Co-Generation: Today’s Reality

1. Co-Generation: Today’s Reality Larry McFall Plant Operations Manager Rock River Water Reclamation District Rockford, IL lmcfall@rrwrd.dst.il.us

2. Introduction • 1,100 Miles of Sewer • 33.9 MGD Influent • 7 Communities • 75,000 Accounts • 240,000 Connected Population

3. Water Treatment • Primary • Screening, Grit, & Primary Clarification • Aerobic Activated Sludge • Final Clarification • Disinfection

4. Energy Introduction • Raw Materials • Waste Organic Material in Wastewater (Feedstock) • Treatment & Utilization Process • Anaerobic Digester • Electrical Generators • Products • Electricity • Heat • Biosolids (Fertilizer)

5. Waste Organic Feedstock • Waste Organic Material in Wastewater • Raw Sludge • Primary Clarifiers • Gravity Thickener (5.4% Solids) • Waste Activated Sludge • Gravity Belt Thickener (6.6% Solids) • Skimmed Fats, Oils & Grease (FOG)

6. Treatment & UtilizationProcess • Anaerobic Digestion • Controlled Conditions • Utilize Waste Heat from Electrical Generators • Condition Biogas • Remove Moisture • Remove Contaminants • Electrical Generators • Produce Electricity • Recover Waste Heat

7. Anaerobic Digestion • Controlled Conditions • Mesophilic Digestion (100º F or 38º C) • Complete Mix • Biological Process • Acid Formers • Methanogenic Bacteria

8. Anaerobic Digestion • Biogas • Methane, Carbon Dioxide, Nitrogen • Water Vapor • Hydrogen Sulfide, Siloxanes, Hydrogen • Biosolids • Fixed & Stabilized Organic Solids • Nutrients & Micro Nutrients

9. Anaerobic Digestion

11. Biogas • Biogas Conditioning • 1st Stage Hydrogen Sulfide Removal • Ferric Chloride Addition to Digesters • 1st Stage Moisture Removal • Refrigeration to 45º F Dewpoint • 2nd Stage Moisture Removal • Refrigeration to 34º F Dewpoint • Coalescing Filter

12. Biogas • Biogas Conditioning Continued • Pressure Boost • Mixed Carbon Bed • Siloxane Removal • 2nd Stage Hydrogen Sulfide Removal • Reheat Gas

13. Biogas Siloxane + Oxygen  Silicone Dioxide (Sand)

16. Biogas • Siloxanes as Si, mg/M3 • Maximum 46.6 • Minimum 2.7 • Average 13.4 • Major Constituent • D5 (Decamethylcyclopentasiloxane)

17. Biogas

18. Generators • 3 Generators @ 1 MW each • Fuel • Biogas • Natural Gas • Heat Recovery • Jacket Water • Exhaust Gases

19. Generators • Operation and Maintenance • Laboratory • Gas Analysis • Engine Oil Analysis • Routine Maintenance • Change Oil and Filters • Gap or Change Spark Plugs • Rectifiers

20. Add Generator Picture

21. Investment • Capital • $2,000 per kW of Electricity • Operation & Maintenance • $0.01 per kWhr

22. Bio-Products • Electricity • 410 MWhr/Month • $33,000/Month • Heat • 4.5 Million BTU/hr each Engine • Process Heat for Digesters • Building Heat

23. Bio-Products • Biosolids (Fertilizer) • Apply 17,000 wet Tons Annually • 1,700 Acres of Farmland Annually • Corn • Wheat • Soybeans • Fertilizer Value of $85/acre

24. Future Improvements • Co-Digestion of High Strength Wastes • Fats, Grease and Oils Direct from Source • Bio-diesel Byproducts • Algae • High Strength Food Production Wastes • Utilization of Waste Heat • Cooling

25. Co-Generation: Today’s Reality Questions?

26. Co-Generation: Today’s Reality Larry McFall Plant Operations Manager Rock River Water Reclamation District Rockford, IL lmcfall@rrwrd.dst.il.us