass/Fail Screening Focus Alternatives Identification Alternatives development and evaluation Sizing Siting Costing Benefit analysis 4%..� Established Universe of Options BIOSOLIDS STABILIZATION TECHNOLOGIESInnovative Embryonic Thermal Conventional Conventional Windrow Direc[Thermal Alkaline Fluidized H drol is Steam y ys (Steam) (Mesophilic) Aerobic D tying Stabilization Bed Reactor Anaerobic igestion Digestion (MAD) Enclosed/ Incinerator Biological (Acid) In-vesselF Indirect EnVessel Hydrolysis Auto- Thermal Pasteurization M ultiple Phased Thermophilic Aerated Static Drying(RDP) Hearth Aerobic Anaerobic Pile Furnace P asteurization Chemical/Thermal re-p Digestion Digestion (ATAD ) Solar Drying Schwing Incineration Hydrolysis (TPAD) Bioset Aerobic/Anoxic Membrane Covered Pile Vertical Tray Dryer/Furnace Aerobic Intermediate Di Thermophilic Digestion Dryers Lystek Thermophilic Thermal Anaerobic Super-Critical Su Critical Pretreatment Hydrolysis Digestion Vermi- Wet Oxidation Composting Flash Dryer VitAg/Anuvia Fertilizer Pulsed Electric Pyrolysis Hydrolysis Multi -Stage Hybrid Fluidized Digestion Compost Bed Drying BCR Clean-B Solid Stream Systems Gasification Thermal Hydrolysis MAD +Post Hydrothermal Aerobic Liquefaction Digestion Thermal Hydrolysis Recuperative (No Steam) Thickening High Solids Digestion July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 32 of 45 6 Page 22 of 32 Pass/Fail Criteria for Initial Screening Screening from the Universe of Options Applying Pass/Fail Criteria Eliminated solar drying: market assessment & site constraints Eliminated gasification: technology maturity/reliability Eliminated several thermal hydrolysis process (THP) technologies/combinations: technology maturity Reduced advanced digestion alternatives for several scenarios Eliminated new MHFs as technology is being phased out by the industry Phase 1A is included in all alternatives due to ageing infrastructure and regulatory drivers, as well as time required to implement a Phase 2 project (5-7 years from design to commissioning). *except for Public/Private Partnership Alternative 'TIM P ts.., ENi July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 33 of 45 Page 23 of 32 Alternative 1: Continued Upgrades to Multiple Hearth Furnaces Primary ., Sludge Landfill, LystaK adner eanvactor TWAS Emergency Sludge Hoppers Landfill Gas Waste Heat LEGEND Lime 4 80l lers � New Equipment � D3gester Gas ` CentAfuges Solids Heat Blend Mulllple Ash for 211111111111 Natural Gas Electricity Equipment tu Naral Gas Fuma2nces { i ! Beneficial Reuse LandTiEl Gas Li4uld A Cogen Energy Turbines Bowers Other Steam Uses Ash Steam from MHF/Cogen Yes, by turning down NG Cogen Alternatives 2 & 3: Phased Transition to Replace Multiple Hearth Furnaces with Two Fluidized Bed Incinerators (FBI) Primary Sludge TWS Lendlil, Lysiek,alaer [ lrmtbr Sl Hcr+➢a E rage uapr % WseW Hem �Odw Lardall Gas LEGEND New Equipment nonniii D3gester Gas ume ` Solids Ht }} Natural Gas Eleceatricity HI and I Ash cs..n;wya T TiH LandGas Uquld Equipment Q FlUldixed ae0 "H owmi Gas IrsrIM trail n �} A %rains a"" S ,4-1rery 9elrers fq omen sL�m user,: Meet Existing Steam System End Sream Cogen Energy _ Energy Recovery: Demands and Trade Ash Steam from FBI/Cogen Yes July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 34 of 45 8 Page 24 of 32 Phased Transition or Single Project to Replace Multiple Hearth Furnaces with Anaerobic Digesters and Two FBIs . ,[. Y T V 11" lanEhll. -VLO, elver ro lffl&er rmary 4ni •.I r. •;�m� Sludse r•,i �,r rn Emergeney WR5 srra9e Happa+s LEGEND New Equipment Digester Gas Landfill Gas solids Heat allim Ri ,een+er aer,enaal aeuse Natural Gas Electricity —� MHOAMMOtlrC lJl7 _ _ Landflil Gas Uquld �u � LLLJJJ . Co-TlPiicFkvnlrrp FIui1lyed6M Indneremn N.11 C;-% fir} irneflll6as YIdEI�� Meet Existing Steam System End Use Product- Energy Recovery: Demands without entering Cap and Trade 17 NDfM &0nM [p �iyapers W �� E^er9Y �ro� 90YErt {� Steam from FBI/Digester Ash No Gas Cogen Replace Multiple Hearth Furnaces with Anaerobic Digesters and Sludge Drying & Pelletizing f�rimary IL 'u yc'. .. �� LAndeM, LYS>»I4 gNpr COnlrnt[pr iwoge Sln..st Emeryarcy W ge Hop i. .,,tniplfi{f 51 pers WAS1'� LEGEND New Equipment Digester Gas l Drying Solids Heat �� r pneerob[c in ree" ru J11111111111111111 Natural Gas Electricity !J l� �sd[elerwauprMarlw, iandrHGas — uquld �AiF nenLrlluge j� �!"8� [;pTrll nlny LariM 6ea Wesle Heet - _-- — ttuolne Blower Nalypl Gar to Pigenerc 11 AW O ia v