1. OBG PRESENTS: Lead Corrosion: Lessons Learned and New Approaches George Rest, PE | Michelle McEntire, PE – Tifft Water Supply Symposium – September 22, 2016

2. AGENDA Basics of Lead in Drinking Water Reasons Behind Lead Non-Compliance Questions 2

3. 3 BASICS OF LEAD IN DRINKING WATER

4. Sources and Contributors to Lead 4 Faucet aerator Galvanized piping Lead service lines Old fixtures (kitchen faucets, water fountains) and lead solder Kitchen faucet aerators (routinely clean) Brass installed prior to 2014 (EPA Lead- Free Act reduced allowable lead in brass from 8% to 0.25%) Galvanized iron service lines Galvanized iron pipe in home plumbing

5. Adjust the water chemistry to produce stable water quality conditions that inhibit lead release Remove service lines and plumbing materials that contain lead  pH and alkalinity adjustment  Corrosion inhibitor (typically orthophosphate) Traditional Lead Compliance Strategies 5

6. Lessoned Learned and Observations from OBG Projects and Recent Research 6 Lead compliance challenges are often the result of particulate lead Recent research and our experience draws a strong correlation between particulate iron and particulate lead A holistic approach requires addressing: Classical lead solubility: pH, DIC (carbonate alkalinity), buffering capacity Particulate iron: From unlined cast iron water mains and galvanized piping Biological activity in distribution mains: Both an indicator and potential cause of water quality problems Corrosion inhibitors: Orthophosphate can control dissolved and particulate lead

7. Optimization of Soluble Lead 7 Source: Abigail Cantor, 2014 WQTC, “Theoretical Lead and Copper Release Into Drinking Water Versus Reality” Waters With Higher DIC Found More Stable

8. Lessoned Learned and Observations from OBG Projects and Recent Research 8 Lead compliance challenges are usually the result of particulate lead Recent research and our experience draws a strong correlation between particulate iron and particulate lead A holistic approach requires addressing: Classical lead solubility: pH, DIC (alkalinity), buffering capacity Particulate iron: From unlined cast iron water mains and galvanized piping Biological activity in distribution mains: Both an indicator and potential cause of water quality problems Corrosion inhibitors: Orthophosphate can control dissolved and particulate lead

9. Water System Schematic – Source to Tap 9 Source: Sheldon Masters and Marc Edwards - WQTC 2013 Correlation Between Particulate Iron and Particulate Lead Iron from galvanized pipe and fittings

10. 230%> 54%> Synthetic WaterSynthetic Water with Iron Water System Schematic – Source to Tap 10 Correlation Between Iron and Lead Source: Sheldon Masters and Marc Edwards - WQTC 2013

11. Lead Profiles 11 Iron and lead levels have similar trend Studies conducted in homes

12. Lessoned Learned and Observations from OBG Projects and Recent Research 12 Lead compliance challenges are usually the result of particulate lead Recent research and our experience draws a strong correlation between particulate iron and particulate lead A holistic approach requires addressing: Classical lead solubility: pH, DIC (alkalinity), buffering capacity Particulate iron: From unlined cast iron water mains and galvanized piping Biological activity in distribution mains: Both an indicator and potential cause of water quality problems Corrosion inhibitors: Orthophosphate can control dissolved and particulate lead

13. Benefits of Chlorine Residual 13 Source: WRF Proj. #4409 Chlorine residual also supports formation of hard scale in lead service lines

14. Impacts of Biofilms 14

15. Lessoned Learned and Observations from OBG Projects and Recent Research 15 Lead compliance challenges are usually the result of particulate lead Recent research and our experience draws a strong correlation between particulate iron and particulate lead A holistic approach requires addressing: Classical lead solubility: pH, DIC (alkalinity), buffering capacity Particulate iron: From unlined cast iron water mains and galvanized piping Biological activity in distribution mains: Both an indicator and potential cause of water quality problems Corrosion inhibitors: Orthophosphate can control dissolved and particulate lead

16. DC Water – Impact of Using Orthophosphates 16 Orthophosphates were introduced in 2004 for corrosion control Immediate reduction in the lead level Continued improvement since 2004

17. A Holistic Approach is Required For Reliable Lead Control 17 Maintain a chlorine residual to minimize biofilms and promote a strong lead scale Optimize DIC (alkalinity) to promote stable distribution system water quality Flush effectively to remove biofilms and loose iron deposits Phosphates are a widely used and effective:  Secondary barrier  Effective for iron and lead  Improves chlorine residual  Ongoing research on use at high pH

