1. Constraints and Threats - are They Leading Us to Opportunities? BACWA Biosolids Workshop June 2, 2008 Perry Schafer, PE, BCEE, Brown and Caldwell BACWA Biosolids Workshop June 2, 2008 Perry Schafer, PE, BCEE, Brown and Caldwell Bay Area Clean Water Agencies

2. Constraints/threats are having an impact  Adverse public perception (land application, etc.)  Energy price increases  Landfilling limits  Regulatory controls  Biosolids cost escalation and uncertainty  Adverse public perception (land application, etc.)  Energy price increases  Landfilling limits  Regulatory controls  Biosolids cost escalation and uncertainty

3. Price for Class B/A cake trucking and use/disposal 100 80 60 40 20 0 100 80 60 40 20 0 $ / Wet Ton California Price Range Year 2010200520001995199019851980

4. Calif. Agencies have/are responding to change  Preference for non-land-application disposition  Improved dewatering and drying systems  More efficient digestion, and boosting biogas production  RFPs and contracts for privatized/merchant facilities  Research and demonstration projects (muni and private)  Preference for non-land-application disposition  Improved dewatering and drying systems  More efficient digestion, and boosting biogas production  RFPs and contracts for privatized/merchant facilities  Research and demonstration projects (muni and private)

5. Rough cost comparison (2008 time frame) Class B Truck/ Land Ap Open Compost Closed Compost Heat Dry Alkaline Treat. Air Dry Lagoon/ Air Dry Class A Digest. $/wet ton (digested-dewatered) 150 100 0 50 Costs for digestion and dewatering not included. Class A w/o Dewatering Note: Assumes ~25% cake solids as basis.

6. Sewage sludge disposal in the EC and Germany (from Robert Schmidt, City of Munich, Germany, 2008)

7. Where is EC/Germany headed?  Traditional land application greatly constrained  Landfill almost eliminated  Incineration and energy recovery continue/expand  Co-firing with coal or biowaste in power plants  Use in cement kilns  Drying (solar, waste heat)  Greater digestion efficiency  GHG and renewable energy – prime issues  Traditional land application greatly constrained  Landfill almost eliminated  Incineration and energy recovery continue/expand  Co-firing with coal or biowaste in power plants  Use in cement kilns  Drying (solar, waste heat)  Greater digestion efficiency  GHG and renewable energy – prime issues

8. Summary – Key Take-aways  Maximize digestion efficiency  Assess low-energy methods for volume reduction  Consider biosolids products for energy use  GHG and energy issues becoming much more important  Maximize digestion efficiency  Assess low-energy methods for volume reduction  Consider biosolids products for energy use  GHG and energy issues becoming much more important