PIgMlers Fas E—gy Ash Digester Gas Cogen No July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 35 of 45 9 Page 25 of 32 Alternative 7: Replace Multiple Hearth Furnaces with a Public Private Partnership (P3) Primary Slutlgn I I I nVaS I I I I � LEGEND —� I Processes r-7 New Equfpment Digester Gas I !xy P3 Solids Heat Natural Gas Elect.iCity I LandTiEl Gas Li4ufd Blend Thickened Sludps I Equipment pL,,,Ps I I I I I I I Central San I P3 Facility End Use Product: Energy Recovery: Meet Existing Steam System - NA NA Yes, by turning down NG Cogen Alternative 7: Public Private Partnership - Current Major Assumptions Location: Kiewit Property (land lease) 4�9 Purveyor: Lystek, Anaergia, or Other Process: To be determined by Purveyor Logistics: Central San delivers (pumps) thickened sludge to P3 site P3 provides all further processing and end use disposal P3 designs, builds, finances, operates and maintains facility and vehicle access P3 provides and pays for all needed utilities including sewer discharge to Central San No heat/energy recovery for Central San plant July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 36 of 45 10 Page 26 of 32 i Analysis n Benefit Cost Ratio = Benefit Score 30-year net present value (NPV)' x:. Higher Benefit Cost Ratio is better Higher Benefit Score is better � N, Lower NPV is better -., ,- r- Benefit Criteria Category Environmental Criteria Greenhouse Gas (GHG) Emissions and CoreTheme GHG emissions and associated energy use, air pollution, etc. Cap and Trade Flexibility Environmental Environmental Impacts California Impacts due to pollution, habitat change, or remediation associated Environmental Quality Act (CEQA) with alternative. Environmental Resource Recovery Beneficial resources recovered from solids management process. Social Public Impacts (Local Stakeholders) Differentiation between alternatives related to odor, aesthetics, and traffic. Technical Reliability/Redundancy Operational reliability and resiliency to disaster. Technical Safety, Operability, and Maintainability Staff time and demands required to operate and maintain an alternative. Relative hazard issues. Technical Flexibility to meet future regulations Ability for an alternative to meet constraints as population increases (including Per- and polyfluoroalkyl and it becomes more challenging to manage nutrient and PFAS substances PFAS loads. Technical Constructability The amount of construction constraints associated with an alternative. zz July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 37 of 45 11 Page 27 of 32 Relative Benefit Scores (Straight Average, no Weighting) Alternative #3 F81s Alternative #5 Digestion+FBls Alternative #6 Digestion +D rye rs Alternative 41 Status Quo Alternative #7 P3 0 1 2 3 4 5 Average Benefit Score [Higher is Better] Benefit/Cost Results ■GHG Emissions and Cap and Trade Flexibility ■ Environmental Impacts CEQA ❑ Resource Recovery ■Public Impacts (Local Stakeholders) ■ Reliability/Redundancy ■Safety, Operability, and Maintainability []Flexibility to meet future regulations (including PFAS) ❑ Constructabi lity Altamative 7- Continued upgrades 192 148 12 285 377 ssz 3.1 4.7 to Multiple Hearth Furnaces Altemativo 3 - Replace MHFs with 192 405 94 2042 313 373 365 738 4.1 5.6 two Fels Aiterrntive S - Replace MHFs with Anerobic Digesters and 192 535 94 2042 321 482 466 948 3.4 3.6 Thermal Drying Alternative 6 - Replace MHFs with 192 482 94 2042 289 462 390 852 3.0 3.5 Anerobic Digester and Two F519 Alternative 7 -Replace MHFs with a 192 50 48 2042 20 211 710 921 2.3 2.4 Public -Private Partnership 1bNl eosv me n 1�1� anNe's ]. finese to inuioa toss ere rased on lne<rr�eeh Coss tcorsnccvm esummed 1t30t35M iM e�atu�scurarrmyelma Qmstmmne cq%to �t5%. Bias media Julrt; 3613.r�tebk wa Le uPaStea eRer Gas me rueeiteu. P W. [Oftf One �OSSQ On CLASS 4 CenSlil[tVSI ro5t lavlN3¢S iRe aPeaea M[mOry tetye Im a CLASS 4 efYMle a -DR 7C.5M 4. dJrticipeted tocui6es upgmaes m 30 rest Wemire DS*'ca mai newtulxr's epme[imel iFiswmk o'm Ne pinrvwg Ota>se. Esanetea ate Clms 5 win on �ecazd xumrcY range d.5996 m+gVtL i ITe S�vne MSememing rNue ma,eeM o<tlSe ylemkg tcnua CmN en lit getter Wuseful be remainims. July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 38 of 45 12 Page 28 of 32 Peer Review Process The proposed Phase 2 project could be the largest single project for Central San since the 1970's Water Reclamation Plant 5A project. Recognizing the importance and impact of this project over the next 30 to 50 