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HomeMy WebLinkAbout01. Tour of the Membrane Aerated Biofilm Reactor Pilot, Aeration Basins Diffuser Replacement, Phase 1 and Solids Handling Facility Improvements, Phase 1A ProjectsPage 1 of 12 Item 1. LICENTRAL SAN June 18, 2024 FROM: MICHAEL CUNNINGHAM, ASSOCIATE ENGINEER REVIEWED BY: NITIN GOEL, OPERATIONS OPTIMIZATION DIVISION MANAGER EDGAR LOPEZ, CAPITAL PROJECTS DIVISION MANAGER GREG NORBY, DEPUTY GM - ENGINEERING & OPERATIONS ROGER S. BAILEY, GENERAL MANAGER SUBJECT: TOUR OF THE MEMBRANE AERATED BIOFILM REACTOR PILOT, AERATION BASINS DIFFUSER REPLACEMENT, PHASE 1 AND SOLIDS HANDLING FACILITY IMPROVEMENTS, PHASE 1A PROJECTS NOTE: NO DECISIONS ORA CTIONS WILL BE MADE OR TAKEN BY THE BOARD OF DIRECTORS DURING THE TOUR. ANY MEMBER OF THE PUBLIC THATAPPEARS WILL BEACCOMMODATED; PERSONAL SAFETYEQUIPMENT MUST BE WORN DURING THE TOUR. Staff will provide a presentation (attached) followed by a tour of the Membrane Aerated Biofilm Reactor Pilot, Aeration Basins Diffuser Replacement, Phase 1 and Solids Handling Facility Improvements, Phase 1 A projects. Strategic Plan Tie -In GOAL TWO: Environmental Stewardship Strategy 4 - Identify and advance sustainability initiatives, including reducing energy usage and emissions GOAL SIX., Infrastructure Reliability Strategy 2 - Execute long-term capital renewal and replacement program GOAL SEVEN: Innovation and Agility Strategy 2 - Implement organization -wide optimization ATTACHMENTS: 1. Presentation June 18, 2024 Special Board Meeting Agenda Packet - Page 3 of 14 Page 2 of 12 Outline Existing secondary treatment process overview Membrane Aerated Biofilm Reactor (MABR) technology overview Pilot project equipment Initial pilot results Tour of MABR Pilot, Aeration Basins Diffuser Replacement, Phase 1 and Solids Handling Facility Improvements, Phase 1A projects June 18, 2024 Special Board Meeting Agenda Packet - Page 4 of 14 Page 3 of 12 Existing Treatment Plant Constructed for Carbon Removal Process has performed well for many years thanks to diligent operation and maintenance, plus capital projects to extend useful life of existing equipment. 26 years of National Pollutant Discharge Elimination System Compliance, 1 of 13 agencies nationwide. Capital Improvement Projects in progress to address aging infrastructure challenges and extend the remaining useful life of high value assets with concrete repairs and seismic upgrades. Existing process removes 18 - 27% of influent total inorganic nitrogen (TIN) through solids being incinerated in the Multiple Hearth Furnaces. This converts nitrogen in the solids into nitrogen gas. Central San's existing recycled water program helps customers beneficially reuse nitrogen in landscape irrigation. However, biological process cannot further remove TIN without expansion to accommodate high mixed liquor concentrations or process intensification with a new technology. Central San Current Wastewater Treatment Plant Secondary Process Flow Configuration Wastewater from Ultraviolet coo..., Collection Disinfection ° System Primary Headworks Clarifiers Anaerobic Aeration * Secondary Then Recycled Water Selector Tanks or Cutfall to Suisun ( (4) Clarifiers Bay I4) (8) Scrubbed Flue Gas to • Atmosphere Return Activated Sludge Ash to Beneficial Reuse Waste Activated Return Flows to Plant Dewatering Sludge and Incineration *Anaerobic Selector is mixed but with no aeration or dissolved oxygen. June 18, 2024 Special Board Meeting Agenda Packet - Page 5 of 14 2 Capital Projects in Construction to Improve Secondary Treatment Process Electric Blower Improvements, District Project (DP) 100015 Full redundancy for air supply to tanks with new electric blowers Page 4 of 12 Aeration Basin Diffuser Replacement and Seismic Upgrades, DP 100019 Replace aged diffusers with state of art membrane diffusers for improved efficiency and performance - Rehabilitate south selector to allow for north selector to be taken offline for rehabilitation and allow for new treatment configuration Expansion for TIN Reduction with a Conventional Treatment Process If nutrient removal were required for a recycled R �nW•n�i G0m�0Yk•Mvim vwnl e Th[�ieu water project (i.e. Water Exchange) or regulatory