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NVRC PresentationMay 24, 2016Karen Pallansch, Chief Executive OfficerAlexandria Renew Enterprises

Who We Are

Alexandria’s Water Transformers

• Located in an urban, landlocked landscape• Designed for 54 mgd on

just 33 acres• One of the smallest

gallon per acre sites in US

Who We Are• Created in 1952 by City Council• Independent governmental organization• Five-member appointed citizen board

3

Who We Are: AlexRenew Service Area

4

Dowden Terrace(Fairfax)

Cameron Run(Fairfax)

Jones Point(Fairfax)

Holmes RunCameron Run(City)

To ArlingtonCommonwealth

Potomac Yards

Potomac

Dowden Terrace(Falls Church)

CombinedSewerSystem

Four Mile RunP

FairfaxSewers

Fairfax Sewers in City Limits

P P

P

WRRF

LegendPumping StationP

City of Alexandria LimitsSub-watershedsCSO Service Area

• City and county own their sewer infrastructure

• AlexRenew owns pump stations, large “intercepting” sewers and Eisenhower campus

• Site neighbors:• National cemetery•Major highway• Stream• Electrical substation• Public safety• US Patent and Trade

Office• Upcoming 375’ tall

residential building• Commercial

development north/west of site

Who We Are

Discovery of Anammox

In 1932, sediments of Lake Mendota, Wisconsin, were discovered to most of the ammonia was missing due to an unknown mechanism

The bacteria causing the ammonia reduction were identified in 1999, by Delft University of Technology , in the Netherlands

What is Anammox?

• Short for “ANaerobic AMMonium OXidation”

• To reduce nitrogen, it’s a multi-step process with nitrite and nitrate as intermediate products

• Deammonification shortens the nitrogen reduction process

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How Does Anammox Work?

Ammonia(NH3/ NH4

+)

Nitrite(NO2

- )

Nitrate(NO3

- )

Amm

onia

Oxi

dize

rs

(e.g

. Nitr

osom

onas

)

75% O2

Nitri

te O

xidize

rs

(e.g

. Nitr

obac

ter)

Nitrite(NO2- )

Nitrogen Gas(N2 )

25% O2

60% Carbon

NITRITATIONAerobic , Autotrophic

40% Carbon

DENITRITATIONAnoxic, Heterotrophic

DEAMMONIFICATION

How is Anammox Used in Wastewater Treatment at AlexRenew?

• Treatment of high ammonia concentration sidestreams (dewatering centrate)

• Mainstream treatment by adding and recovering anammox bacteria to secondary treatment process

Anammox Benefits

Potential Energy reduction of up to

25%

Potential Methanol use decrease of up to 40%

Oxygen requirement for ammonia removal decrease of up to 60%

Anammox Risks

• No full-scale installations in North America• Requires precise process

monitoring and advanced controls• Process is extremely sensitive

to several environmental factors (for instance, polymer dosage variability)

Bringing Anammox to the US: Partnerships

Partnerships: Site Visit to AustriaDecember 2006 Strass WWTP

Partnerships: Dr. Bernhard Wett

• Dr. Wett retained to help with process design• Process modeling and design

parameters for DEMON system • Recommended AlexRenew install

hydrocyclones to enhance granule retention and system performance• Partnership led to contract with

DEMON GmbH

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Partnerships: The Anammox Pilot

Feed TankEffluent Tank

Insulated Reactor

Reactor

PARTNERSHIPS: FULL-SCALE SIDESTREAM ANAMMOX

AlexRenew Centrate Pre-Treatment Facility

Partnerships: Mainstream Deammonification

• Cooperative agreement with VCS Denmark

• Forward-thinking utility with shared values

• Exchange of ideas and experience

• VCS implemented mainstream anammox in 2014

• Inspired AlexRenew to launch mainstream deammonification program in U.S.

Alexandria’s Water Transformers