alexandria renew presentation
TRANSCRIPT
Peer to Peer Exchange
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
8
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