HomeMy WebLinkAboutSS3 - City Council Selenium Mitigation Program Presentation�I
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Selenium Mitigation
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City Council Study Session
March 812011
Public Works Department
What is Selenium?
*Selenium is a naturally occurring element.
•Selenium is an essential nutrient for animals
and some plants.
•Selenium salts are toxic in large amounts.
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Selenium Mobilization
40 POTENTIAL SOURCES OF GROUNDWATER DISCHARGE
111
RAINFALL
AGRICULTURE
UNLINED RESERVOIR �^ NON.
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IMPORTED WATER
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1_ TRUNK MAIN
GOLF COURSE
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DISTRIBUTION
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GROUNDWATER MOUND
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OVER IRRIGATION
LEAKAGE INTO S.D.
Selenium Hot Spots
NEWPORT BAY WATERSHED
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Newport Bay
Watershed Paco
Selenium TMDL Compliance
• Option One — Comprehensive Cooperative
Watershed Program
• 15 -year compliance with early action item requirement
• Develop BMP Strategic Plan
+:•San Diego Creek treatment = 5 -12 ppb
❖Big Canyon treatment = 1 ppb
❖Build Cienega Selenium Treatment Plant
❖Treat "Swamp of the Frogs" groundwater
• Total potential shared cost: $50 -150 million
Selenium TMDL Compliance
• Option Two— Compliance with Numeric Effluent
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• RWQCB assigns waste load allocation to each
responsible party
• RWQCB assigns compliance period
• Immediate compliance at tend of pipe
• Meet existing CTR limit = 5 ppb (all locations)
• Potential Newport Beach cost: $7 -10 million
Cienega Treatment Plant
Cienega Treatment Plant
Selenium inflow
Creek flow
Flow diverted to plant
Selenium concentration
at end of treatment
Treatment stream-
additional reductions
30 -120 ppb
12 cfs (average)
3 cfs (1,350 gal /min)
9 ppb (@ pipe end)
Arsenic (70 %)
Bacteria (50 %)
Copper (75 %)
Nitrates (100 %)
Zinc (100 %)
Cienega Treatment Plant
• Construction Cost Estimates - $22 -30 million
• IRWD contributes a $5.5 million Federal Grant
• IRWD operates and maintains plant
• Several scenarios being considered
❖Percent Land Area /Population Variations
•'• Proportional Distance
❖Generation and Benefiter
• Newport Beach cost $250,000 to $1.5 million
• Proposed start in Fall 2011
Big Canyon Creek
Big Canyon Strategy
• Divert Reservoir low flow under -drain and 2 HOA sub-
drains to sewer.
• Eliminate slow moving water areas
— Target Nature Park & Golf Course Lakes
— $1.5 million Irvine Company settlement
• Continue reduction in over - irrigation activities
— Audit & upgrade HOA and residential systems
— $667,000 USBR Grant
Big Canyon Strategy Continued
• Monitor effects
— Field measure total Selenium, Selenate & Selenite
— O &M Funds
• Potential Treatment Facility or Diversion at Jamboree
— Install biological reactor
— Underground wetland
— Diversion to sewer
— $1.5 million Irvine Company settlement
• Potential Overall Cost:
— $5 -7 million
Selenium Mitigation Program
Questions?