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Samuel A. Ledwell*, Environmental Operating Solutions, Inc. Jimmy Pridgen, City of Wilson Water Reclamation Facility Nicholas.

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Presentation on theme: "Samuel A. Ledwell*, Environmental Operating Solutions, Inc. Jimmy Pridgen, City of Wilson Water Reclamation Facility Nicholas."— Presentation transcript:

1 Samuel A. Ledwell*, Environmental Operating Solutions, Inc. Jimmy Pridgen, City of Wilson Water Reclamation Facility Nicholas Eatmon, City of Wilson Water Reclamation Facility Rodney Harris, City of Wilson Water Reclamation Facility NOVEMBER 11 TH 2013 CITY OF WILSON WRF – ACHIEVEMENTS IN TOTAL NITROGEN AND PHOSHPORUS REDUCTION BELOW ENR LEVELS

2 City of Wilson - Background Wilson-Hominy Creek WRF – Upgrade history, plant configuration Total Nitrogen and Total Phosphorus Goals Influent Characteristics Transition from Methanol to MicroC 3000 Performance Comparison – Total Nitrogen – Total Phosphorus Phosphorus Release/Uptake Tests Conclusion and Discussion Presentation Outline

3 Acknowledgements City of Wilson Team: Jimmy Pridgen – Water Reclamation Manager Barry Parks – Director of Water Resources Nick Eatmon – Lead Operator Debra Collins – Chemist/Laboratory Supervisor Rodney Harris – Operations and Maintenance Supervisor

4 Plant Vitals 14 MGD Design Capacity 20,000 metered customers Population of 50, miles of collection system with 20 lift stations Flow from Black Creek, Lucama and Sims Discharge to Contentnea Creek – sub basin of Neuse River

5 Upgrade and Capital Improvement History 1958 Original Plant Constructed1974 Upgrade to 10 MGD Updated headworks Two additional primaries and two additional anaerobic digesters Activated Sludge Basins #1-3 Centrifuge 1992 Modifications Trickling filter converted to BPR tank Centrifuge removed – GBT added 1998 Upgrade to 14 MGD Converted activated sludge basins to BNR basins. Added three additional BNR basins Methanol feed system, sodium hypochlorite & sodium bisulfite feed systems added Added tertiary denitrification filters 2004 Upgrade of Dewatering Systems New GBT’s and BFP’s and gas drying system New administration building BNR basin #7 added 2012 Upgrade of Influent Pump Station

6 Neuse River Watershed

7 Permit Details ParamterLimitDetail Ammonia1.0/3.0Monthly/Weekly BOD55.0/7.5Monthly/Weekly Total Phosphorus2.00Quarterly TSS30/45Monthly/Weekly Total Nitrogen157,886 lbs3.7 mg/L at Design

8 Neuse River Sustainability and Responsibility Neuse River Compliance Association (NRCA) Lower Neuse Basin Association (LNBA) 21 Members of NRCA Mission to “preserve water quality in the Neuse River and more specifically promote and achieve compliance with Total Maximum Daily Load (“TMDL”) requirements for total nitrogen (“TN”) at the Neuse River Estuary” – Source: Promotes a collaborative effort to go above and beyond permitted requirements

9 Flow Schematic PC SC ANA Dgstr Biotrain Cent rate BPR 75% RAS 25% RAS GBT WAS Filtrate Thickened WAS BFP Filtrate Cake Filters Hypo & Re-air Carbon Source

10 Wilson – Satellite View

11 Solids Processing GBT typically operates Monday to Friday BFP typically operates Tuesday to Friday Filtrate from both processes enters a centrate holding tank that feeds centrate to the headworks Centrate has a significant impact on TN and TP loading

12 Influent Characteristics MethanolMicroC 3000 PeriodJan'12 - Oct'12Nov'12-Sep'13 Flow Temperature BOD TKN3130 TN Load BOD:TKN Total Phosphorus TP Load BOD:TP SRT

13 Methanol Storage and Feed System 10,000 gallon storage tank with spill containment 4 LMI Diaphragm Pumps Originally, single line charged all 7 biotrains Re-plumbed with rotameters to balance the methanol feed to each second anoxic zone One LMI pump is dedicated to feed methanol to denitrification filters Methanol not fed to filters due to high DO, low NOX-N concentration

14 Carbon Source Transition Conversion from methanol to MicroC 3000 occurred mid October 2012 No modifications to storage and feed equipment were made No disruption in TN removal performance Initially feed rate was set at 10% higher compared to the historical methanol feed rate Methanol October 11, 2012

