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Advanced Membrane TechnologiesStanford University, May 07, 2008Advanced Membrane TechnologiesStanford University, May 07, 2008
Membrane Technology – A Key Component in Water Reuse SystemsMehul Patel, P.E.Principal Process EngineerOrange County Water District
One Day Seminar for Treating Brackish Groundwater, Seawater, and Reclaimed Water
Stanford UniversityMay 7, 2008
Presentation OutlinePresentation Outline
►Common Reuse Applications of Membrane Technologies
►Historical Use of Membranes at OCWD►Advantages, Disadvantages, and Recommendations
for use of Membrane Technologies for Reuse Applications
►Examples of Reuse Applications: Water Factory 21 and the GWR System
Common Uses of Membrane Technology for ReuseCommon Uses of Membrane Technology for Reuse
► MF/UF used as a tertiary treatment process to meet Title 22 recycled water criteria for irrigation or industrial process water (carpet dye, paper processing)
► RO downstream of MF/UF for indirect potable reuse including seawater intrusion and surface spreading for groundwater replenishment
► Single or Two-Pass RO for ultra pure industrial processes such as boiler feed or computer chip manufacturing
► Water quality requirements govern over process costs as conventional treatment capital costs are normally less
Background On Use of RO at OCWD Background On Use of RO at OCWD
► RO used for Water Factory 21 since 1975 (RO for treatment of secondary effluent wastewater)
► Pilot scale polyamide TFC RO membranes tested downstream of MF/UF systems since 1994
► Involvement in design and initial operation of Arlington Desalter, Chino Desalter, and Tustin Desalter (RO for desalination of brackish groundwater)
► GWR System contains the largest RO system in US (70 mgd)► Partner for concept and planning of Irvine Desalter (RO for
contaminated groundwater on former Tustin Marine Corps Air Base)
Background on RO Applied Research and Testing at OCWDBackground on RO Applied Research and Testing at OCWD
► Cellulose acetate (CA) RO membranes used in WF-21 since the late 1970’s
► Pilot scale polyamide TFC RO membranes tested downstream of MF/UF systems since 1994
► Pilot scale tests using 4-inch diameter polyamide TFC elements showed lower operating pressure and higher rejection as compared with CA
► Testing also showed extended run time between cleaning due to MF/UF pre-treatment (tests also showed polyamide membranes not compatible with lime clarification pre-treatment)
Conventional Versus Advanced Water Treatment (Membrane Technologies)Conventional Versus Advanced Water Treatment (Membrane Technologies)
► Conventional treatment relies upon chemically enhanced settlement by gravity
► Disinfection is typically achieved solely through chemical addition
► Advanced treatment primarily relies upon physical separation by polymer based membranes
► Membranes offer two basic levels of treatment: particulate or dissolved contatminant removal (i.e. low pressure vs. high pressure membrane technology)
► Disinfection is achieved by chemical addition and/or altering the DNA of microorganisms
Advantages of Membrane Based TreatmentAdvantages of Membrane Based Treatment
► Footprint is typically 4 to 6 times less than conventional clarification
► Level of treatment is far greater than conventional treatment processes
► Process upsets occur less often due to nature of the treatment process
► Removal by physical separation allows for treatment of a broad range of water quality
► Allows for a high level of automation to potentially save on labor costs
Advantages of Membranes for Municipal ReuseAdvantages of Membranes for Municipal Reuse
► Most economical process for salinity reduction associated with secondary effluent (or other wastewater source) TDS levels
► Low Pressure membranes provide consistent water quality for non-potable reuse regardless of feedwater particulate content
► Stringent California DPH Draft Recharge Criteria water quality requirements best met using RO technology
