Contamination of drinking water

Until now, the availability of organic carbon has been considered the key factor controlling microbial regrowth in drinking-water networks. This availability is considered to be a potentially serious problem, especially in boreal regions (northern Europe, Russia and North America) where surface water, and sometimes ground waters, contain high amounts of organic matter. Natural organic matter acts as a substrate for microbial growth and, when water is used for public supply, disinfectants such as chlorine, hypochlorite and ozone are used. In addition to killing microorganisms, these oxidizing agents break down large organic compounds to smaller ones. These compounds can be easily decomposed, further increasing microbial growth in the distribution system and thus impairing water quality. Because of this, considerable effort and resources have been deployed to remove the organic contaminants from drinking water. In the United States, for example, current annual expenditure exceeds 5 billion dollars.