Samuel A. Ledwell *, Environmental Operating Solutions, Inc. sledwell@eosenvironmental.com

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

2. Presentation Outline • 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

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 50,000 • 300 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

6. Neuse River Watershed

7. Permit Details

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: http://lnba.net/missions • Promotes a collaborative effort to go above and beyond permitted requirements

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

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

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

16. Total Nitrogen Removal Performance

17. Total Phosphorus Removal Performance

18. Performance Summary Eliminating the sodium aluminate feed saved the facility approximately $175/day

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 TESTS • 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.

21. PHOSPHORUS UPTAKE/RELEASE REACTORS

22. Phosphorus Release/Uptake Test Results CARBON DOSE CARBON DOSE ANAEROBIC AEROBIC

23. Phosphorus Release and Uptake Rates 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-Q3 2013 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