WEF SDC 2011 Expansion of Acton WWTP

1. WEF SDC 2011 Expansion of Acton WWTP University of Guelph Team: Alexandra Chan Adam Erb Cynthia Mason Julia Veerman October 16, 2011

2. Outline • Introduction • Population Analysis • Process Selection • Phase 1 Design • Modeling • Noise & Odour Control • Construction • Phase 2 Design • Economic Evaluation • Conclusions and Recommendations

3. Review of Existing Facility

4. Problem Statement • Current WWTP operating near peak capacity • Need to increase capacity to accommodate projected growth in two phases • Meet projected effluent criteria

5. Design Basis

6. Population Analysis • Predicted linear growth • Assumed water saving devices at 10% • Infiltration/Inflow at 204 L/c/d

7. Process Selection • Constraints • Accommodate design flows • Meet effluent discharge limits • Use available land • Be compatible with existing facility • Criteria • Cost effectiveness • Integration with existing facility • Environmental impact and footprint minimization

8. Phase 1 Design

9. Process Flow

10. Primary Clarifier

11. Primary Clarifier • Add two rectangular clarifiers • New volume 256 m3 • ADF SOR of 27.5 m3/m2/day • Maximum day flow • 62.5% TSS removal • 40.3% BOD removal • Chain & scraper sludge collector and scum removal system

12. Secondary Treatment

13. Aeration System • Two conventional plug flow activated‐sludge system with nitrification • Accommodate 1275 m3/d required • Target MLSS = 4000 mg/L • SRT = 12 days • Fine bubble aeration • Positive displacement blower • Designed for max day flow + additional feedback flow

14. Secondary Clarifier • Two additional secondary clarifiers • Limiting solid flux concept • MLSS = 6620 mg/L • Overflow = 31 m3/m2d • Chain & scraper sludge collector and scum removal system • Max day flow design

15. Tertiary Treatment

16. Chemical Addition • 85 mg/L liquid alum with 45% purity – 824 kg/d • Addition point in activated sludge tank

17. Filtration • Dual media deep bed filtration • Existing filters work well to meet limits • Widely accepted in WWT • Easily retrofit • Leopold™ Type S™ Underdrain • Air scour + surface wash backwash • Max day flow design with one filter out of commission • SLR of 7.2 m3/m2/h http://www.wateronline.com/product.mvc/Universal-Type-S-Underdrain-0002

18. UV Disinfection • UV selected as best disinfection method • Trojan UV3000Plus™ system • LP/HI lamp • Automatic and continuous dose pacing • Automated mechanical/chemical cleaning • Automatic level controller • Sized for peak flow

19. Solids Handling

20. Bio-Solids Digester • Sequential dual-stage digester series • Add new series in parallel • Methane gas collected for heating • Thermophillic Stage 1 • SRT 2 days • Recirculation pump mixing • Mesophillic Stage 2 • SRT 8 days

21. Sludge Drying • Belt press drying after digester • Polymer addition • Increases solids concentration from ~3% to ~25% • Cost-effective in disposal • Reduces footprint

22. Mass Balance

23. System Controls and Instrumentation • Control strategy • Increased control and monitoring • Small relative capital cost • Significant efficiency improvements • Biological treatment • Aeration accounts for up to 50% energy consumption • Matched oxygen demand profile • Intelligent feedback control for aeration, RAS, WAS

24. System Controls and Instrumentation • Clarifiers • Monitoring • Sludge pumping control mechanisms • Digesters • Control for feeding rates, recirculation, heating, withdrawal • Tertiary Treatment • Flow splitting • SCADA • Interfacing with SCADA for remote monitoring

25. Hydraulic Profile

26. Phase 1 – Model Inputs • Projected peak influent concentrations and flows • Proposed plant sizing • Clarifier modeling based on Lessard and Beck dynamic model • Activated sludge modeling completed using the IAWQ1 model

27. Phase 1 – Model Results • BOD and NH3 water quality requirements met • Model Shortcomings: • Chemical phosphorous treatment or tertiary filtration not accounted for

28. Odour and Noise Control • Currently no odour or noise issues • Reduce odour and noise • Buffer zone • Housing potential equipment

29. Construction • Completion in 24 months • Best management practices: • Construct in phases • Protect waterways • Provide training • Conduct inspections

30. Phase 2 Conceptual Design

31. Phase 2 Conceptual Design • Modify Plant B aeration basin configuration to plug flow + BNR • Investigate: • Membrane technology • Phosphorus extraction

32. Phase 1 – Capital Cost Total Capital Cost Estimate = $24M

33. Phase 1 – O&M Cost Annual O&M Cost Estimate = $1.2M

34. Phase 2 – Capital Cost Total Capital Cost Estimate = $12M

35. Conclusions • Expansion design to increase the Acton WWTP capacity • Preliminary Phase 1 design • Additional clarifier, disinfection, and anaerobic digestion trains • CAS + nitrification • Deep bed dual media filter • Belt press • Conceptual Phase 2 design

36. Recommendations • Implement sewer system improvement plan • Conduct more simulations • Obtain more cost-specific information from manufacturers • Conduct pilot tests

37. Acknowledgements Dr. Hongde Zhou, P.Eng., University of Guelph – Faculty Advisor David Arsenault, P.Eng., CH2M Hill – Consulting Advisor Rafiq Qutub, P.Eng., WEAO – SDC Sub-Committee Chair Lauren Zuravnsky, P.E., WEF – Design Competition Sub-Committee Chair