years, Central San selected a group of industry experts to provide a peer review of the findings thus far. Experts from the following firms participated in the peer review process: AECOM, Carollo Engineers, GHD, HDR, and Jacobs. Subject matter experts were also engaged during the project to provide specific input on steam system integration and fluidized bed incineration building layout. July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 39 of 45 13 Page 29 of 32 Moving Forward Digestion vs. Incineration End -use Ash from FBI would require less trucks and cost for beneficial reuse than anaerobically digested sludge pellets. Additionally, initial results from sampling show ash has non -detectable levels of PFAS. Nutrient return With incineration, nitrogen goes into the atmosphere and most of the phosphorous goes to ash for beneficial reuse. The digestion process releases significant amounts of nutrients into liquid form. Central San anticipates sidestream treatment would be needed to remove nutrients, which is an additional biological process which adds cost. Moving Forward Digestion vs. Incineration Energy and Operating Costs The benefit of generating biogas and utilizing the biogas to produce electricity does not offset the added operations and maintenance cost of the digesters, sidestream treatment combined with FBIs or thermal dryers. Additionally, the digester alternatives cannot meet the plant steam demand without surpassing the GHG cap and trade threshold due to the natural gas demand of the auxiliary boilers. As noted previously, only the FBI alternatives stay below the cap and trade limit and meet the plant's steam demand. Footprint With digestion ahead of incineration, the incinerator size is smaller than for incineration alone. However, the combined footprint of digesters with incineration is Larger. The footprint for digesters with drying is the largest of the alternatives considered. July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 40 of 45 14 Page 30 of 32 Fluidized Bed Incineration is Highest Scoring Future Solids Handling Technology CeMeninMe650-I Wee NEW Near Term Strategy The Phase 1A is being implemented to meet immediate and near -term needs and it provides the benefit of extending the life of the MHFs. Additional modifications and system replacements would be needed to extend the life of the full MHF system. F Propwed FYiidimd 9c I�rilclemr Faeliq -- 1 .r for", �. T T July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 41 of 45 15 Page 31 of 32 Facility Upgrades Additional upgrades to some systems in the SCB extends the useful life of the SCB, increases the value of the Phase 1A project and provides flexibility to optimize the timing for Phase 2. The amount and extent of the additional upgrades depends on the selected Phase 2 timing. These upgrades would be implemented in multiple projects. The costs, risks, and operational impact of continuing to modify the SCB will be developed in more detail to determine the optimum timing for replacement with a new facility. Long Term Strategy The analyses presented are based on bringing a new facility online in 2042; 15 years after the completion of the Phase 1A improvements. Impacts of constructing Phase 2 construction earlier depend on the timing and include: Avoid regulatory triggers that may L require additional emissions controls for MHFs Reduce cost of modifying existing SCB systems Reduce risk of failure of aged infrastructure Construction and expenditure for the new facility would be concurrent with other major projects July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 42 of 45 16 Page 32 of 32 Strategy to Prepare for a Smooth Transition from Existing to Future Solids Handling Facility Facility upgrades between the completion of Phase 1A and start of Phase 2. The amount and extent of additional upgrades depends on the Phase 2 timing. These upgrades would be implemented in multiple projects, with some upgrades being reusable in Phase 2. Maximizing value of exisling assets would Solids Phase 1A trigger initlating Construction Phase 2 later 2023 2025 2027 1. 2029 2031 20M 2035 2037 2039 2041 2043 Solids Phase 2 w Nsign(Construction Phase 1A Project is Regulatnry or higher t]pera11onalln2642 imperative to reliable operation of MHFs due to aging infrastructure, regulatory, and safety drivers. investments to maintain existing system may trigger initialing Phase 2 sooner July 10, 2023 EOPS Regular Committee Meeting Agenda Packet - Page 43 of 45 17