requirement, Modified Ludzack Ettinger (MLE) is the placeholder process Benefits Established and proven treatment process. Challenges ' Significant construction effort for contaminated soil relocation/removal and new secondary clarifiers and aeration tanks. Completing maintenance in dry weather season (May - October) would require adding new staff or seasonal contractors. *MLE process increase the solids retention time to allow bacteria who use nitrogen as a food source mom grow. This requires more aeration tank volume and clarifiers to treat the same capacity. June 18, 2024 Special Board Meeting Agenda Packet - Page 6 of 14 3 Page 5 of 12 Central San Potential Conventional Future Process Configuration with MLE for TIN Reduction Wastewater ° o ° o ° o ° o ° o Ultraviolet from ° o ° o 0 Collection ° ° , o o Disinfection System Primary Anaerobic Then Recycled Water Headworks Clarifiers Aeration Secondary or Outfall to Suisun (4) Anoxic Tanks Clarifiers Bay Scrubbed Flue Gas to 1 Selector* (44$) (8 10) Atmosphere Return Activated Sludge Ash to Beneficial Reuse Waste Activated Return Flows to Plant Dewatering Sludge *Anaerobic Selector is mixed but with no aeration or dissolved and Incineration oxygen. Anoxic selector would be mixed with no aeration but would kahlow, have nitrate available that contains oxygen. Process Intensification Technologies Help Achieve More Treatment in the Same Tankage Conventional (i.e., MLE) Intensification Conventional + Intensification Intensification of existing infrastructure is preferred. However, being able to reliably meet treatment objectives will depend on regulatory limits and technology performance. June 18, 2024 Special Board Meeting Agenda Packet - Page 7 of 14 4 Page 6 of 12 MABR Process Intensification Technology Overview Cassettes consisting of many membranes are placed into an unaerated zone of a tank or channel. Air flows through the membrane allowing a biofilm of bacteria to grow on the surface. This biofilm bacteria population attached to the cassettes, unlike Central San's current bacteria population, use nitrogen as food. Therefore, they could add nutrient removal capacity without adding clarifiers or aeration tanks. a Mbk/ anoair/ nn°ak/ nitrifying denitrifying denitrifying gi°film g°]k lumen wall f�quid 0, NH NO p— COD N, Distanceh .—h—s°0— Process Intensification Locations Identified for Pilot Testing MABR Cassete Potential Locations Wastewater ° o o o o o o, Ultraviolet from o° o°° o Disinfection Collection ° o ° ° o ° ° System Primary Anaerobic Aeration Then Recycled Water Headworks Clarifiers Selector Tanks Secondary or Outfall to Suisun (4) (4) Clarifiers Bay (8) Scrubbed Flue Gas to 1 Atmosphere Return Activated Sludge Waste Activated Ash to Beneficial Reuse Sludge Return Flows to Plant Dewatering and Incineration A June 18, 2024 Special Board Meeting Agenda Packet - Page 8 of 14 5 Page 7 of 12 Consultant Project Team Mike Falk, P.E., Ph.D HDR, Inc. (Lead Consultant) • Paul Pitt, P.E., Ph.D, BCEE Hazen and Sawyer (Peer 1?t4 Review) QVEOIIA Equipment Vendors Glen Daigger, P.E., Ph.D, BCEE NAE One Water Solutions, LLC (Peer lkv�t� Review) .r. Ell ' - F� y 1. SD CENTRAL SAN ��. CENTRAL CONTRA COSTA SANITARY DISTRICT - June 18, 2024 Special Board Meeting Agenda Packet - Page 9 of 14 6 MABR Pilot Influent Water Locations Wastewater from — Collection System Headworks Scrubbed Flue Gas to Atmosphere Page 8 of 12 __t_tReturn Activated Sludge JWaste Activated Dewatering Sludge MABR Pilot Feed Locations and Incineration Q Phase 1 - Secondary Clarifier Influent © Phase 2 - Anaerobic Selector 0 Phase 3 - Aeration Tank MABR Pilot Water System Feed Pump from Anaerobic Selector Feed Pump from Secondary Clarifier In-proc Ammonia/ Nitrate Probes Shipping Container with MABR 02 Content Monitor """"""' MABR Cassete Potential Locations Amm nia/ 1 0 0 0 000 o for Air Leaving MABR Ultraviolet Disinfection Primary o a0o o 0000 Anaerobic o Clarifier Feed Then Recycled Water Clarifiers Selector Aeration Secondary orOutfall Suisun (4) Tanks Clarifiers Bay T� (4) (8) __t_tReturn Activated Sludge JWaste Activated Dewatering Sludge MABR Pilot Feed Locations and Incineration Q Phase 1 - Secondary Clarifier Influent © Phase 2 - Anaerobic Selector 0 