October 27, 2010

Pacific Northwest Clean Water Association77th Annual Conference & Exhibition, Bend, Oregon

The Home Stretch:The Home Stretch: Approaching StartApproaching Start--Up of a State of the Art, Up of a State of the Art, Sustainable MBRSustainable MBR

Jason Diamond, P.Eng.

GE –

ZENON Membrane Solutions

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Presentation Outline

AcknowledgementsMembranesMembrane Bioreactors (MBRs)Tri-City MBR Expansion ProjectTri-City MBR Start-UpQuestions

AcknowledgementsAcknowledgements

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Thanks!

Jude D. Grounds, MWH

Michael Trent, WES - Clackamas County

Dale Richwine, Richwine Environmental, Inc.

Chris Allen, GE-ZENON

Sharina Naidoo, GE-ZENON

MembranesMembranes

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Membranes are all around us

Synthetic membranes can

remove harmful bacteria and pathogens from

drinking water sources

Natural membranes can be found in living organisms such as human cells. They allow nutrients to enter while rejecting toxins and other waste products

Synthetic membranes can be made from polymer, ceramics and other porous material. They are used for a wide variety of filtration applications.

Tri-City MBR membranes are hollow fibers of porous polymer with billions of microscopic pores on the surface

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Membrane Configurations

Spiral wound/tubular: best suited to NF/RO

Hollow fiber: best suited for MF/UF

Sand filtrationSand filtration

MicrofiltrationMicrofiltration

UltrafiltrationUltrafiltration

NanofiltrationNanofiltration

Reverse OsmosisReverse Osmosis

0.0001 0.001 0.01 0.1 1 10 100um

Flat plate

Reverse Osmosis

Tri-City MBR membrane range

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How do Membranes Work?

Contaminants such as bacteria and viruses can not pass through the membrane’s pores

Water molecules and dissolved salts pass freely through the membrane pores

Semi permeable membrane wall with microscopic pores

Membrane Bioreactors Membrane Bioreactors (MBRs)(MBRs)

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Membrane Bioreactor (MBR)

ActivatedSludgeProcess

MembraneFiltration

MBR

Stable BiologicalTreatment Process

Absolute SolidsSeparation

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MBR System Overview

Distribution Channel

Membrane Aeration

Permeate PumpingMixed Liquor RecirculationBioreactor

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MBR Drivers

Rapid population growth & urban sprawlNew and very stringent discharge & reuse limitsTight budgetsLimited spaceInfrastructure upgradesEnvironmental restoration

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The MBR System

Fiber

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Membrane Cassette

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MBR Train

Air blower

Permeate pump

Membrane cassettes

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Tri-City WPCP Membrane Area

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Tri-City WPCP Membrane Train 2b

Air lines

Permeate pipe

Isolation valves

Membrane cassettes to be immersed in

tank

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Basic MBR System Design Comparisons with ASPs

Conv.

MBRMLSS

<3000 mg/l <15000 mg/l

HRT

12 – 20 hrs 2 – 6 hrs

SRT

<15 d 10+ d

Biological sludge yield

>80% <80%

Bioreactor volume

4 times smaller

Clarifier

Primary / Secondary None (Primary optional)

Tertiary treatment

Sand filtration / UV UF permeate

Overall footprint

>4 times smaller

Process stability

Settlement problems Not susceptible

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Process Advantages

Highly aerobic process• Build community friendly plants with nearby residences

and recreational paths

Operational reliability• Performance is independent of sludge settling

characteristics. Year round nitrification is ensured.

Reduces sludge yield• High SRT operation is possible

Ideal for staged expansion• Modular design approach, selected loading

parameters (MLSS) and hydraulic capacity (membrane area)

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Conventional Treatment Membrane Treatment

Reduced Footprint - Wastewater

Comparison for a 7.5 mgd WWTP

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• BOD < 3 mg/L (typically non-detectable)• TSS < 3 mg/L (typically non-detectable) • NH3-N < 0.5 mg/L • TP < 0.05 mg/L (requires coagulant addition)• TN < 3 mg/L (may require supplemental carbon)• Turbidity < 0.2 NTU

MBR Effluent Quality

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The Usual MBR Environment

A B C D

A –

Raw Sewage B –

Aeration Tank

C –

Membrane Tank D –

MBR Permeate

TriTri--CityCity WPCP MBR ExpansionWPCP MBR Expansion

Bioreactor

Membrane Trains

Effluent to Discharge

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Tri-City WPCP

Oregon City, ORMap courtesy of www.mapquest.com

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Project ObjectivesProject ObjectivesTri-City WPCP MBR Expansion

The MBR portion has a design capacity of 4.0 MGD

• Site planning allows for future expansion of MBR capacity to 24.0 MGD

• ‘Stepped Expansion’

to provide both additional treatment capacity and additional reuse water supply on an as-needed basis

