New regional wastewater system
Serves rapidly growing suburban areas northeast of Seattle
Includes conveyance, treatment and marine discharge
Will produce Class A reclaimed water
BrightwaterBrightwater
General Treatment Process SchematicGeneral Treatment Process Schematic
Mixed Liquor Return to Anoxic Zone
Membrane Basins Feed
Screened Primary Effluent
RAS from Membrane Tanks to First Aerobic Zone
Foul Air Collection
Aeration Basins (bioreactor)Aeration Basins (bioreactor)
Pumped Feed to Membrane Basins
RAS from Membrane Basins to First Aerobic Zone
Gallery
Screened Primary Effluent
Aeration Zone
Foam Removal
Aeration Basins Below CoversAeration Basins Below Covers
RAS to Aeration Basins
Membrane Effluent(to disinfection)
Direction of Flow through Basins
Influent from AB’s
Odor Control Ducts
RAS to Aeration Basins
Membrane BasinsMembrane Basins
RAS to Aeration Basins
Membrane Effluent(to disinfection)
Direction of Flow through Basins
Influent Piping
20 membrane cassettes per basin
Membrane Basins Below CoversMembrane Basins Below Covers
Strands of hollow, tubular membranes are placed in biologically active aqueous effluentMembranes filter very fine solids from wastewaterEffluent is 7-10 times cleaner than secondary effluentProduct meets Class A standards for water reuse
Membrane CassettesMembrane Cassettes
Agitation air
Relax mode
Backpulse
Maintenance cleans
Recovery cleaning
Agitation air
Relax mode
Backpulse
Maintenance cleans
Recovery cleaning
Membrane MaintenanceMembrane Maintenance
Committed to “no odors at the property boundary”$65 million investmentFour Stage (liquid & vapor phase) Odor Control• Stage 1: Wastewater will be pretreated in the collection
system to reduce formation of odors• Stage 2: Bioscrubbers will remove the majority of hydrogen
sulfide and odor compounds• Stage 3: Chemical scrubbers will remove remaining odor
compounds• Stage 4: Carbon scrubbers will remove any trace odor
emissions
Odor ControlOdor Control
Stage 1(Liquid Phase Treatment) Wastewater influent pretreated with a strong form of household bleach to reduce odors
Stage 2 Stage 3 Stage 4
Odor Treatment PhasesOdor Treatment Phases
5 Parallel Trains
carbon filters bioScrubbers
chemicalscrubbers
fans
Plan View Odor Control FacilityPlan View Odor Control Facility
Odor Control FacilityOdor Control Facility
Chemical and Chemical and BioScrubbersBioScrubbers
Odor Control Fan in EnclosureOdor Control Fan in Enclosure
Foul Air
Nutrients
Foam Cubes Rolled MediaLava Rock
Mist Eliminator
Blowdown
Water Recycle or Addition
pH
Recirculation Pump
Scrubbant Sump
Treated Air
Typical Typical BioTowerBioTower(countercurrent flow)(countercurrent flow)
Selected Zenon as membrane vendorClearing, rough grading, ESC and mitigation 2006Earthwork, EDS in 2007Begin installing membranes 2009Plant testing & startup late 2010Commissioning early 2011
Selected Zenon as membrane vendorClearing, rough grading, ESC and mitigation 2006Earthwork, EDS in 2007Begin installing membranes 2009Plant testing & startup late 2010Commissioning early 2011
BrightwaterBrightwater Project ScheduleProject Schedule
Produces Class A reclaimed water to meet growing reuse demandBenefits Puget Sound through reduced annual pollutant load (“net environmental benefit”)MBR’s smaller footprint facilitates odor control, future expansion and mitigationCost competitive with conventional activated sludge (CAS) when configured as split flow process
MBR = Membrane BioReactor
Produces Class A reclaimed water to meet growing reuse demandBenefits Puget Sound through reduced annual pollutant load (“net environmental benefit”)MBR’s smaller footprint facilitates odor control, future expansion and mitigationCost competitive with conventional activated sludge (CAS) when configured as split flow process
MBR = Membrane BioReactor
Drivers for Selecting Membrane Drivers for Selecting Membrane BioReactorBioReactor
Chemically Enhanced Primary Clarification
Split Stream:
39 mgd to 130 mgd
Conventional Primary Treatment and MBR:Flows up to 39mgd
Influent EffluentPermeate
Reuse
Split Flow Treatment ConceptSplit Flow Treatment Concept
FineScreens(2 mm)
AERATION BASINS
MembraneBasins
Primary Effluent (Q)
Membrane Effluent
(Q - WAS)Pumped Feed to Membrane Basins
Gravity Flow RAS
Membrane Basins Accommodate Hollow Fiber Vendors’ Equipment
4 Q
3 Q
Basin volumes can be adjusted within secondary footprintto accommodate different membrane configurations
Key Elements of Generic Membrane Key Elements of Generic Membrane BioReactorBioReactor