Membrane Bioreactors: State of the Art and Technology …

1 Membrane Bioreactors: Membrane Bioreactors: State of the Art andState of the Art andTechnology ExchangeTechnology ExchangeR. Shane Trussell, , Shane Trussell, , for DOW ChemicalMidland, MIJune 21, 2007 OutlineOutline IntroductionIntroduction Membrane IssuesMembrane Issues Other IssuesOther IssuesOutlineOutline IntroductionIntroduction Brief historyBrief history Configurations and Configurations and manufacturersmanufacturers MBR vs. ConventionalMBR vs. Conventional Membrane IssuesMembrane Issues Other IssuesOther IssuesIntroductionIntroduction An MBR is not a An MBR is not a Membrane processmembrane process An MBR is a An MBR is a biological biological process that process that uses membranes uses membranes for solidfor solid--liquid liquid separationseparationIntroductionIntroduc tion MBRMBR ssRootsRoots Dorr Oliver (1960s)Dorr Oliver (1960s) Successfully Successfully coupled activated coupled activated sludge (AS) to sludge (AS) to Membrane separation Membrane separation by early 1970s by early 1970s (sold 27 units (sold 27 units between 1974 and between 1974 and 1982)1982)

2 EMBR process with EMBR process with flatsheetflatsheetUF UF membranesmembranes Cost prohibitiveCost prohibitive Capital and O&MCapital and O&MIntroductionIntroduction SMBR configurationSMBR configuration University of Tokyo University of Tokyo Professors Professors AyaAyaand and YamamotoYamamoto 1989 1989 WatWat.. SciSci. Tech. JapanJapan Kubota developed flatKubota developed flat--sheet SMBR sheet SMBR Mitsubishi developed Mitsubishi developed horizontal hollow horizontal hollow fiber SMBR fiber SMBR CanadaCanada ZenonZenondeveloped developed vertical hollow fiber vertical hollow fiber SMBRSMBRI ntroductionIntroduction SMBR configurationSMBR configuration Breakthrough for Breakthrough for commercialized MBR commercialized MBR technologytechnology Reduced energy by 90%Reduced energy by 90% JapanJapan Kubota dominates with Kubota dominates with 60 60 MBRsMBRsby 1996 (total by 1996 (total MGD) MGD)

3 UK, Canada, and USAUK, Canada, and USA Milton, Ontario, CA Milton, Ontario, CA 19971997 Arapahoe, CO, USA 1998 Arapahoe, CO, USA 1998 Kingston Seymour, UK Kingston Seymour, UK 19921992 IntroductionIntroduction SMBR manufacturers in the SMBR manufacturers in the USA USA --firstsfirsts ZenonZenonwas MGD in was MGD in Arapahoe, CO in 1998 Arapahoe, CO in 1998 Mitsubishi was MGD in Mitsubishi was MGD in ByfieldByfield, MA in 2000, MA in 2000 Kubota was MGD in Running Kubota was MGD in Running Springs, CA in 2002 Springs, CA in 2002 US Filter was MGD in US Filter was MGD in Lake Lake OconoceeOconocee, GAG in 2003, GAG in 2003 Zenon is the predominant MBR manufacturer with the most experience and capacity Kubota is the runner-up with significant knowledge and installation capacitySubmerged MBR (SMBR)Submerged MBR (SMBR)QPrimary Treated WastewaterWASTEE ffluentEffluentEffluentEffluentAeration BasinWaste Activated SludgeWaste Activated SludgeWaste Activated SludgeWaste Activated SludgeSolids RecycleSolids RecycleSolids RecycleSolids RecycleQR= 3-5xQExternal MBR (EMBR)External MBR (EMBR)