15 Carbon Source Comparison MicroC 3000Methanol Specific Gravity pH11~ 7 FlammabilityFlammable COD kg/L Methanol66%100% Ethanol10%0% Propanols9%0% Butanols3%0% Water14%0% Price/lb N removed90%100%

16 Total Nitrogen Removal Performance

17 Total Phosphorus Removal Performance

18 Performance Summary Eliminating the sodium aluminate feed saved the facility approximately $175/day UnitsMethanolMicroC 3000 Final Effluent TNmg/L TN % Removed93.1%93.2% Final Effluent TPmg/L TP % Removed85.4%95.2% Feed Rategpd % Sodium Aluminate Feedlbs/day1000Discontinued

19 MicroC 3000 Contributing to EBPR? MicroC 3000 contains C3 and C4 alcohols such as isopropanol and butanols. Could these alcohols be fermented or otherwise used for formation of PHB and Phosphorus release? We know that glycerol (a C3 polyol) supports EBPR……

20 Phosphorus Release/Uptake Rate (PUR) tests were performed on mixed liquor from the plant using a method proposed by Wachtmeister (1997). Upon arrival and in between tests, sludge is aerated to eliminate all soluble COD Reactors were run in Anaerobic/Aerobic modes. Tests were repeated on Day 2. One reactor fed with MicroC 2000™. Methanol was used as a control. PHOSPHORUS RELEASE/UPTAKE TESTS Anaerobic PhaseAerobic Phase Duration240 min90 min Sampling Interval20 min15 min AnalysisTemperature, pH, DO, ORP, NO3-N, NO2-N, PO4-P, TP, TSS/VSS Reactor Conditions 20°C Low RPM mixer pH control to 7 Sparge with nitrogen gas Ca and K in excess Aerobic: Compressed air sparge; DO near saturation ATU to inhibit nitrification Electron Donor Dose50 mg COD/g VSSNo electron donor feed

21 PHOSPHORUS UPTAKE/RELEASE REACTORS

22 Phosphorus Release/Uptake Test Results ANAEROBIC AEROBIC CARBON DOSE

23 Phosphorus Release and Uptake Rates MethanolMicroC 3000 Release mg P/g VSS/hr Uptake mg P/g VSS/ hr Release mg P/g VSS/hr Uptake mg P/g VSS/ hr Test Test Phosphorus release and uptake rates are generally higher for MicroC 3000 but overall the rates are very low and net phosphorus release and uptake are low. Second dose of carbon resulted in further release in phosphorus with MicroC 3000 but not with methanol indicating that if higher weight alcohols are to be used by PAO’s, the ORP must be very low

24 TP Mass Balance % TP in BFP cake since eliminating sodium aluminate feed – 4.05% (6.78% for VS) If true, indicates a PAO enriched biomass

25 TP Discussion and Conclusions TP Mass Balance indicates PAO enrichment RAS TP indicates PAO enrichment BOD:TP is favorable for EBPR process (35-40:1) Primary clarifier effluent Ortho-P is identical for the two periods (4.71 mg/L). Secondary clarifier effluent Ortho-P is 0.99 and 0.40 for the methanol and MicroC periods respectively Metal Salt Eliminated Improved final effluent TP performance is a result of EBPR Bench scale tests did not show with absolute certainty that the higher alcohols in MicroC 3000 are influencing performance However, we believe MicroC 3000 is playing a role

26 Final Thoughts Transition from methanol to MicroC 3000 was seamless Reduced TN from 2.15 to 2.00 mg/L Reduced TP from 0.83 to 0.21 mg/L Q1-Q savings on chemical costs is approximately $68,000 Performance achieved without metal salt addition and without tertiary denitrification filters

27 Lessons Learned and Beneficial Modifications Addition of VFD’s on influent pump station resulted in a reduction of 5-10% in TN (prior to this study) Modification of methanol distribution lines resulted in better flow splitting of methanol to the 7 Biotrains Recognizing the impact of solids processing side streams on TN and TP load is important

28 Future Goals Close the mass balance on phosphorus Automate carbon feed based on flow or nitrate analyzers Install Turbo Blowers with VFD’s to better control airflow to basins Equalize dewatering filtrate to constant feed over 24 hours or flow pace Feed carbon to the BPR tank to enhance and/or stabilize the EBPR process

29 Thank you & Questions The final product


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