Co-Generation: Today’s Reality Larry McFall Plant Operations Manager Rock River Water Reclamation District Rockford, IL

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

Water Treatment Primary –Screening, Grit, & Primary Clarification Aerobic Activated Sludge –Final Clarification Disinfection

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

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)

Treatment & Utilization Process Anaerobic Digestion –Controlled Conditions –Utilize Waste Heat from Electrical Generators Condition Biogas –Remove Moisture –Remove Contaminants Electrical Generators –Produce Electricity –Recover Waste Heat

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

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

Anaerobic Digestion

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

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

Biogas Siloxane + Oxygen  Silicone Dioxide (Sand)

Biogas Siloxanes as Si, mg/M 3 –Maximum 46.6 –Minimum 2.7 –Average 13.4 –Major Constituent D5 (Decamethylcyclopentasiloxane)

Biogas

Generators 3 1 MW each Fuel –Biogas –Natural Gas Heat Recovery –Jacket Water –Exhaust Gases

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

Add Generator Picture

Investment Capital –$2,000 per kW of Electricity Operation & Maintenance –$0.01 per kWhr

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

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

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

Co-Generation: Today’s Reality Questions?

Co-Generation: Today’s Reality Larry McFall Plant Operations Manager Rock River Water Reclamation District Rockford, IL