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OWWA/OMWA Joint Annual Conference May 5 – 8, 2013 Ottawa, Ontario Killaloe Water System, AVIVE TM Water Treatment and Huwa-San Peroxide. Andy K. Valickis, P.Eng. Jim Shubat May 7, 2013. Problem. To find a cost effective solution to reduce the high level of THMs in the Killaloe Water System.
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OWWA/OMWA Joint Annual ConferenceMay 5 – 8, 2013Ottawa, OntarioKillaloe Water System, AVIVETM Water Treatment andHuwa-San Peroxide Andy K. Valickis, P.Eng. Jim Shubat May 7, 2013
Problem To find a cost effective solution to reduce the high level of THMs in the Killaloe Water System
Killaloe Water System • Small system – only 90+ connections • Owned by the Township of Killaloe, Hagarty and Richards • Operated by OCWA • Groundwater wells • GUDI with in-situ filtration • Treatment for iron and manganese removal • UV discharging to clearwells • Long residency time in clearwells and distribution system (3 to 5 days) • THM levels near or over the 100 µg/L limit • Individual samples as high as 140 µg/L
Solution • AVIVETM Water Treatment system from SanEcoTec • Using Huwa-San peroxide (HSP) New form of stabilized peroxide that maintains its residual (equivalent if not better than chlorine) • NSF approved as a residual for drinking water • Used successfully in Europe in drinking water since 2004 • Use HSP for secondary disinfection in the clearwells and distribution system • No chlorine to produce THMs
Advantages of AVIVETM and HSP • Does not breakdown to form THMs or other chlorine based DBPs • Attacks biofilm on pipe walls • Very strong oxidizer • Longer lasting residual • Easy to use for operators • Similar to sodium hypochlorite • No chlorine taste in the drinking water • Significant consumer acceptance
Project Approach • Met with MOE (regulators) • Essential to get their buy-in • Sold the concept to the Township staff and Council • Including our own operations staff • Numerous consultation meetings with MOE Approvals and Health Unit staff • Undertook baseline monitoring and sampling • Public notification
Baseline Monitoring and Sampling • THM formation • Historical THM concentration data available but not where along the process are the majority of the THMs formed • Undertook jar testing to develop a baseline and confirm HSP works • ATP testing of the existing system • Baseline of microbial activity within distribution system • Undertaken over a number of weeks • Other testing • HPC, Total Coliform, E.Coli • Metals testing (copper, lead, iron, manganese) • Residential hot water systems
ATP Testing - Luminultra • Measures Adenosine Triphosphate • A chemical found in living microorganisms • Quantitative indication of microbial activity in a sample • Results in 5 minutes • Indication of the amount of biofilm on pipe walls • Testing equipment loaned to this project by Luminultra • Sampling and testing undertaken by staff from OCWA and Fleming College’s CAWT
System Design • Still need chlorine to achieve CT requirements • Chlorine added to incoming raw well water • Used residency time in contactor tanks and pipes (before UV) to achieve CT • HSP added immediately after UV system • Measure chlorine levels then adjust HSP dosing to quench chlorine + enough to maintain minimum secondary disinfection residual of 3 mg/L • With the quenching of the chlorine, THM formation immediately ceases • Issue of backwashing contactors with “peroxidated” water • Filter to waste until chlorine levels restored
MOE Approvals • Regulatory Relief • Sections from O. Reg. 170/03 under the Safe Drinking Water Act • Amendment to the DWWP • Additional sampling and reporting for initial 3 months • Voluntary sampling (i.e. residential hot water systems)
Equipment • Very similar to what is required for feeding and monitoring sodium hypochlorite • Chemical feed pumps (off the shelf) • Peroxide residual monitors (supplied by Kramer) • Handheld units for sampling in distribution system
Results • HSP system was commissioned and went live in late November 2012 • Immediate THM reduction • Initially down to 25-27 µg/L range • Current levels are in the 20-23 µg/L range • HSP residuals maintained throughout the distribution system • Water quality during the changeover was not affected • HAAs were also significantly reduced • Before 55 to 67 µg/L range; after 8.4 µg/L
THM Reduction Post-HSP
ATP Testing Results Pre-HSP Post-HSP
Residential Hot Water Systems(Microbiological Activity) Pre-HSP Post-HSP Post-HSP
Conclusions • Project a big success! • Significant reduction in the DBPs produced • Proved HSP can retain a disinfecting residual equivalent to or better than chlorine • Significant consumer acceptance of their “new” tap water • We finally have a viable alternative to chlorinating our water supplies