4 Primary Treated Primary Treated Primary Treated Primary Treated WastewaterWastewaterWastewaterWastewater Solids RecycleSolids RecycleSolids RecycleSolids RecycleEffluentEffluentEffluentEffluentA eration BasinAeration BasinAeration BasinAeration BasinQQR= 20-30xQWaste Activated SludgeWaste Activated SludgeWaste Activated SludgeWaste Activated Sludge AirAir--liftlift EMBREMBRP rimary Treated Primary Treated Primary Treated Primary Treated WastewaterWastewaterWastewaterWastewater Solids RecycleSolids RecycleSolids RecycleSolids RecycleEffluentEffluentEffluentEffluentA eration BasinAeration BasinAeration BasinAeration BasinQQR= 5-10xQWaste Activated SludgeWaste Activated SludgeWaste Activated SludgeWaste Activated SludgeDiffuserDiffuserDiffuserDiffuserZE NONZENON Hollow fiber Hollow fiber Membrane Membrane configurationconfiguration Proprietary Proprietary polymerpolymer UltrafiltrationUltrafiltration 1998 First MBR 1998 First MBR Installation in Installation in the USA was the USA was operational at operational at MGD in MGD in Arapahoe, COArapahoe, COZENONZENON 48 modules combine 48 modules combine to form a cassetteto form a cassette One common headerOne common header Permeate drawn Permeate drawn from top and from top and bottombottom Intermittent Intermittent coarse bubble coarse bubble aeration (10s on/ aeration (10s on/ 10s off)10s off)

5 ZENONZENON Membranes submerged at end of aeration basinMembranes submerged at end of aeration basin System capable of operating with System capable of operating with backpulsebackpulse or or relaxrelax Kubota / Kubota / EnviroquipEnviroquip Flat sheet Membrane Flat sheet Membrane configurationconfiguration PolyethylenePolyethylene MicrofiltrationMicrofiltration 2002 First MBR 2002 First MBR Installation in the Installation in the USA was operational USA was operational at MGD in at MGD in Running Springs, CARunning Springs, CAKubota / Kubota / EnviroquipEnviroquip 100 flat sheets 100 flat sheets combine to form combine to form cassettecassette Each sheet has Each sheet has tube connection tube connection to headerto header Constant coarse Constant coarse bubble aeration bubble aeration to mitigate to mitigate Membrane foulingmembrane foulingKubota / Kubota / EnviroquipEnviroquip Cassette submerged in aeration basinCassette submerged in aeration basin Double Double deckerdecker(DD) configuration(DD)

6 Configuration System operates with Membrane relax, no System operates with Membrane relax, no backpulsebackpulseUS Filter/ US Filter/ MemJetMemJet Hollow fiber Hollow fiber Membrane Membrane configurationconfiguration PVDF PVDF MicrofiltrationMicrofiltration 2003 First MBR 2003 First MBR Installation in the Installation in the USA was operational USA was operational at MGD in Lake at MGD in Lake Oconee, GAOconee, GAUS Filter/ US Filter/ MemJetMemJet Bundles of 4 Bundles of 4 Membrane modulesmembrane modules Common header for 4 Common header for 4 modulesmodules Combination of Combination of air/liquid jet air/liquid jet Jet Jet TechTech is used to is used to provide crossprovide cross--flow flow to the Membrane to the Membrane surfacesurfaceUS Filter/ US Filter/ MemJetMemJet Separate tank Separate tank for membranesfor membranes Backwashing Backwashing cycle:cycle.

