1. Retro-Fit Denitrification for Small Wastewater Treatment Facilities
Tenth Annual
Vail Professional Wastewater Operators Seminar
Friday, October 29, 2004
Zachary J. Matyja, E.I.T.
Jacobson Helgoth Consultants, Inc.
Jacobson Helgoth Consultants, Inc.

2. Retro-Fit Denitrification Improvements
Presentation Outline
Denitrification Process
Improvements at Genesee Water and Sanitation District
Implementation Process
Questions 2
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3. Retro-Fit Denitrification Improvements Denitrification Process3
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4. Retro-Fit Denitrification Improvements Denitrification 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” 4
Jacobson Helgoth Consultants, Inc.

5. Retro-Fit Denitrification Improvements Denitrification Process
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 5
Jacobson Helgoth Consultants, Inc.

6. Retro-Fit Denitrification Improvements
Single-Sludge Nitrification / Denitrification
All modifications to existing nitrification facility take place in aeration basin
Anoxic Zone precedes Aeration
Internal Water Recycle ( % of Influent Flow)
N2 Gas
RECYCLE
Influent
Anoxic Zone
(Denitrification)
Aeration Zone
(Nitrification)
Effluent 6
Jacobson Helgoth Consultants, Inc.

7. Retro-Fit Denitrification Improvements
Effect of Recycle on Nitrate Reduction 7
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8. Retro-Fit Denitrification Improvements Denitrification Chemistry
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
NO3 Converted to N2
NH3 Converted to NO3
N2 Gas
RECYCLE
Effluent
Influent
Anoxic Zone
(Denitrification)
Aeration Zone
(Nitrification) 8
Jacobson Helgoth Consultants, Inc.

9. Retro-Fit Denitrification Improvements Denitrification Calculations
Conventional Nitrification Calculations Required First
Denitrification Calculations, Solve For
Recycle Ratio
Aerobic / Anoxic Residence Times
Aerobic / Anoxic Tank Volumes
Aerobic / Anoxic Ratio 9
Jacobson Helgoth Consultants, Inc.

10. Retro-Fit Denitrification Improvements
Genesee Water and Sanitation District
Wastewater Treatment Facility
1010
Jacobson Helgoth Consultants, Inc.

11. Retro-Fit Denitrification Improvements
Project Background
In Foothills West of Denver, Near I-70
District Serves 4,000+ People
Activated Sludge Facility
Discharge to Bear Creek
1111
Jacobson Helgoth Consultants, Inc.

12. Retro-Fit Denitrification Improvements
Need 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
1212
Jacobson Helgoth Consultants, Inc.

13. Retro-Fit Denitrification Improvements
Existing Wastewater Process Schematic
Two Aeration Basins Operated in Parallel (0.25 MGD Capacity, Each)
Three Secondary Clarifiers Operated in Series D I S C H A R G E
Screening
Clarifier
Clarifier
Clarifier
Grit
Aeration Basins
(typ.)
Sand
Filter
Chlorine
RAS
1313
Jacobson Helgoth Consultants, Inc.

14. Retro-Fit Denitrification Improvements
Existing Conditions
Activated Sludge Facility
Design Flow 0.5 MGD
Actual Flows ≈ 0.25 MGD
Achieving Near Complete Nitrification
Previous Average Conditions:
Influent Effluent Limits
Ammonia (mg/L) <
Nitrates (mg/L) < None
1414
Jacobson Helgoth Consultants, Inc.

15. Retro-Fit Denitrification Improvements
Denitrification Calculation Results
Estimated Recycle Ratio = 295%
Aerobic Residence Time Required = 4.8 hours
Anoxic Residence Time Required = 2.0 hours
Aerobic Tank Volume Fraction = 71%
Anoxic Tank Volume Fraction = 29%
1515
Jacobson Helgoth Consultants, Inc.

16. Retro-Fit Denitrification Improvements Denitrification Design Drawings
1616
Jacobson Helgoth Consultants, Inc.

17. Retro-Fit Denitrification Improvements Denitrification Design
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.
1717
Jacobson Helgoth Consultants, Inc.

18. Retro-Fit Denitrification Improvements Baffle Wall Installation
1818
Jacobson Helgoth Consultants, Inc.

19. Retro-Fit Denitrification Improvements Denitrification 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
1919
Jacobson Helgoth Consultants, Inc.

