AWWA JAW70394

Lead and Copper Rule (LCR) compliance monitoringis intentionally biased toward sites thatexhibit elevated lead rather than elevated copper,but water utilities, especially those with higherpercentages of newer copper piping, need to beaware that copper concentrations above the actionlevel (AL) may be present in their systems. Orthophosphatedoses at sufficient concentrations canhelp high-alkalinity groundwater systems (eventhose with new plumbing) meet the copper AL.The theoretical cupric-hydroxide copper-solubilitymodel predicts that as pipe ages, tenorite ormalachite forms and predominates as the surfacephase, lowering copper levels. Orthophosphatedosing, however, can prevent the reduction ofcopper solubility over years and decades, with theresult that systems which do not use corrosioninhibitors likely will experience copper levelslower than what would be achieved withorthophosphate. Using the information presentedhere, water suppliers will be better able to evaluatethe tradeoff between orthophosphate treatmentversus pH and/or alkalinity adjustment tomeet the LCR. Includes 17 references, tables, figures.

Product Details

Edition:

Vol. 101 - No. 7

Published:

07/01/2009

Number of Pages:

12

File Size:

1 file , 920 KB