UV Disinfection for Unfiltered Surface Water Regulatory Compliance

1. UV Disinfection for Unfiltered Surface Water Regulatory Compliance Kevin Castro, PE | GHD Image placeholder Image placeholder Image placeholder

2. UV Disinfection for Unfiltered Surface Water Regulatory Compliance Kevin Castro, PE | GHD

3. Presentation outline • Background • Regulatory Requirements • Water Quality • Basis of Design • Procurement/Construction • Benefits/Results • Lessons Learned • Questions Image place holder Image place holder Image place holder

4. Village of Skaneateles, New York • Village demands • 0.6 mgd average daily demand • 1.2 mgd maximum daily demand • 2.0 mgd pump capacity • Served off City of Syracuse Skaneateles Lake supply • FAD since 1991 • 3 log giardia inactivation through chlorination (using City of Syracuse chlorination) • Population served ± 3,000

5. Skaneateles/Syracuse water supply system

6. Regulatory requirements • SWTR • 1991 FAD • 3 log giardia inactivation through chlorination • 4 log virus inactivation through chlorination • Contact tank and contact transmission main constructed 1995 • LT2ESWTR • 2 or 3 log cryptosporidium inactivation • Two barriers: UV/Cl2

7. Water quality • Turbidity • Average = 0.8 NTU • Range = 0.5 to 10 NTU • Syracuse intake shutdowns control turbidity • UVT • Average = 97% • Minimum value = 92% • ICR = 96 to 98% • Limited historical data • Design Range = 90 to 98% • Cryptosporidium • 1 oocyst detected since 1986 • 2 log cryptospordium inactivation required • Fouling Potential - Low Image place holder Image place holder Image place holder

8. Basis of design • 2 log cryptospuridium inactivation = 5.8 mJ/cm2 • 3 log giardia inactivation = 11 mJ/cm2 • Designed for 3 log giardia inactivation • UVT – 90% minimum • 95% average • Turbidity < 10 NTU • Lamp Technology – Medium Pressure or LPHO • Two 100% redundant UV reactors

9. Basis of design (cont’d) • Max flow = 2 mgd • Ave flow = 1 mgd • Min flow = 0.5 mgd • Reduce giardia chlorine contact time requirements • Max headloss – 7 inches • Improved monitoring (UVT, Turbidity, Cl2)

10. Procurement • Preselection vs. pre-purchase • Preselection approach chosen to give contractor ultimate responsibility for system performance. • Life cycle cost bid • Equipment costs • Lamp/ballast costs • Power costs

11. Procurement • Procurement results • Trojan awarded selection

12. Construction • Space available with BPS • Pump replacement * • VFDs provided * • Reduce pump flow to 1 mgd (90% speed) • Reduce pump energy cost by $4,000/year • Reduce pump starts to < 4/day • Eliminate cavitation of pumps on low lake level • SCADA for monitoring/control/reporting • *Provided through ARRA grant Image place holder Image place holder Image place holder

13. Construction UV Controls UV Disinfection

14. Construction Image place holder SCADA Pumps

15. Construction Image place holder Turbidity/Chlorine/UVT Monitoring Chlorine Booster System& Monitoring

16. Results/benefits • 2 log cryptosporidium inactivation – compliance • 3 log giardia inactivation through UV/Cl2 • 4 log virus inactivation through Cl2 • Use transmission main and contact tank for improved fire protection (currently under development) • Reduced pump starts to < 4/day • Reduced energy/cost for pumping • Improved monitoring/reporting of CT, turbidity, Cl2 residual • < 0.1% off-spec water since March 2012

17. Lessons learned • Validation layout ≠ Approved layout • Alarm management during maintenance • Nuisance alarms during lamp and UVT transmitter maintenance • Preselection was effective procurement approach • Avoid pre-preselection design layouts ($$) • Define distances for power/instrumentation cabling • LT2ESWTR allows off-spec water

18. Questions? • Please contact Kevin Castro at kevin.castro@ghd.com

19. www.ghd.com