• Increases treatment capacity of WPCP while adding a sustainable supply of high quality effluent

• Energy efficiency and system sustainability given high level of consideration in project decisions:

• Equipment selection

• Site design and construction –

green roofs, pervious pavement, bioswales, green streets and stormwater

retention

• Educational opportunities

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ObjectivesObjectives

To develop an innovative and compact MBR system by minimizing plant footprint

To meet stringent reuse water quality and increase capacity

To achieve cost-effective and reliable solutions efficiently and sustainably

Include planning for future expansions

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TriTri--City WPCPCity WPCP

MBR Expansion

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TriTri--City WPCP City WPCP –– Interim Interim ExpansionExpansion

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MBR Design ParametersParameter Effluent Quality

BOD5 < 5 mg/L

TSS < 5 mg/L

Ammonia -

Nitrogen

< 1 mg/L

Total Nitrogen n/r

Turbidity < 0.5 NTU (100%)

< 0.2 NTU (95%)Temperature ≥

12

OC

Design Conditions

Capacity

ADF 4.0 MGD

MMF 6.0 MGD

MDF 9.0 MGD

PHF 10.0 MGD

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MBR Membrane DesignMBR Membrane Design

ZeeWeedZeeWeed®®

MBR SystemMBR System

Membrane Type Hollow Fiber

ZeeWeed®

Module ZW 500d

Number of Trains 4

Cassettes Per Train 9

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Existing Plant StructureExisting Plant StructureOperating at up to 8.4 MGD

Existing Conventional Activated Sludge Process included:

– Influent pumping station– Headworks– Primary clarifiers– Aeration basins– Secondary clarifiers– Disinfection– Solids handling

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Components of ZW MBR PlantComponents of ZW MBR PlantZeeWeed® MBR Process

BioreactorZeeWeedTank

RawSewage

Fine Screen

Waste SludgeTreatment

Permeate FinalEffluent

Disinfection

Sludge Disposal

Recirculation

Anoxic Aerobic

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Tri-City WPCP MBR Configuration

Single biological lane (Conventional aeration basin can be used temporarily with MBR for maintenance)

4 parallel membrane trains

Denitrification included to minimize chemical use (low alkalinity)

R2 Q

QQ Q(R2 +1)

Anoxic Aerobic

DO > 1 mg/LNH4

+→NO3-NO3

- → N2

DO < 0.5 mg/L

Waste Sludge (1%wt MLSS)

MembraneTank

DO = 2-5 mg/L

R1 Q DO = 1-2 mg/L

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HeadworksHeadworks

Headworks

JWC 2-mm internally fed travelling band screens

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Aeration Equipment

HSI High-Speed Turbo Blowers

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Aeration Basin

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Recirculation Pumps

WEMCO HydroSTAL pumps

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Membrane AreaMembrane Area

Membrane Zone

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Filtrate Pumps

Goulds 3196

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Filtrate DisinfectionFiltrate Disinfection

Disinfection & Discharge

IDI Aquaray® 3X UV Disinfection

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TriTri--City WPCP City WPCP –– Site ToursSite Tours

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Effluent QualityEffluent Quality

ParameterParameter InfluentInfluent[mg/L][mg/L]

EffluentEffluent[mg/L][mg/L]

BODBOD55 170170 ≤≤

5.05.0

TSSTSS 150150 ≤≤

5.05.0

AmmoniaAmmonia 5050 ≤≤

11

TurbidityTurbidity N/AN/A ≤≤

0.2 NTU0.2 NTU

TriTri--City WPCPCity WPCP MBR StartMBR Start--UpUp

Bioreactor

Membrane Trains

Effluent to Discharge

Membrane Bioreactor Commissioning, Seeding and

Start-Up

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Key Terms:

Commissioning:

Testing of equipment installation and operation, verification of controls and equipment integration

Seeding:

Providing or developing a biomass concentration capable of treating the wastewater

Start-Up:

Begin processing of wastewater, developing system to meet required wastewater capacity and effluent quality

Tri-City WPCP MBR Commissioning

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CommissioningMajor construction complete or at a stage sufficient to start testing MBR equipment

GE-ZENON Field Service Representative (FSR) on-site to perform the following tasks:

– Installation Verification– I/O Verification– Membrane Installation– Scenario Testing With Clean Water

Install membranes

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Typical MBR Fine Screens

In-channel Rotary Drum ScreenInternally Fed Rotary Drum Screen

Rotating Brush Screen

Traveling Band Screenafter Primary Clarifier

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TriTri--City WPCP MBR Fine City WPCP MBR Fine ScreensScreens

JWC 2-mm internally fed travelling band screens

2-mm internally fed band screens

Fine screening more critical for MBR than conventional – protection for membranes

First system brought on-line to treat plant seed and condition MLSS for membranes as well as influent

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TriTri--City WPCP MBR Fine City WPCP MBR Fine ScreensScreens

JWC 2-mm internally fed travelling band screens

Existing conventional system meant mixed liquor was available on-site for seeding plant quickly

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Commissioning Complete / Pre-Seeding Checklist

Seeding and Start-Up Workplan (site specific) developed?

