1. Municipal Wastewater Efficiency Improvements Potential Savings for the 6 th Power Plan September 30, 2008 Regional Technical Forum South Treatment Plant - Renton,Washington

2. Municipal Wastewater Industry in the PNW Over 800 Plants use 175 aMW of Energy Processes Include – Collection – Treatment Sludge Processing & Disposal – Discharge Picture from: Arkansas Watershed Advisory Group

3. The Many Factors that Affect Plant Energy Consumption Influent Biological Oxygen Demand (BOD) Effluent BOD Weather/Location MGD design capacity MGD flow Primary Clarifier Effectiveness Secondary Treatment Process Type – Activated Sludge Coarse or fine bubble aeration Dissolved Oxygen control method – Aerated Lagoon Dispersed Aeration or Mechanical Aeration Varying amounts of aeration – Trickle Filter – Disinfection method (Chlorine or UV) Tertiary Treatment Process Type Sludge Treatment Processes – Dewatering method – Digestion Onsite Generation (IC Engine or Micro-Turbine Using Digester Gas, Micro-Hydro at discharge, etc.) Lebanon, OR

4. Energy Savings Measures – VFDs – Upgrade to premium efficiency motors – Aeration blower control via automated dissolved oxygen monitoring – Fine bubble diffusers – Optimize pumping and blower configurations and operation/controls – Upgrade to more efficient pumps and blowers – Use hydraulic digester mixing & optimize mixing time – Lighting DO Control from wateronline.com Blower from spenserturbine.com Fine Bubble Diffusters from sequencertech.com

5. 5 th Power Plan Summary Technical Potential Retrofit Measures = 50.5 aMW New Construction = 14.5 aMW 65.0 aMW Plan called for a total of 37 aMW of energy savings at 1.4 cents/kWh. Achievements since 5 th Plan Energy Trust of Oregon: – 23 Projects – Savings = 1.5 aMW – Measure Cost = $10 million

6. Update for 6 th Plan: Data Sources

7. Proposed Changes to Savings

8. More on Savings Change large activated sludge plant baseline consumption because: Change % savings available to medium activated sludge plants because:

9. Proposed Changes to Cost & Benefits 5 th Plan Assumptions: Measure Cost: – $20k to $200k depending on size (or about $0.10/kWh) O&M Costs: – $500/mo service agreement Non Energy Benefits: – $34k/year per facility for reduced manual DO sampling – $5/day for reduced polymer purchased in AS systems – $10k-25k/MGD for reduction in solids

10. Summary – 6 th Plan Proposal New Construction Savings – Projected Additional Capacity: 288 MGD – Projected Additional Load: 20 aMW – Technical Potential: 3.3 aMW Retrofit Savings – Technical Potential: 27.5 aMW