Full Description

Despite the documented inefficacy of the calciumcarbonate approach to corrosion control,adjustment of calcium carbonate remains thedominant corrosion control strategy. Many utilitiesstill significantly increase alkalinity (withlimited or no success) or try to operate at muchlower pH values than necessary, both as ameans of lead and copper control.Consistent high pH is the main variablecontrolling release of lead and copper at customertaps. The extent to which pH can beraised must be carefully evaluated on the basisof site-specific conditions. The San FranciscoPublic Utilities Commission (SFPUC) caseprofiled here demonstrates that maintaining ahigh pH is a more appropriate corrosion controltreatment to comply with the Lead andCopper Rule (LCR) than adjusting theLangelier saturation index or augmentingalkalinity. The combination of water qualityand distribution system conditions at SFPUCis such that a switch from free chlorine tochloramine did not affect lead and copperrelease or LCR compliance. Includes 49 references, tables, figures.

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Edition: Vol. 102 - No. 3 Published: 03/01/2010 Number of Pages: 13 File Size: 1 file , 1.1 MB