System fully water tested (Controls 100% complete)?

Influent screen functioning properly (if required)?

Recirculation pumps functioning properly (3 – 10Q, typical 5Q)?

Blowers functioning properly?

Aeration pattern – fine bubble diffuser grid?

Aeration patter – membranes?

Analytical test equipment – site lab or external lab.?

Calibrate on-line analytical equipment – DO, pH etc?

Dial out alarm?

Logsheet, spreadsheet with graphs?

Operator Training?

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Commissioning - Tri-City Membrane Installation

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Commissioning - Tri-City Membrane Installation

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Commissioning - Tri-City Membrane Installation

Tri-City WPCP MBR Seeding

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Seeding Considerations

Membrane Fouling can occur – organic and inorganic

– proceed with a degree of caution

– have cleaning chemicals available

Foam may occur during seeding

Typical biological seeding duration 2 – 6 weeks

– Exception: 1 day

Typical biological seed is mixed liquor transferred from operational WWTP

– Exceptions: can be developed on-site from raw wastewater or purchase freeze-dried seed

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Typical MBR Seeding Procedure

1. Submerse membranes in water before seeding and ensure they are covered at all times

2. Transfer mixed liquor into tank to achieve the minimum MLSS required by the membrane supplier and to achieve a reasonable F:M (ie 0.2 kg BOD5 /kg MLVSS at 20C). Note - some membrane designs require a minimum MLSS of 3 g/L or higher

3. Screen the seed sludge while transferring to bioreactor

4. If in tank equalization is available, it may be beneficial to batch feed system during early seeding rather than continuously feed

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Typical MBR Seeding Procedure

5. Maintain reasonable F:M while increasing the flow and MLSS.

6. Operate initially at a reduced flux to minimize membrane fouling

7. Monitor MLSS, effluent ammonia, COD and/or other indicators before increasing the influent flow.

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Tri-City WPCP MBR Seeding Procedure

Transfer MLSS from operational conventional plant through fine screens

Tri-City WPCP MBR Start-Up –

Operation and

Monitoring

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Key Terms:

Flux:

Amount of flow per day per square foot of membrane GFD (Gallons/sqft/day)

TMP:

Transmembrane Pressure. Amount of Vacuum drawn across membrane (psi)

Permeability:

Permeability is a measure of how much water is being drawn per unit of pressure (gfd/psi)

Membrane Performance Monitoring

Key membrane process parametersFlow through the membrane per unit surface area -

Flux

Transmembrane pressure (TMP)

Cleaning method and cleaning frequency

Monitoring membrane performance

Instantaneous permeability

Effluent quality - Turbidity

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Normal Operation

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MLSS Distribution – 8 g/L in bioreactor

0

2

4

6

8

10

12

14

16

1 2 3 4 5 6 7 8 9 10

Recycle Rate (RQ)

Mem

bran

e Ta

nk M

LSS

(g/L

)

Design

MLSSmembrane

tank = (R+1)

x MLSSbioreactorR

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Analytical Tools

COD

NH3 , NO3

MLSS, MLVSS

DO

Time to Filter (TTF)

OUR

pH

Alkalinity

Turbidity

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Typical Analytical Objectives

OUR: 20 - 100 mg/L/hr

pH: 6.5 – 8.0

Permeate COD: 20-50 mg/L (industrial could be 1000 mg/L)

Permeate NH3 -N: <1 mg/L

Permeate NO3 : 1 – 30 mg/L (denitrification required?)

Alkalinity: > 50 mg/L

Time To Filter (TTF) < 150 seconds

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Ensure nitrification (i.e. NH3 < 1 and SRT > 12-d)

DO > 1.5 mg/L in the aerobic and membrane tank

Avoid sudden changes in environmental conditions (pH, loading, etc.)

Monitor Time-To-Filter (TTF)

How to Promote Good Membrane Performance and Sludge Filterability

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Physical Operating Conditions

Inspect and maintain influent screensOperate membranes at proper relax or backpulse frequenciesEnsure proper membrane aerationPlugging or clean aeratorsRecirculation Rate and solids balanceInspect cassettes Perform membrane cleaning as recommended by vendor

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Work with vendor to develop a start up plan and ideally have them on site.

Ensure pretreatment is operating at seeding, startup and operation

Be aware that the biological performance is integral to membrane performance• Monitor key parameters

Allow time for seeding and time to build solids before any deadlines

Start-Up Key Points

Project CompletionProject Completion

Construction wrapping up

Membranes installed and wet-testing

Seeding and wastewater processing expected for November

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Thank You!Thank You!

Questions?Questions?