1. Buckhorn Disinfection Byproducts / Backwash Disposal Project Board of Directors Meeting June 14, 2012

2.  Project Purpose and Issues  Backwash Management Strategies  DBP Reduction Alts and Recommendations  Recommended Phasing Plan Presentation Outline

3.  Project Purpose:  Assure Compliance with Stage 2 Disinfection Byproduct (DBP) Rule (a) & Develop An Integrated Backwash Management Strategy  Key Project Issues:  Elevated DBPs in the Buckhorn WTP Distribution System  Insufficient Pond 7 Storage Capacity for Backwash Waste Water Disposal Project Purpose and Issues (a) Effective October 1, 2013.

4. 1.Expand Pond 7 to Contain 100-Yr Storm Event per WDR 2.Remove Solids at WTP to allow Recycle to WTP and/or Discharge Treated Backwash Water (BWW) to Pond 7 a)No WDR Required 3.Select Best Long-Term and Most Cost Effective Backwash Water Management Strategy Backwash Water Management Strategies for the Buckhorn WTP

5. Comparison of Solids Removal Alternatives Alternative Comparison Criteria (Score 1 to 5, 5 = best) Score Regulatory Construction Cost Applicability ParticulateChemical ComplianceRemovalCompatibility 1. Bag Filter w / Recycle3 5 ($255k)11515 2. Bag Filter w / Discharge2 1 ($760k – $910k)31512 3. Mech. Dewatering w / Recycle3 3 ($525k)1119 4. Mechanical Dewatering w / Discharge2 2 ($660k)11511 5. Conventional Drying Beds3 1 ($1,525k)354 16 (site constraints) 6. Proprietary Drying Beds5 4 ($355k)55423 7. Reuse Old Plant (Conv. Drying Beds)3 1 ($1,515k)25415 8. Leachfields1 5 ($200k)15517 9. Micro Screen3 2 ($595k – $900k)23515 10. Expand Pond4 3 ($500k - $650k)35520

6. Proposed Flow Schematic

7. Potential Site Layout Recommended Deskins TM System (Solids Removal and Dewatering)

8. Stage 2 DBR Rule Compliance Historical TTHM/HAA5 Results

9.  TOC Removal  Coagulation/Filtration  Adsorption  Oxidation  Reduce Chlorine Dose  Maintain Disinfection CT  Maintain Residual Disinfectant throughout System  Distribution System Modifications  Reduce Water Age  Tank Materials DBP Removal Strategies

10. Buckhorn WTP Distribution System DBP Sample Location

11. Comparison of DBP Reduction Alternatives DBP Reduction Alternative Capital Cost (1-5, 5 = Lowest) Operating Cost (1-5, 5 = Lowest) DBP Reduction (1-5, 5 = Greatest) Complexity (1-5, 5 = Simplest) Total Score TOC REMOVAL Chlorine Dioxide 2 ($180,000) 1 ($30,000/yr) 33 10 ACH 4 ($25,000) 3 ($20,000/yr) 45 16 Ferric Chloride 3 ($45,000) 2 ($25,000/yr) 33 11 REDUCE CHLORINE RESIDUAL Clearwell Baffling/ Chlorine Booster Stations 1 ($160,000) 3 ($20,000/yr) 52 10 pH Adjustment Location 4 ($20,000) 5 ($0/yr) 35 17 Reduce CT Provided 5 ($0) 5 ($0/yr) 35 18 DISTRIBUTION SYSTEM MODIFICATIONS Tank Mixing 3 ($175,000) 5 ($0/yr) 24 14

12. ACH DBP Reduction

13. Recommended Phasing Plan Goal: ACH feed system operational Summer 2013; highest DBP concentrations have historically occurred during summer season a Step / ActivityEst. Construction Cost ($) 20122013 JJASONDJFMAM 1. Solids Removal Project355,000 DesignBConstruct & Startup 2. Full Scale Testing to Minimize Chlorine Dose 0b0b 3. Tank A Modifications50,000 DBConstruct 4. ACH Improvements25,000 DBC & SU Total Est. Construct Cost430,000 a First set of Stage 2 DBP compliance testing to be conducted prior to October 1, 2013 b Testing conducted by Agency operators and staff

14. Questions ?