Lessons Learned from BNR Upgrades

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1 OWEA Annual Conference Lessons Learned from BNR Upgrades What should be on your checklist? W. James Gellner, PE

2 Acknowledgements - Utilities Mason Farm WWTP (OWASA) Damon Forney and Vishnu Gangadharan City of Greensboro Don Howard, Kenny McDowell, and Wally Kling Nansemond WWTP Bill Balzer, Charles Bott, and Rick Baumler Henrico County WRF James Grandstaff, Carol Danforth, and Michael Chapman City of High Point Eastside WRF Terry Houk and Chris Thompson Arlington East WRF - David Kowalski, Colin Groff, and Scott Kelly Moores Creek WWTP (Rivanna WSA) Tom Frederick, Jennifer Whitaker, Cary Lang, and Robert Wichser

3 The Magnificent Seven Remix

4 Acknowledgements Hazen and Sawyer Paul Pitt, San Francisco, CA Ron Latimer, Atlanta, GA Katya Bilyk, Raleigh, NC Joe Rohrbacher, Charleston, SC Alonso Griborio, Hollywood, FL Theresa Bruton, Baltimore, MD Phill Yi, Fairfax, VA

5 OWASA Mason Farm WWTP, NC

6 Challenge: How to Economically Meet TN of 3 mg/l and TP of 0.23 mg/l 14.5 mgd WWTP ~ 7.7 mgd current ADF Sludge nutrification process Denitrification filters Effluent TN ~15 mg/l High chemical costs $700,000/year NaOH, Alum, acetic acid

7 Approach Data characterization and supplemental sampling Developed calibrated process model Process optimization 3D 4A 4B Alum (ISS) 25% NaOH 3A 2D 2C Influent AB Inf. Channel 1E 1F 2B Effluent Channel #1 Cell 5 Effluent Channel #2 Plant Effluent 20% HAc Nutrification 1D Nutrification 1C Primary Fermenter Alum (ISS) Anaerobic Digesters Sludge Storage Liquid Biosolids Dewatered Cake

8 Solution: Reduce Secondary Effluent TN by Changing Influent Flow and Aeration Pattern Operate as step feed BNR Reduce secondary effluent TN Decreases carbon addition to filters Reduces future dependence on deep bed filters More alkalinity recovery Reduced aeration

9 Results: 40% Reduction in TN Parameter Pre-Transition Step Feed Influent Flow (mgd) cbod 5 (mg/l) < 3 < 3 TSS (mg/l) 1 1 NH 3 -N (mg/l) < 0.5 < 0.5 TKN (mg/l) NO x -N (mg/l) Total Nitrogen (mg/l) Total Phosphorus (mg/l)

10 Results: $225,000/yr savings in Chemical Costs, $822,000/yr est. Future Savings Current Annual Savings Future Annual Savings (TN = 3 mg/l) 48% Alum $33,000 $42,000 25% Sodium Hydroxide $127,000 $265,000 20% Acetic Acid $64,000 $515,000 Total Annual Savings $224,000 $822,000

11 Lesson Learned: Make the Best use of the Influent Carbon Optimize denitrification to decrease alkalinity addition Utilize carbon sources inherent in wastewater to reduce supplemental carbon usage Primary effluent Primary sludge fermentation RAS fermentation (current project)

12 Greensboro, NC *1

13 The Challenge: How to Comply with Future TN Limit of 5.3 mg/l, TP of 0.66 mg/l TZ Osborne - 40 MGD North Buffalo Creek 16 MGD Design flow total 56 MGD (25 year window) Need to meet future capacity and nutrient requirements Greensboro

14 Approach: Master Plan (2006) Showed Significant Cost Savings with IFAS Flow to TZO 40 MGD 46 MGD 56 MGD IFAS Cost Savings over Conventional Activated Sludge ($M) 30% Aerobic Volume Savings $-2M 50% Aerobic Volume Savings $-2M $-0.5M $9M $-0.5M $18M Minimal additional volume for capacity at TZO

15 Solution: Pilot IFAS to Determine if Cost Savings at Study Level are Real RAS To Final Clarifier IFAS Cell 1 IFAS Cell 2 IFAS Cell 3 A B C D E F G H I ~ 35% media fill 3 distinct zones Screens for each cell Replaced fine bubble aeration

16 One Year Pilot Study Pilot Testing 3.5 MGD Design Flow Weekly profile sampling Nitrification batch tests Biomass on media testing Confirmed volume savings

Lessons Learned: Pilot New Technology When There is

costs for IFAS technology Screen head loss twice expected

aeration rates in IFAS zones (up to 3 x) True O&M costs

17 Lessons Learned: Pilot New Technology When There is Uncertainty Pilot study allowed evaluation of true O&M costs for IFAS technology Screen head loss twice expected Foam management Fine screening required Much higher aeration rates in IFAS zones (up to 3 x) True O&M costs included in present worth analysis favored conventional activated sludge.