► Safeguard against future contaminants of concern (i.e. Pharmaceuticals, EDC’s)
► Small footprint advantageous for areas where available land is at a premium
Disadvantages of Membrane Based TreatmentDisadvantages of Membrane Based Treatment
► Capital costs can be far greater than for conventional systems
► Current expertise of typical plant operators may not be up to level required
► Membrane replacement costs are high and must be budgeted for appropriately
► Proven track record at municipal scale is still being forged
► Concentrate and waste stream disposal issues
Roadblocks to Use of Membranes for Municipal ReuseRoadblocks to Use of Membranes for Municipal Reuse
► High initial capital costs for process equipment► O&M costs for membrane replacement► Lack of large operator level knowledge base ► Post treatment or blending issues due to corrosive nature of
product water► More economical technologies exist depending upon desired level
of treatment► Energy intensive nature makes process expensive in areas where
energy costs are high (i.e. California)
RO Is Not a Panacea: Low Molecular Weight Organic (LMWO) Rejection is not AbsoluteRO Is Not a Panacea: Low Molecular Weight Organic (LMWO) Rejection is not Absolute
► Not all LMWOs of concern are completely rejected by RO membranes
► Rejection of LMWOs is directly proportional to molecular weight and width of the compound
► NDMA is an example of a newly regulated compound not fully addressed by RO alone
► Approximately 35 - 40% of NDMA is rejected by PA TFC membranes; only 10 - 12% is rejected by CA membranes
► As lab methods improve more contaminants will be detected to far lower levels further demonstrating that RO capability to remove contaminants is not absolute
“Must Haves” if Membranes are to be Considered for Municipal Reuse“Must Haves” if Membranes are to be Considered for Municipal Reuse
► Pilot testing on source water for an extended period of time (6 months minimum for full benefit)
► Pilot testing must help establish realistic O&M costs► Thorough understanding of organic and inorganic make up of
source water► Proper pre-treatment (preferably low-pressure membrane
technology) if RO is considered► Strong membrane warranty language and technical support from
chosen MF/UF and RO manufacturer
Recommendations for Use of RO Technology for Reuse ApplicationsRecommendations for Use of RO Technology for Reuse Applications
► TDS and organics removal requirements typically drive the need for RO for reuse applications
► On-site pilot testing a must ► Level of pre-treatment determines the rate of O&M costs for RO ► State of CA water quality regulations for subsurface injection
indirectly require the use of RO► Newly regulated contaminants of concern (such as LMWOs) have
shown that RO alone may not be enough► A combination of low and high pressure membrane technology
reduces cost of possible downstream oxidation treatment (UV/peroxide, UV/Ozone, Ozone)
flocculationflocculation
clarificationclarification
recarbonationrecarbonation
filtrationfiltration
carbon adsorption (10 carbon adsorption (10 mgdmgd))
reverse osmosis reverse osmosis (5 (5 mgdmgd))
SecondarySecondarytreatedtreatedwastewaterwastewater
BlendingBlendingprior to prior to use in use in seawaterseawaterbarrierbarrier
lime sludgelime sludgeCOCO22
recycled limerecycled lime(up to 75% recovery)(up to 75% recovery)
transfertransfer thickeningthickening recalciningrecalcining
Water Factory 21 - The First Municipal Facilityto use RO for Reuse (1977 to 2004)
AOP (5 AOP (5 mgdmgd))(added later)(added later)
Water Factory 21 Conventional vs. MF/UF Treatment Prior to ROWater Factory 21 Conventional vs. MF/UF Treatment Prior to RO
GWR System – Microfiltration Pretreatment
ReverseOsmosis
Water Factory 21 – Conventional Pretreatment
Lime
Flocculation &Sedimentation FiltrationChlorinationRecarbonation
MicrofiltrationNaOCl CA vs. PA
86 86 mgdmgd70 70 mgdmgd 70 70 mgdmgd