Phase 3 - Aeration Tank MABR Pilot Water System Feed Pump from Anaerobic Selector Feed Pump from Secondary Clarifier In-proc Ammonia/ Nitrate Probes Shipping Container with MABR 02 Content Monitor """"""' ................................... Amm nia/ Level Sensor for Air Leaving MABR to Secondary Clarifier Feed Cassette Channel MABR Effluent Equalization Tank Temperature Sensor ® In-line Effluent Sample Point Pump Speed Control Air Compressor In-line for Process Air Influent Flow Sample Meter Point Flow Meters Feed Equalization Tank Overflow Drain to Secondary Clarifier Feed Channel -process Amm nia/ Nitrate Probes Effluent Drain to Secondary Clarifier Feed Channel MABR Effluent Equalization Tank June 18, 2024 Special Board Meeting Agenda Packet - Page 10 of 14 7 Page 9 of 12 MABR Pilot Air System Air goes in and out of membrane. Oxygen diffuses to biofilm. No air contact with water. Air occasionally burst from bottom of tank through water to keep tank well mixed andL �1 help control biofilm growth. 2 - 4 times per day air burst from bottom of� • tank through water for 2 - 4 minutes at a time to help control biofilm growth. 1 � � Measures % Oxygen in the Membrane Off -gas air to track transfer efficiency. Less % Oxygen ' in the off -gas means more went to biofilm. Note: Air for pilot system travels through small flexible piping and enters in bottom of tank. Routes to be shown during tour. Ammonium (NH4) Removal Has Been Successful Ammonium Influent/Effluent Concentrations 40 4 0 35 Start-up 30 i 25 i 20 2 N_ E is 10 5 0 4/5 4112 4/19 4/26 5/3 Illo 5117 524 Date t Influent Ammonium � Effluent Ammonium Well established ammonium removal after approximately 4/26/24. This is encouraging given the type of bacteria that can complete this work are not present in significant quantities in Central San's existing secondary process. June 18, 2024 Special Board Meeting Agenda Packet - Page 11 of 14 8 Page 10 of 12 Ammonium (NH4) Mass Removal Rate is Encouraging Ammonium Mass Removal Rate 3 z.s Start-up 2 g NH4-N per I.5 m2 -day I 0.5 0 4/5 4/12 4/1' 4/26 53 5/10 III' 5/24 Date The MABR potential to intensify Central San's existing secondary treatment process relies on membrane surface area that can fit into existing tankage. So far, pilot ammonium removal per square meter of membrane surface area is encouraging. I 20 Ie 16 14 12 0 10 2 g E 6 4 2 0 4/5 Nitrate Removal Has Not Been Successful at Current Feed Location Nitrate Influent/Effluent Concentrations Start-up 4/12 4/19 4/26 5/3 5/10 5117 5 24 Date Influent Nitrate Effluent Nitrate The MABR biofilm is successfully converting ammonium into nitrate. However, for TIN reduction the nitrate must be converted to nitrogen gas. This requires soluble carbon. Luckily, Central San's existing secondary process bacteria can perform this task. Central San believes this is due to a lack of carbon which can be addressed by changing feed locations. June 18, 2024 Special Board Meeting Agenda Packet - Page 12 of 14 9 MABR Process Intensification Technology Pilot Testing Near -Term Benefits Obtain Critical Design Parameters: Determine the optimal design parameters to increase nitrogen removal in the existing tanks while understanding and learning what impact cyanide, in the existing Multiple Hearth Furnace air pollution control scrubber water, has on the MABR efficiency. Timing: Better estimating the equipment location, phasing, and costs for a potential future MABR installation at Central San which would help with Nutrient Management Roadmap. MABR Pilot Results Are a Building Block I Water Reuse of the Nutrient Management 4 Roadmap Intensification MABR & Densification Optimization of Treatment Systems Performance Page 11 of 12 June 18, 2024 Special Board Meeting Agenda Packet - Page 13 of 14 10 Step 01 Define Project Goals, Issue Request for Proposal, Select Consultant and Peer Review Team Ste p 02 Identify optimization opport- unities and ways to maximize the value of existing assets 03 Narrow alternatives conduct workshops, include peer review comments, and advance the best scoring alternative Step 04 Refine best scoring alternatives and consider phasing, design, and construction Step 05 Develop Pre -Design Report and Board Nutrient Management Policy