18. 18 THE REASONS BEHIND LEAD NON-COMPLIANCE

19. Why Utilities Exceed the Lead Action Level 19 Unintended Consequences Flint, MI Desire to save $: changed source and did not feed corrosion control agent DC Water Increased chlorine to address coliform, then changed disinfectant to lower DBPs Providence Change in corrosion control strategy to reduce lead unleashed iron VA Utility Changed coagulant to lower DBPs caused high chloride/sulfate mass ratio NYS Utility Without any lead services; Added new source for growth, changing water chemistry

20. 20 Flint, MI Combination of lead and iron pipes in distribution system Detroit Water & Sewerage Department  Phosphate corrosion inhibitor used  Mineral passivation layer on pipe wall Flint River  No corrosion inhibitor used -> passivation layer dissolves  Low pH  High chloride levels

21. Why Utilities Exceed the Lead Action Level 21 Unintended Consequences Flint, MI Desire to save $: changed source and did not feed corrosion control agent DC Water Increased chlorine to address coliform, then changed disinfectant to lower DBPs Providence Change in corrosion control strategy to reduce lead unleashed iron VA Utility Changed coagulant to lower DBPs caused high chloride/sulfate mass ratio NYS Utility Without any lead services; Added new source for growth, changing water chemistry

22. 22  Free chlorine was increased from 2.2 to 3.2 mg/L  Lead scale formed - Pb (IV) species Mid 1990s  pH fluctuated from 7 to 8.9  pH of 7 - not optimal for corrosion control 1992 – 2004  Converted from free chlorine to chloramines  Lead scale changed - Pb (IV) to Pb (II) species  Increase in lead released from lead service lines 2000 DC Water

23. Why Utilities Exceed the Lead Action Level 23 Unintended Consequences Flint, MI Desire to save $: changed source and did not feed corrosion control agent DC Water Increased chlorine to address coliform, then changed disinfectant to lower DBPs Providence Change in corrosion control strategy to reduce lead unleashed iron VA Utility Changed coagulant to lower DBPs caused high chloride/sulfate mass ratio NYS Utility Without any lead services; Added new source for growth, changing water chemistry

24. Providence History of Lead Compliance (1997 – 2005) 1996 – Treatment Optimization at pH >10 Lead Action Level = 15 ppbLCR Compliance Samples = 90 th percentile

25. pH versus Theoretical Lead Solubility

26. pH Adjustment to 9.7; Release of Particulate Iron and Lead November 2005 Adjustment to pH ~ 9.7 Lead Action Level = 15 ppb LCR Compliance Samples = 90 th percentile 2006 - Action Level exceeded

27. Holistic Approach Has Brought PW Back Under Action Level November 2005 Adjustment to pH ~ 9.7 Lead Action Level = 15 ppb LCR Compliance Samples = 90 th percentile 2006 - Action Level exceeded March 2013 Adjustment to pH ~ 10.2

28. Why Utilities Exceed the Lead Action Level 28 Unintended Consequences Flint, MI Desire to save $: changed source and did not feed corrosion control agent DC Water Increased chlorine to address coliform, then changed disinfectant to lower DBPs Providence Change in corrosion control strategy to reduce lead unleashed iron VA Utility Changed coagulant to lower DBPs caused high chloride/sulfate mass ratio NYS Utility Without any lead services; Added new source for growth, changing water chemistry

29. Why Utilities Exceed the Lead Action Level 29 Unintended Consequences Flint, MI Desire to save $: changed source and did not feed corrosion control agent DC Water Increased chlorine to address coliform, then changed disinfectant to lower DBPs Providence Change in corrosion control strategy to reduce lead unleashed iron VA Utility Changed coagulant to lower DBPs caused high chloride/sulfate mass ratio NYS Utility Without any lead services; Added new source for growth, changing water chemistry

30. Acknowledgements 30 Abigail Cantor Consultant Marc Edwards, PhD Virginia Tech Michael Schock USEPA Office of Research & Development Providence Water DC Water

31. OBG PRESENTS: OBG | THERE’S A WAY Questions? George.Rest@obg.com - (301) 731-1162 | Michelle.McEntire@obg.com - (585) 295-7713