GWR System Advanced Water Treatment Facility (AWTF) Flow DiagramGWR System Advanced Water Treatment Facility (AWTF) Flow Diagram
Ultraviolet Ultraviolet Light Light (AOP)(AOP)
Concentrate Concentrate OCSD OutfallOCSD Outfall
Backwash Backwash OCSD Plant 1OCSD Plant 1
MicrofiltrationMicrofiltration(MF)(MF)
Reverse Reverse OsmosisOsmosis
(RO)(RO)
Purified Purified WaterWater
with with hydrogenhydrogenperoxideperoxide
EnhancedSource Control
SecondaryTreatment
Surface Spreading & Seawater Intrusion Barrier
OCSD OCSD Secondary Secondary
EffluentEffluent
Lime Lime additionaddition
NaOClNaOCladditionaddition
GWR System ComponentsGWR System Components
Irvine
Fullerton
OceanOceanOutfallOutfall
OCWDOCWD
Groundwater BasinGroundwater Basin
Santa Ana River
N
Pacific Ocean
Santiago Creek
OCSDOCSDTreatmentTreatmentFacilitiesFacilities
HuntingtonBeach
AdvancedAdvancedWater PurificationWater PurificationFacilityFacility
Pumping Pumping FacilitiesFacilities
SeawaterSeawaterIntrusionIntrusion
BarrierBarrier
Kraemer BasinKraemer Basin
GWR PipelineGWR Pipeline
Future MidFuture Mid--BasinBasinInjection/RechargeInjection/Recharge
GWR System - Level of Treatment for Each ProcessGWR System - Level of Treatment for Each Process
► MF removes suspended solids, bacteria, and protozoa► MF pre-treatment increases efficiency of RO process► RO removes salinity (TDS), virus, dissolved organics► AOP process provides an additional barrier for
disinfection► AOP destructs low molecular weight organics ► Testing at OCWD has shown that the combination of
RO and AOP is effective against emerging compounds such as: low molecular weight organics, pharmaceuticals, and endocrine disruptors
AWTF Process Flow DiagramAWTF Process Flow Diagram
Microfiltration SystemMicrofiltration System
► 86 MGD Siemens CMF-S Microfiltration System (15,808 membrane modules)
► Removes bacteria, protozoa, and suspended solids
► 0.2 micron pore size
► In basin submersible membrane system
► Includes 2 CIP systems
MF System DesignMF System Design
► US Filter CMF-S system (immersed membrane)► Flux Rate = 20.4 gallons per ft2 per day► 22 minute backwash interval using reverse flow and air
agitation with complete drain of tank (cell) contents► 26 cells with 608 membrane modules each► 3 basins with 8 cells per basin (one additional basin
with only two cells)► 86 mgd total capacity► 21 day cleaning interval
GWRS CMF-S MF System Design (86 mgd)GWRS CMF-S MF System Design (86 mgd)
Train D Basins Train A Basins
Train B BasinsTrain E BasinsCell containing684 MF modules
Punch - out wall for future expansion
Empty cellsMembranes relocatedfrom temporary system
GWRS Reverse Osmosis SystemGWRS Reverse Osmosis System
►► 70 MGD Reverse Osmosis 70 MGD Reverse Osmosis System (15, 5 System (15, 5 mgdmgd units)units)
►► 15750 15750 HydranauticsHydranautics ESPAESPA--2 2 MembranesMembranes
►► Recovery Rate: 85% Recovery Rate: 85% ►► 3 3 –– stage array per unit in a stage array per unit in a
78:48:24 arrangement78:48:24 arrangement►► Removes salts, viruses, Removes salts, viruses,
organicsorganics►► Pressure range: 150 psi Pressure range: 150 psi ––
200 psi200 psi►► Includes 2 CIP systemsIncludes 2 CIP systems
RO System Process FlowRO System Process Flow
Threshold InhibitorSystem
Sulfuric Acid
System
MF Filtrate Pump
Station CIP System
Reverse Osmosis
Cartridge Filters
Concentrate to Ocean Outfall
Drain
Flush System
Feed Pump
To Post-
Treatment
Mixer
GWRS Ultraviolet Light /Advanced Oxidation SystemGWRS Ultraviolet Light /Advanced Oxidation System
►► 70 MGD Trojan 70 MGD Trojan UVPhoxUVPhoxSystemSystem
►► Low Pressure Low Pressure –– High Output High Output lamp systemlamp system
►► Nine 8.75 Nine 8.75 mgdmgd trains (3888 trains (3888 total lamps)total lamps)
►► Removes trace organicsRemoves trace organics►► Uses Hydrogen Peroxide to Uses Hydrogen Peroxide to
form an Advanced Oxidation form an Advanced Oxidation ProcessProcess
Post Treatment Process FlowPost Treatment Process Flow
To SeawaterIntrusion Barrier and Infiltration Basins