18 Nansemond Treatment Plant, HRSD, VA

19 1/1/04 3/1/04 5/1/04 7/1/04 9/1/04 11/1/04 1/1/05 3/1/05 5/1/05 7/1/05 9/1/05 11/1/05 1/1/06 3/1/06 5/1/06 7/1/06 9/1/06 11/1/06 1/1/07 3/1/07 5/1/07 7/1/07 9/1/07 11/1/07 1/1/08 3/1/08 5/1/08 Influent and PE TP (mg/l) TP (mg/l) Challenge: Address Abnormally High P Load and Frequent Bio-P Upsets with BNR Upgrade Parameter Units Influent Average TP mg/l 8.6 BOD/TP Ratio Influent TP Diurnal Sampling 20.0 PE TP 30 per. Mov. Avg. (Influent TP) 30 per. Mov. Avg. (PE TP) Day 1 Influent TP Day 2 Influent TP Day 1 PE TP Day 2 PE TP :00 AM 2:00 am 4:00 am 6:00 am 8:00 AM 9:00 AM 12:00 PM 2:00 PM 4:00 pm 6:00 pm 8:00 pm 10:00 pm Time Sidestream P Load is 30% of Influent Load, and diurnal TP Load is High

20 Challenge: Impact of Dewatering on Effluent TP Centrifuges Running Effluent P Increasing

21 Approach: Upgrade to 5-stage BNR, Implement Ostara for Sidestream Treatment

22 Solution: Struvite Recovery Facility Nansemond TP

23 Concentration mg/l Percent Removal Results: Ortho-P Removal Averaging ~ 90% 1000 Inf and Eff Ortho-P and % Removal for Ostara Influent ortho-p to Ostara Average Eff. ortho-p % ortho-p Removal 7 per. Mov. Avg. (Influent ortho-p to Ostara) 7 per. Mov. Avg. (Average Eff. ortho-p) 7 per. Mov. Avg. (% ortho-p Removal)

24 Concentration mg/l Percent Removal Result: Ammonia Removal Averaging ~ 30% 900 Inf and Eff Ammonia and % Removal for Ostara Influent Ammonia to Ostara Average Eff. Ammonia from Ostara % Ammonia Removal 7 per. Mov. Avg. (Influent Ammonia to Ostara) 7 per. Mov. Avg. (Average Eff. Ammonia from Ostara) 7 per. Mov. Avg. (% Ammonia Removal) *2

25 Lesson Learned: Sidestream Treatment Effective for Achieving Strict Nutrient Limits and Resource Recovery

26 Henrico County WRF, VA

The Challenge: Managing WTP Residuals and Carbon for Optimal/Economic ENR Effleunt TP Concentration, mg/l 4/1/2009 5/1/2009 6/1/2009 7/1/2009 8/1/2009 9/1/2009 10/1/2009 11/1/2009 12/1/2009 1/1/2010

27 The Challenge: Managing WTP Residuals and Carbon for Optimal/Economic ENR Effleunt TP Concentration, mg/l 4/1/2009 5/1/2009 6/1/2009 7/1/2009 8/1/2009 9/1/ /1/ /1/ /1/2009 1/1/2010 2/1/2010 3/1/2010 4/1/2010 5/1/2010 6/1/2010 7/1/2010 8/1/2010 9/1/ /1/ /1/ /1/2010 1/1/2011 2/1/2011 3/1/2011 4/1/2011 5/1/2011 6/1/2011 7/1/2011 Water Treatment Plant Residuals, lb/d 75 MGD plant 5-Stage ENR process The WTP residuals increase BOD capture in the PC and increases the purchased carbon required Parameter 2011 Grant Funding Limits TN (mg/l) 5.0 TP (mg/l) WRF Effluent TP and Water Treatment Plant Residuals 5, , , , , , , , , Water Treatment Plant Residuals lb/d 14 per. Mov. Avg. (Effluent TP Conc.)

