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Corrosion Control in a Small Water Systems with Lead Service Lines: A Case Study
Citation:
Lytle, D., M. Schock, AND C. Formal. Corrosion Control in a Small Water Systems with Lead Service Lines: A Case Study. AWWA ACE Annual Conference, Las Vegas, NV, June 11 - 14, 2018.
Impact/Purpose:
Presentation on lead to be given at the AWWA ACE Annual Conference in Las Vegas. Corrosion Control Treatment: Prior 2010, caustic feed and calcium carbonate saturation state (Marble test), Had not exceeded AL so corrosion control not formally established, Lead AL exceedance in late 2015, Resumed caustic soda (NaOH) feed in January, 2016, and Raise pH. Sequential Sampling: Series of samples taken after stagnation, First samples typically 125-250 mL, Later samples 1 L (uniform plumbing), Correlate sample volumes to plumbing sections, Useful for identifying lead sources and remedial actions-flushing & plumbing replacements,Captures lead peaks from LSL or other plumbing that a 1 L sample may miss, Requires a large number of samples- time and cost intensive, More complicated to produce an Action Level or interpretation standard. Conclusions: Medium-sized community water system with fluctuating source water exceeded lead action level (pH adjustment), Orthophosphate addition (3 mg PO4/L goal) and pH adjustment (7.5 goal) were implemented, Jar testing was used to screen for unintended consequences (precipitation of phosphates), Sequential sampling (and LCR sampling) was used to assess overall corrosion control progress with time, and Seasonal fluctuations in lead were observed and Lead levels decreased with time. Unintended consequences of orthophosphate treatment were not observed.
Description:
Presentation on lead to be given at the AWWA ACE Annual Conference in Las Vegas. Presentation on lead to be given at the AWWA ACE Annual Conference in Las Vegas. Corrosion Control Treatment: Prior 2010, caustic feed and calcium carbonate saturation state (Marble test), Had not exceeded AL so corrosion control not formally established, Lead AL exceedance in late 2015, Resumed caustic soda (NaOH) feed in January, 2016, and Raise pH. Sequential Sampling: Series of samples taken after stagnation, First samples typically 125-250 mL, Later samples 1 L (uniform plumbing), Correlate sample volumes to plumbing sections, Useful for identifying lead sources and remedial actions-flushing & plumbing replacements,Captures lead peaks from LSL or other plumbing that a 1 L sample may miss, Requires a large number of samples- time and cost intensive, More complicated to produce an Action Level or interpretation standard. Conclusions: Medium-sized community water system with fluctuating source water exceeded lead action level (pH adjustment), Orthophosphate addition (3 mg PO4/L goal) and pH adjustment (7.5 goal) were implemented, Jar testing was used to screen for unintended consequences (precipitation of phosphates), Sequential sampling (and LCR sampling) was used to assess overall corrosion control progress with time, and Seasonal fluctuations in lead were observed and Lead levels decreased with time. Unintended consequences of orthophosphate treatment were not observed.