Barrier and Product Pump Stations
Decarbonators
Lime Addition(CaOH)
UV Disinfection
From ROSystem
DecarbonatorBypass
Stabilization and StorageStabilization and Storage
► Decarbonation and lime addition stabilize purified water
► GWR System water is pumped to seawater barrier and spreading basins
► Natural soil filtration and buffering provide final treatment prior to extraction after months of storage
$65.3ELA & Contingency
15.2Integrated Information System, Wells, Workshops & Insurance
19.8Phase 1 GWR System & Site Power
0.8Trailers
0.8Equipment Engineering
$480.9Total
17.1Barrier Facilities
63.2GWR Pipeline*
298.7Treatment Facilities
Escalated Cost ($M)Construction Contracts
*3 contracts
Estimated Capital CostEstimated Capital Cost
Estimated Annual O&M CostEstimated Annual O&M Cost
29.6Sub - Total
(3.8)Metropolitan Water District Subsidy
25.8Total
3.6
1.5
0.3
2.8
1.2
5.3
0.4
14.5
$ Million per Year
O&M Staff
Compliance Monitoring
UV Lamp Replacement
Membrane Replacement
Plant Refurbishment
Chemicals
Contract Maintenance
Power
Item
Federal, State, and Local FundingFederal, State, and Local Funding
Loans
$145.0► State Revolving Fund Loans
$92.5Total Grants
30.0► Department of Water Resources (Prop. 13)
37.0► State Water Resources Control Board (Prop.13)
5.0► State Water Resources Control Board
20.0► United States Bureau of Reclamation
0.5► Environmental Protection Agency
$ MillionGrants
CA DPH Regulatory Criteria for Injection
Subsurface InjectionSubsurface Injection CDPH Proposed CriteriaCDPH Proposed Criteria GWR SystemGWR System
Total Suspended SolidsTotal Suspended Solids <30 mg/L<30 mg/L NDND
FiltrationFiltration < 2 NTU< 2 NTU 0.2 NTU0.2 NTU
DisinfectionDisinfection 4 log < 2.2 total per 100 4 log < 2.2 total per 100 mLmL NDND
Underground Retention TimeUnderground Retention Time > 12 months> 12 months 24 months24 months
Horizontal SeparationHorizontal Separation > 2,000 feet> 2,000 feet 3,120 feet3,120 feet
Biochemical Oxygen DemandBiochemical Oxygen Demand < 30 mg/L< 30 mg/L NDND
Total NitrogenTotal Nitrogen < 5 mg/L< 5 mg/L 2.6 mg/L2.6 mg/L
Total Organic CarbonTotal Organic Carbon < 0.5 mg/L< 0.5 mg/L 0.26 mg/L0.26 mg/L
Drinking Water StandardsDrinking Water Standards < < MCLsMCLs < < MCLsMCLs
Department of Public Health and Regional Board Approval ProcessDepartment of Public Health and Regional Board Approval Process
► DHS Public Hearing - February 2003► DHS Findings of Fact and
Conditions► RWQCB incorporated DHS Findings
and Conditions into permit► RWQCB Hearing – March 2004 ► RWQCB issued requirements for
both Interim WF-21 and GWR System
► GWR System 70 MGD - largest IPR project in the world
Additional Requirements for GWR SystemAdditional Requirements for GWR System
► Buffer areas■ >500 ft for spreading■ >2000 ft for injection
► Retention time underground■ >6 months for spreading■ >1 year for injection
► Replacement water plan► Initial blending – 75% ramping up to 100%
RWC► Independent Advisory Panel (NWRI
appointed) for OMMP review
Water Quality Requirements for GWR SystemWater Quality Requirements for GWR System
► Comply with Drinking Water Standards plus TOC and Total N
► Non-aggressive water to reduce leaching potential
► Testing for Notification Level compounds like NDMA, perchlorate and 1,4-dioxane
► Testing for selected pharmaceuticals and endocrine disruptors
► Monitoring in plant, blend water and groundwater along flowpath to production wells
Treatment Requirements for GWR SystemTreatment Requirements for GWR System
► Enhanced Source Control by OCSD (Title 22, CCR, Division 4, Chapter 3. Recycling Criteria, Section 60320 General Requirements)
► Organics removal - <0.5 mg/L TOC ► Nitrogen removal - <5 mg/L Total N► Disinfection – UV system >4 logs virus
inactivation► UV photolysis for 1.2 log NDMA removal► AOP for unknown organic contaminants
For More InformationFor More Information
Email: [email protected]
Project Website: www.gwrsystem.com
OCWD Website: www.ocwd.com