28 1/1/2009 2/1/2009 3/1/2009 4/1/2009 5/1/2009 6/1/2009 7/1/2009 8/1/2009 9/1/ /1/ /1/ /1/2009 1/1/2010 2/1/2010 3/1/2010 4/1/2010 5/1/2010 6/1/2010 7/1/2010 8/1/2010 9/1/ /1/ /1/ /1/2010 1/1/2011 2/1/2011 3/1/2011 4/1/2011 5/1/2011 6/1/2011 7/1/2011 PST Onlin and PE cbod/tkn Ratio Approach: Understand How Primary Clarifier Performance Affects Downstream Processes 6 PE cbod/tkn Ratio with Number of PSTs Online PE cbod/tkn PST online 30 per. Mov. Avg. (PE cbod/tkn)

29 Solution: DO Control and # Primary Clarifiers in Service Used to Manage Carbon Costs Excess DO can increase your carbon demand therefore the DO is tapered through the aerobic zones to optimize carbon consumption DO Setpoint 2 mg/l DO Setpoint 1.5 mg/l DO Setpoint 0.5 mg/l

30 4/1/2009 5/1/2009 6/1/2009 7/1/2009 8/1/2009 9/1/ /1/ /1/ /1/2009 1/1/2010 2/1/2010 3/1/2010 4/1/2010 5/1/2010 6/1/2010 7/1/2010 8/1/2010 9/1/ /1/ /1/ /1/2010 1/1/2011 2/1/2011 3/1/2011 4/1/2011 5/1/2011 6/1/2011 7/1/2011 Effleunt TP Concentration, mg/l Centrate TP Concentration, mg/l and Water Plant Residuals lb/d (*10) 1/1/2009 2/1/2009 3/1/2009 4/1/2009 5/1/2009 6/1/2009 7/1/2009 8/1/2009 9/1/ /1/ /1/ /1/2009 1/1/2010 2/1/2010 3/1/2010 4/1/2010 5/1/2010 6/1/2010 7/1/2010 8/1/2010 9/1/ /1/ /1/ /1/2010 1/1/2011 2/1/2011 3/1/2011 4/1/2011 5/1/2011 6/1/2011 7/1/2011 8/1/2011 Carbon Addition (lb COD/d) Effluent TN (mg/l) Results: Lower and More Consistent Effluent TN and TP Supplemental Carbon Addition and Effluent TN 16, , , , , , , , WRF Effluent TP, Centrate TP and Water Treatment Plant Residuals per. Mov. Avg. (Supplemental Carbon lb COD/day) 14 per. Mov. Avg. (Eff TN mg/l) Alum lb/d (*10) 14 per. Mov. Avg. (Effluent TP Conc.) 14 per. Mov. Avg. (Centrate TP Conc.)

31 Lessons Learned: Modifications in Operations Can Have a Significant Impact Utilize process flexibility to adapt to changing influent characteristics Take primary clarifiers on and off line Taper DO in aeration basins Increase NRCY to utilize up front anoxic zones

32 Arlington East WRF, FL Disinfection and Reuse Filters Sludge Holding Tanks Secondary Clarifiers Aeration Basins 1-4 Aeration Basins 5-8 Primary Clarifiers Screens

33 Challenge: Increase Plant Capacity by 25% with No New Basins and Meet TN of 5.6 mg/l Existing 20 mgd secondary treatment facility Project Goals: Plant rerate to 25 mgd AADF Effluent total nitrogen (TN) goal = 5.6 mg/l TMDL based NO NEW BASINS Minimize capital and operating costs No supplemental carbon Existing plant to remain in service Sludge Holding Tanks Aeration Basins 5-8 Disinfection and Reuse Filters Primary Clarifiers Secondary Clarifiers Aeration Basins 1-4 Screens

34 Approach: Model Calibration, Full Scale Pilot, Model Verified and Design Further Optimized Special sampling, BioWin model calibration Full scale test different nitrogen removal configurations determined using model Model further calibrated from pilot, used model to further optimize design

35 Solution: Innovative Hybrid Step Feed Design with Internal Recycle Zone DO Control maximize nitrification, minimize carryover Internal Recycle Pump fully utilize anoxic capacity 4,000 mg/l 3,600 mg/l 40%Q 60%Q Step Feed optimize influent carbon use, wet weather

