Nitrate contamination of potable water sources is becoming one of the most important water quality concerns. The maximum contaminant level (MCL) for nitrate is 10 milligrams per liter (Mg/L) as nitrogen (N). More information regarding nitrates and California regulations is available on the California Water Boards website.
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Nitrates are known to be found in drinking water and contamination is normally associated with septic systems, certain animal feeding operations, or fertilizer usage. Nitrate/Nitrite can interfere with the ability of red blood cells to carry oxygen to the tissues of the body. More information regarding nitrates and California regulations is available on the California Water Boards website.
Once a water supply becomes contaminated with nitrate, it is costly to treat. Ion exchange and reverse osmosis treatment units are used to remove nitrate from drinking water. Boiling water does not remove nitrates and is not a treatment alternative. More information regarding treatment process of nitrates is available online.
“Ion exchange resin beds, which are part of the treatment unit equipment, are often an attractive growth medium for biological organisms such as bacteria, mold and algae. In some cases, these growths can build up in the resin bed and physically foul the resin. In most cases, however, the concern is that these organisms will contaminate the effluent water leaving the ion exchange system and entering the drinking water supply.” More information on resin sterilization can be found online.
The goal of disinfection for public water systems is to eliminate pathogens that are responsible for waterborne diseases. More information can be found on the National Center for Biotechnology Information, U.S. National Library of Medicine website.
Filtration treatment systems can be an attractive growth medium for biological organisms such as bacteria, mold and algae. In some cases, these growths can build up in the filters. In most cases, however, the concern is that these organisms will contaminate the water leaving the treatment system and entering the drinking water supply. Therefore, potable water supplies generally contain chlorine, which is added as a disinfectant. More information on resin sterilization can be found online.
“Chlorination is the process of adding chlorine to drinking water to disinfect it and kill germs. Different processes can be used to achieve safe levels of chlorine in drinking water. Chlorine is available as compressed elemental gas, sodium hypochlorite liquid solution or solid calcium hypochlorite. While the chemicals could be harmful in high doses, when they are added to water, they mix in and spread out, resulting in low levels that kill germs but are still safe to drink.” Chlorine levels up to 4 milligrams per liter (mg/L or 4 parts per million (ppm) are considered safe in drinking water. More information can be found on the Center for Disease Control and Prevention website.
“Chlorine was first used in the U.S. as a major disinfectant in 1908 in Jersey City, New Jersey. Chlorine use became more and more common in the following decades, and by 1995 about 64% of all community water systems in the United States used chlorine to disinfect their water.” More information can be found on the Center for Disease Control and Prevention website.