7 45 s relax45 s relax15 s permeate 15 s permeate backflushbackflush15 s coarse 15 s coarse bubble airbubble airMitsubishi / GE IonicsMitsubishi / GE Ionics Hollow fiber Membrane Hollow fiber Membrane configuration configuration (horizontal)(horizontal) PolyethylenePolyethylene MicrofiltrationMicrofiltration 2000 First MBR 2000 First MBR Installation in the Installation in the USA was operational USA was operational at MGD in at MGD in ByfieldByfield, MA, MAMitsubishi / GE IonicsMitsubishi / GE Ionics 50 Membrane modules 50 Membrane modules for 1 Membrane bankfor 1 Membrane bank Modules connect to Modules connect to common headercommon header Permeate drawn from Permeate drawn from both sides (L and R)both sides (L and R) Constant coarse Constant coarse bubble aerationbubble aerationMitsubishi / GE IonicsMitsubishi / GE Ionics Membranes submerged in aeration basinMembranes submerged in aeration basin System operates with Membrane relax, no System operates with Membrane relax, no backpulsebackpulseMembrane ComparisonMembrane FilterUS Membrane Area/Footprint,Area/Footprint,ftft22/ft/ ft22 Absolute Absolute MWCO,MWCO, mmNominal Nominal MWCO,MWCO, mmManufacturerManufacturerKoch Koch PuronPuronEMBREMBR ss ReRe--BirthBirth --Air PumpsAir PumpsHow does MBR compare How does MBR compare to what is to what is commoncommon wastewater practice?

8 Wastewater practice?Drivers for Process Drivers for Process SelectionSelection Intended use of treated waterIntended use of treated water Effluent limitsEffluent limits Scalability Scalability Site constraintsSite constraints Flexibility with Flexibility with expansions/retrofitsexpansions/retrofits Capital costCapital cost O&M costO&M cost Training/Expertise requirementTraining/Expertise requirementTechnologiesTechnologiesGoal is to remove COD, TN, TSS, Goal is to remove COD, TN, TSS, and Pathogensand PathogensSmall to medium capacity < 5 MGDS mall to medium capacity < 5 MGD Oxidation DitchOxidation Ditch Sequencing Batch Reactor (SBR)Sequencing Batch Reactor (SBR) Membrane bioreactor (MBR) Membrane bioreactor (MBR)Large capacity > 5 MGDL arge capacity > 5 MGD Conventional activated sludgeConventional activated sludge Pure oxygen activated sludgePure oxygen activated sludge Membrane bioreactor (MBR) Membrane bioreactor (MBR)

9 Flow Scheme for Conventional Flow Scheme for Conventional Activated Sludge ProcessActivated Sludge ProcessBackwash WaterSecondaryClarifierSecondaryClarifie rWASTEToDisinfectionMicrofiltrationConve ntionalConventionalAeration BasinAeration BasinPrimary Treated WastewaterFlow Schemes for the MBR and Flow Schemes for the MBR and Conventional Activated Sludge Conventional Activated Sludge ProcessProcessPrimary Treated WastewaterBackwash WaterSecondaryClarifierWASTEToDisinfecti onMicrofiltrationConventionalAeration BasinWASTEMBRA eration BasinToDisinfectionSequencing Batch Sequencing Batch ReactorsReactors SBR is a fillSBR is a fill--and draw type and draw type activated sludge systemactivated sludge system Equalization, aeration and Equalization, aeration and clarification all performed in the clarification all performed in the same batch reactorsame batch reactorReactSettleDecantRetrofitting SBR with MBRC apacity increases by 8-fold Batch becomes Continuous MLSS increases from 3 to 10 g/LDisinfectionPrimary Treated WastewaterWaste Activate SludgeMembrane TankAeration TankSolids RecycleQR= 3-5 QQOxidation DitchOxidation DitchOxidation ditch is an activated sludge processthat utilizes long solids retention timesCAS SRT = 5 avg.

10 DaysOxidation ditch SRT = 20 avg. daysOxidation DitchOxidation Ditch Double Ditch Triple Ditch Mechanical aerators More capacity, more ditches Typical HRT is 24 hTechnologiesTechnologiesAll conventional technologies that compete with MBR use gravity for solid-liquid separation Additional filtration process required to Additional filtration process required to attain recycled water statusattain recycled water status Membrane filtration required to attain a Membrane filtration required to attain a similar water qualitysimilar water quality MBR has great potential to reduce MBR has great potential to reduce disinfection requirements disinfection requirements Commercial MBRs to date are not marketed in in a manner that allows operation similar to pure oxygen plants Low SRT operation to prevent nitrification Low SRT operation to prevent nitrification and significantly reduce