CORROSION IN DRINKING-WATER DISTRIBUTION-SYSTEMS - A MAJOR CONTRIBUTOR OF COPPER AND LEAD TO WASTEWATERS AND EFFLUENTS

Corrosion, even in water supply systems with treatment to reduce it, c an be a major contributor of copper and lead to both treated municipal (publicly owned treatment works, POTW) wastewater effluents and bioso lids. Lead and copper concentrations were measured at several points i n the water/wastewater systems of four Massachusetts municipalities. D omestic wastewater was found to contain concentrations of lead and cop per significantly higher (p < 0.05) than those in source waters. For e ach facility, the median concentration of Cu in domestic wastewater wa s a substantial fraction of the median concentration found in the infl uent to the POTWs with ratios of 0.36, 0.41, 0.65, and 1.25 for Gardne r, New Bedford, Fall River, and Clinton, respectively. The values for lead, in the same order, were 0.28, 0.19, 0.17, and 0.69 (this last ra tio based on mean values). Data from the study indicate that minimizin g influent concentrations of Cu and Pb to POTWs is an important contro l factor since the finding of constant removal efficiency for these tw o constituents means that the higher their concentrations in the influ ent, the higher they will be in the effluent These observations strong ly support the concern that corrosive drinking water contributes subst antially to exceeding, at a minimum, water quality criteria for copper , where dilution of wastewater effluents is low. In turn, this argues for corrosion reduction efforts in water supply systems and the means by which such controls are effected to consider impacts on wastewater as well, which generally is not now done.