36 Solution: Modified Aeration Basins *3

37 Conc (mg/l) Results: TN < 4 mg/l, Exceeds the 5.6 mg/l Goal 18 Arlington East WRF - Secondary Effluent Nitrogen &2 online 3&4 online 5&6 online 7&8 online Construction Substantially Complete Monthly Avg TN: June mg/l July mg/l August mg/l September mg/l /18/08 2/26/09 5/7/09 7/16/09 9/24/09 12/3/09 2/11/10 4/22/10 7/1/10 9/9/10 30 per. Mov. Avg. (NO3-N + NO2-N) 30 per. Mov. Avg. (TKN) 30 per. Mov. Avg. (TN)

Lesson Learned: Modeling and Full Scale Testing

innovative and cost effective solution Achieved

6 mg/l with no additional basin volume Estimated

38 Lesson Learned: Modeling and Full Scale Testing Allows Optimization of Existing Infrastructure An innovative and cost effective solution Achieved rerating from 20 to 25 mgd and TN removal to 5.6 mg/l with no additional basin volume Estimated savings versus more conventional approach - $10 million

39 Rivanna WSA Moores Creek WWTP, VA

40 Challenge: Significant Wet Weather Issues in a BNR Upgrade 15-mgd plant with peaks of 37.5 mgd Nutrient removal improvements Upgraded to comply with nutrient limits of TN = 5 mg/l TP=0.3 mg/l Under construction Clarifier failure observed at design peak flow conditions

Impacts of step feed Impacts of polymer Optimization of existing

41 Approach Biowin Coupled with Clarifier 2Dc Model Package Models Individually Calibrated and Verified Specific evaluations Impacts of step feed Impacts of polymer Optimization of existing clarifiers Maintenance of operations Aeration basins and clarifiers OOS

42 MLSS (g/l) SOR (gpd/ft2) Flow (MGD) Approach Wet Weather Modeling Performed Design Storm Hydrograph Elapsed Time (hr) Biowin Predicted MLSS and Flows Input to Clarifier 2Dc Model Step Feed- MLSS Non-Step Feed - MLSS SOR (gpd/ft2) Simulation Time (min)

Feed Alone Greatly Reduced Effluent Solids But

43 Solution Implement Step Feed of Primary Effluent to BNR to Reduce SLR to Clarifiers Sludge Blanket Height ~ 10.5 ft ESS> 150 mg/l No Step Feed Results Step Feed Alone Greatly Reduced Effluent Solids But Modeling shows that clarifier modifications further improve effluent quality

center well Modify density baffles Optimal new clarifier design

44 Results - Integration of Models Supported Critical Design Decisions that Save Money Implement step feed Modify existing clarifiers Enlarge center well Modify density baffles Optimal new clarifier design Enlarged Center Well ESS> 150 mg/l ESS< 15 mg/l Sludge Blanket Height ~ 4.5 ft

Hourly Flow (mgd) Lesson Learned: CFD and BioWin Together Lead to Significant Project Savings June 2006 Storm Event Projected to Design Flow 200 180 Raw INF Grit + PI Channel Prim Clar AX 1 AX 2

45 Hourly Flow (mgd) Lesson Learned: CFD and BioWin Together Lead to Significant Project Savings June 2006 Storm Event Projected to Design Flow Raw INF Grit + PI Channel Prim Clar AX 1 AX 2 Aerobic 1 Aerobic 2 Aerobic 3 Aerobic Filtrate + WWTP Sludge Methanol Post AX Reair RAS Channel ML Channel Alum Alum Tert Sec Clar Effluent TWAS 0 12-Jun Jun Jun Jun Jun Jun Jun Jun-06 Primary Sludge +

46 Summary of Lessons Learned Make the Best Use of Influent Carbon Pilot New Technology if Possible Sidestream Treatment Can Be Effective for Achieving Strict Nutrient Limits and Resource Recovery Modifications in Operations Can Have a Signficant Impact Modeling and Full Scale Testing Allows Optimization of Existing Infrastructure CFD and BioWin Together Lead to Significant Project Savings

47 Questions

Nutrient Removal Optimization at the Fairview WWTP

Alyssa Mayer, PE Principal Engineer Nutrient Removal Optimization at the Fairview WWTP Mark Strahota, PE Associate Presentation Overview Project Background Process Model Development BNR Design Considerations