Treatment to Remove Inorganic Contaminants

Reverse osmosis or ion exchanges are used to remove nonmetal inorganic contaminants. Nitrate and fluoride are the nonmetals of greatest health concern in drinking water. Nitrate is frequently found in ground- water supplies in high-density agricultural areas. Likely sources of groundwater nitrate are nitrogen fertilizers as well as decomposing plant and animal wastes, including human waste from septic systems.

Coagulation and filtration, reverse osmosis, ion exchange, or activated aluminas are used to remove metal inorganic contaminants. The metals of greatest health concern in drinking water include mercury, cadmium, selenium, lead, arsenic, chromium, and barium. Industrial sources can contribute rare metals and toxic heavy metals to surface waters.
Controlling corrosion of inorganic chemicals from the distribution or plumbing system is another treatment alternative. Corrosion of plumbing by-products such as copper and lead at the point of use (the consumer’s tap) can usually be indirectly eliminated by controlling pH and water hardness.

Lead contamination is the most serious threat from corrosion. Lead usually enters the water from private plumbing where it is found in solder used to connect copper pipes. Lead can also be corroded from public distribution system pipes and joints.
Aeration effectively strips radon gas from source waters. Oxidation and aeration will remove hydrogen sulfide gas.