Corrosion by Urban Cooling Waters

Untreated recirculating cooling waters are likely to become corrosive when low alkalinity waters are present in an area where there is a relatively high sulfur dioxide air content. Untreated circulating cooling waters are compared with makeup waters for eight Eastern cities for such factors as pH, alkalinity, chloride content, sulfate/chloride ratio, and corrosion products. New York City water is discussed specifically. Corrosion can be mitigated by alkaline pH adjustment with maintenance of satisfactory chromate concentrations. 4.6.4