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Corrosion Control in a Small Water System with Lead Service Lines: A Case Study
Citation:
Lytle, D. Corrosion Control in a Small Water System with Lead Service Lines: A Case Study. Region 4 AWOP Meeting and Corrosion Control Workshop, Cincinnati, OH, July 17 - 18, 2018.
Impact/Purpose:
To facilitate the development of an area-wide optimization program within the participating states and EPA Region 4, utilizing the strategic implementation process. 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 Raise pH Sequential Sampling: Required by OEPA Eighteen different homes in sampling pool 5 to 8 homes sampled on a monthly basis for 25 months+ Many homes dropped out of poolNon-LSL homes LSL removed Home vacant 2-125 mL samples followed by 1 L samples depending on on-site plumbing assessment Lead, copper and zinc measured 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 Seasonal fluctuations in lead were observed Lead levels decreased with time Unintended consequences of orthophosphate treatment were not observed
Description:
To facilitate the development of an area-wide optimization program within the participating states and EPA Region 4, utilizing the strategic implementation process. 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 Raise pH Sequential Sampling: Required by OEPA Eighteen different homes in sampling pool 5 to 8 homes sampled on a monthly basis for 25 months+ Many homes dropped out of poolNon-LSL homes LSL removed Home vacant 2-125 mL samples followed by 1 L samples depending on on-site plumbing assessment Lead, copper and zinc measured 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 Seasonal fluctuations in lead were observed Lead levels decreased with time Unintended consequences of orthophosphate treatment were not observed