Corrosion occurs because metals tend to oxidize when they come in contact with oxygenated water, resulting in the formation of stable metal oxides. Corrosion in water distribution systems can impact consumers’ health, costs, and the aesthetics of finished water. Older systems may include lead based solders which must be protected to avoid elevated lead concentrations which is regulated by the EPA at ≤0.015 mg/L.
Corrosion inhibitors such as inorganic phosphates in the form of polyphosphates, orthophosphates, glassy phosphates, and bimetallic phosphates are often employed. To ensure proper corrosion control, correct feed and to reduce operating cost reliable monitoring is required.
Image credit: "R.C. Harris Water Treatment Plant - Filter Room being backwashed," © 2011 Andrew Morgan., used under an Attribution-NoDerivs 2.0 Generic license: http://creativecommons.org/licenses/by-nd/2.0/deed.en