ALKALINITY, PH, AND COPPER CORROSION BY-PRODUCT RELEASE

Contrary to expectations, higher bicarbonate concentrations exacerbate copper corrosion rates and by-product release. In fact, as illustrate d by monitoring experiences of large utilities and by laboratory data, the concentration of copper corrosion by-products in drinking water i ncreases linearly with bicarbonate concentration at constant pH. This relationship implicates cupric hydroxide solubility in control of copp er release from relatively new (less than a few years old) copper plum bing. Decision-making guidance from a traditional Larson's ratio or La ngelier index approach can aggravate copper corrosion problems; conseq uently, their use should be discontinued for copper corrosion mitigati on. In contrast, aeration CO2 stripping is a particularly attractive s trategy because benefits from higher pH are realized without adverse e ffects from higher alkalinity.