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