 Corrosion Control in Municipal Water Systems
Drinking water suppliers in many parts of the United States and Canada have difficulty in meeting the limits for lead and copper in potable water allowed by the EPA. The method of corrosion control chosen by a municipality can have far-reaching effects on overall operational costs beyond those for metals control.
Bicarbonate alkalinity is a natural ingredient of most water supplies. Waters that are deficient in this key parameter due to acid rain or other causes are often corrosive. Supplementing waters with sodium bicarbonate to restore the alkalinity level between 30 and 40 mg/L as CaCO3 (and an optimum pH between 7.5 and 8.5) reduces the corrosiveness of the water and creates a thin, tenacious, carbonate coating on the interior of lead and copper pipes. This coating effectively seals the interior surface of the pipes from water and significantly reduces the leaching of metals.
Other Potable Water process considerations
In addition to metals and corrosion control, the use of sodium bicarbonate can improve the performance of other water treatment chemicals. Proper bicarbonate alkalinity is required for the optimization of other water processes such as chlorination, flocculation and coagulation and can lead to significant savings. Unlike phosphates, sodium bicarbonate does not promote biofilm growth by providing needed nutrients.
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