20. Retro-Fit Denitrification Improvements
Mixer Installation
2020
Jacobson Helgoth Consultants, Inc.

21. Retro-Fit Denitrification Improvements Denitrification Design Drawings
2121
Jacobson Helgoth Consultants, Inc.

22. Retro-Fit Denitrification Improvements Denitrification Design Drawings
Piping Design From Pump
2222
Jacobson Helgoth Consultants, Inc.

23. Retro-Fit Denitrification Improvements Denitrification Design
Submersible Pump
Designed for 900 gpm, 10’ TDH
5 hp, 1750 rpm, submersible motor
Guide Rails to Raise Pump
ITT Flygt Submersible Sewage Pump Purchased
2323
Jacobson Helgoth Consultants, Inc.

24. Retro-Fit Denitrification Improvements
Pump Installation
2424
Jacobson Helgoth Consultants, Inc.

25. Retro-Fit Denitrification Improvements Denitrification Design
Flow Measurement
Electromagnetic Flow Meter –
Endress + Hauser, Promag 50W
Flow Control
Ballcentric Plug Valve with Handwheel Gear – Pratt
Piping and Related Equipment
C900 PVC Pipe, Fittings, and Glue
Ductile Iron Pipe, Fittings, and Hardware
Pipe Hangers, Support Brackets, and Hardware
2525
Jacobson Helgoth Consultants, Inc.

26. Retro-Fit Denitrification Improvements Flow and Piping Installation
2626
Jacobson Helgoth Consultants, Inc.

27. Retro-Fit Denitrification Improvements Denitrification Design
Electrical Modifications
Breakers, Starters, Controls
Installed for Pump, Meter, Mixer
Installed by Sub-Contractor
2727
Jacobson Helgoth Consultants, Inc.

28. Retro-Fit Denitrification Improvements Denitrification Installation
Aeration Basin Offline
Basin Power Washed
Diffusers Removed / Plugged
Baffle Wall Installed by Sub-Contractor
Pump, Piping, Mixer Installed
Electrical Hook-up by Sub-Contractor
200 Man-Hours by District Staff
100 Man-Hours Electrical Sub-Contractor
300 Man-Hours Total
2828
Jacobson Helgoth Consultants, Inc.

29. Retro-Fit Denitrification Improvements
Denitrification Results at Genesee
Current Recycle Rate set at ≈ 230%
Effluent Nitrate Levels 3-5 mg/L (78% Reduction)
2929
Jacobson Helgoth Consultants, Inc.

30. Retro-Fit Denitrification Improvements
Additional Benefits found at Genesee
A Substantial Decrease in Added Alkalinity Requirements has been Noted
Alkalinity is recovered in Recycled Water in Anoxic Zone
Better Settling and Clarity has been Noted in Clarifiers
A Decrease in Aluminum Sulfate Usage has been Noted
Due to Increased Biological Phosphorous Uptake
More Effective Dewatering Process (Centrifuge)
Reduced Air Requirement in Aeration Basins
3030
Jacobson Helgoth Consultants, Inc.

31. Retro-Fit Denitrification Improvements
Negatives to Denitrification found at Genesee
Initial Electrical Consumption has increased 15%
From Pump, Mixer, and Meter Usage
May Decrease because of Reduced Air Requirements
Initial Operation Requirements to Determine Recycle Ratio
More Frequent Monitoring for Filamentous Control in the Anoxic Zone
3131
Jacobson Helgoth Consultants, Inc.

32. Retro-Fit Denitrification Improvements
Total Costs
$46,000 for One (0.25 MGD) Aeration Basin Conversion
Engineering – $ 6,500
Baffle Wall – $ 6,200
Pump & Equip. – $ 4,900
Jib Crane & Trolley – $ 1,400
Mixer & Equip. – $10,300
Flow Meter – $ 2,900
Plug Valve – $
Pipe, Supports, Etc. – $ 3,300
Electrical – $ 9,900
3232
Jacobson Helgoth Consultants, Inc.

33. Retro-Fit Denitrification Improvements Design Implementation
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Jacobson Helgoth Consultants, Inc.

34. Retro-Fit Denitrification Improvements Design Implementation
Determine Need
Establish Funding
Engineering Calculations / Design
Equipment / Materials Selection
Determine Resources Available
Installation
Financial / Chemical Changes
3434
Jacobson Helgoth Consultants, Inc.

35. Retro-Fit Denitrification Improvements
Questions?
Zach Matyja
Jacobson Helgoth Consultants, Inc.
(303)
3535
Jacobson Helgoth Consultants, Inc.