[The formation of trihalomethanes precursor in anionic surfactant biodegradation].
Trihalomethanes (THMs) formed by chlorination of precursor substances in raw water, are found in drinking water. They are found at concentration levels higher than those of other organic contaminants. In the present study, the relationship between the formation of THM precursors and anionic surfectants biodegradation was investigated. Three anionic surfectants (LAS, AS and soap), dissolved in river
Chlorination of Organics in Drinking Water
Recently there has been great interest in the study of organic compounds in drinking water interest that stems largely from the results of a 1974 study of New Orleans drinking water, and the publicity that followed. 1 About the same time, two studies-"" called attention to the presence in finished drinking water of some trihalomethanes (mostly chloroform) which were not found in the respective raw waters at the locations of study. Both reports concluded that the trihalomethanes were formed during the Chlorination step of the water treatment process. The EPA undertook a survey of 80 selected cities to measure the concentrations of six halogenated compounds in raw and finished water. Those six included four trihalomethanes (chloroform, bromodichloromethane, dibromochloromethane, bromoform) suspected of being formed during Chlorination, plus carbon tetrachloride and 1,2-dichloroethane, known contaminants at New Orleans, but not necessarily formed on Chlorination. During this National Organics Reconnaissance Survey (NORS) a more comprehensive organic analysis was also performed in five of the 80 cities and has just been completed in another five. The occurrence of trihalomethanes in finished drinking water was demonstrated to be widespread and a direct result of the
Haloforms in Drinking Water
final product, either by reducing the precursor before chlorination or by removing once-formed haloforms by additional treatment steps. When fulvic acids, or yellow acids, imparting natural color to water combine with chlorine, a group of haloform compounds is formed. These compounds appear in surface waters and in many ground waters.* In order to provide insight into the effects of the rate-determining conditions for the haloform reactions, the variable factors of time, pH, temperature, and concentration were selected for experimentation. In practical water treatment the freedom to vary these conditions is limited; e.g., temperature can hardly be controlled economically; pH can be controlled only within a rather narrow range (6-8), and limits are set upon