Retro-Fit Retro-Fit Denitrification for Denitrification for Small Wastewater Small Wastewater Treatment Facilities Treatment Facilities Tenth Annual Tenth Annual Vail Professional Wastewater Operators Seminar Vail Professional Wastewater Operators Seminar Friday, October 29, 2004 Friday, October 29, 2004 Zachary J. Matyja, E.I.T. Jacobson Helgoth Consultants, Inc.
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Retro-Fit Denitrification for Small Wastewater Treatment Facilities Tenth Annual Vail Professional Wastewater Operators Seminar Friday, October 29, 2004.
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Retro-Fit Denitrification Retro-Fit Denitrification for Small Wastewater for Small Wastewater Treatment FacilitiesTreatment Facilities
Tenth AnnualTenth AnnualVail Professional Wastewater Operators SeminarVail Professional Wastewater Operators Seminar
Friday, October 29, 2004Friday, October 29, 2004
Zachary J. Matyja, E.I.T.Jacobson Helgoth Consultants, Inc.
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Presentation OutlinePresentation Outline
• Denitrification Process• Improvements at Genesee Water and Sanitation District• Implementation Process• Questions
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Denitrification ProcessDenitrification Process
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Denitrification ProcessDenitrification Process
• Ammonia (NH3)• In WW Process, Nitrogen bonds to Organic Molecules to form Ammonia-Nitrogen (NH3 & NH4)• NH3 Converted to Nitrates in Aeration Process
• Nitrates (NO3)• Common in Natural Water• Sources include: Ag Runoff, Organic Matter, WWTF Discharges• 10 mg/L Limit for Drinking Water• Can Cause “blue baby syndrome”
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Denitrification ProcessDenitrification Process
• Denitrification• The biological conversion of nitrate-nitrogen to nitrogen gas (N2), nitrous oxide (N2O), and nitric oxide (NO)• Occurs under anoxic conditions (no free oxygen available)
• Various Denitrification Processes• Attached Growth• Proprietary Processes• Single-Sludge Nitrification/Denitrification
• All modifications to existing nitrification facility take place in aeration basin• Anoxic Zone precedes Aeration• Internal Water Recycle (400-500% of Influent Flow)
Anoxic Zone(Denitrificatio
n)
RECYCLE
Aeration Zone
(Nitrification)
Influent Effluent
N2 Gas
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Effect of Recycle on Nitrate ReductionEffect of Recycle on Nitrate Reduction
• Ammonia First Passes Through Anoxic Zone• Ammonia is Converted to Nitrate in Aeration Zone• Nitrate are Recycled to Anoxic Zone• Nitrate are Converted to Nitrogen gas in Anoxic Zone
Anoxic Zone(Denitrificatio
n)
RECYCLE
Aeration Zone
(Nitrification)
InfluentEffluent
N2 Gas
NO3 Converted to N2NO3 Converted to N2 NH3 Converted to NO3NH3 Converted to NO3
• Conventional Nitrification Calculations Required First• Denitrification Calculations, Solve For
• Recycle Ratio• Aerobic / Anoxic Residence Times• Aerobic / Anoxic Tank Volumes• Aerobic / Anoxic Ratio
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Genesee Water and Sanitation DistrictWastewater Treatment Facility
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Project BackgroundProject Background
• In Foothills West of Denver, Near I-70 • District Serves 4,000+ People• Activated Sludge Facility• Discharge to Bear Creek
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Need for ProjectNeed for Project
• 2002 Drought – Low Flows in Bear Creek• Bear Creek Water Quality for Downstream Users• Potential District Water Quality Problems• Potential Water Reuse• “Stay Ahead of the Game”• Potential Future Nitrate Effluent Regulations
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Existing Wastewater Process SchematicExisting Wastewater Process Schematic
•Two Aeration Basins Operated in Parallel (0.25 MGD Capacity, Each)•Three Secondary Clarifiers Operated in Series
Aeration Basins(typ.)
ClarifierClarifier Clarifier SandFilter
Grit
Scre
enin
g
ChlorineRAS
DISCHARGE
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Existing ConditionsExisting Conditions
• Activated Sludge Facility• Design Flow 0.5 MGD• Actual Flows ≈ 0.25 MGD• Achieving Near Complete Nitrification • Previous Average Conditions:
• Baffle Wall in Aeration Basin• Install Reinforced Flexible Baffle Curtain to Divide Basins• Attached on all sides to Basin• 3’ x 4’ Hole in Bottom Corner• Furnished and Installed by Lange Containment Systems, Inc.
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Baffle Wall InstallationBaffle Wall Installation
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Denitrification DesignDenitrification Design
• Submersible Mixer• Ensure Successful Mixing of Entire Anoxic Basin• Primary purpose to keep all solids in suspension, and prevent settling in Anoxic Basin• Evaluated Two Mixers, Flygt required two mixers to accomplish same mixing• Selected USFilter EMU Uniprop
• Piping and Related Equipment• C900 PVC Pipe, Fittings, and Glue• Ductile Iron Pipe, Fittings, and Hardware• Pipe Hangers, Support Brackets, and Hardware
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Flow and Piping InstallationFlow and Piping Installation
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Denitrification DesignDenitrification Design
• Electrical Modifications• Breakers, Starters, Controls• Installed for Pump, Meter, Mixer• Installed by Sub-Contractor