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Microbial Breakthroughs in Changing Source, Treatment, or Supply Parameters
Published in Edwin E. Geldreich, Microbial Quality of Water Supply in Distribution Systems, 2020
Another approach to minimize trihalomethane production in water treatment is the use of a disinfectant alternative to free chlorine. Preformed chloramines (chloramination), chlorine dioxide, and ozone have been proposed as practical disinfectant alternatives. In addition, potassium permanganate has been suggested as a preoxidant for some raw source waters. Because of the desire to maintain a disinfectant residual in distribution water, chloramines and chlorine dioxide have received considerable attention. Some surface-water systems are seriously considering ozonation because of its more favorable disinfection C.T values for inactivating Giardia cysts. While ozone is a powerful inactivating agent for waterborne pathogens, it does not have a lasting residual to provide protection in distribution water. Furthermore, ozone is known to create additional assimilable organics that stimulate the growth of heterotrophic bacteria in the distribution system. Each alternative disinfectant candidate has specific advantages over free chlorine application, but also some significant disadvantages that must be understood in the trade-off.
Water Pollution
Published in Frank R. Spellman, The Drinking Water Handbook, 2017
The disinfection byproducts problem stems from the fact that most U.S. water systems produce the unwanted byproducts when the chlorine reacts to decayed organics: vegetation and other carbon-containing materials in water. Communities that take drinking water from lakes and rivers have a tougher time keeping the chlorine byproducts out of the tap than those that use clean groundwater. When a lot of debris is in the reservoir, a water utility may switch to alternative sources, such as wells. In other facilities, chlorine is combined with ammonia in a disinfection method called chloramination. This method is not as potent as pure chlorination, but it does prevent the production of unwanted trihalomethanes.
Water and Wastewater
Published in Gary S. Moore, Kathleen A. Bell, Living with the Earth, 2018
Gary S. Moore, Kathleen A. Bell
Although chlorine is the most widely used disinfectant, other disinfection methods exist, including ozonation, ultraviolet light exposure, and chloramination. Ozone can disinfect water 3100 times faster than chlorine and leaves no residual by-products. However, because ozone does not provide a long-lasting residual, ozonated water is treated with a small dose of chlorine. Chloramination, which involves mixing chlorine and ammonia in the water to create chloramines, also disinfects the water and does not form trihalomethanes. But because chloramination lacks the disinfectant strength of chlorine, the water usually requires a second dose of chemical.63
Drinking water quality in regional Hunter New England, New South Wales, Australia, 2001-2015
Published in Australasian Journal of Water Resources, 2020
Fidelis Godfrey Jaravani, Michelle Butler, Paul Byleveld, David N. Durrheim, Peter. D. Massey, Julie Collins, Jenni A. Judd, Michael Oelgemöller
During the period in review, water supplies in the regional Hunter New England area consisted of dam (15.1%), river (25.8%), bore (51.5%) and river/bore (7.6%) systems. Disinfection methods included chlorination; a combination of chlorination, ozonation and chloramination; UV light; and silver ion. Five bore water supply systems introduced chlorine disinfection during the review period. The rate of E. coli detections in bore water supplies was 7.67 times higher before the introduction of chlorine disinfection (IRR = 7.67, [95% CI 4.24–14.87]; p = <0.0001). The source of contamination could not be verified from the database. The contamination could have been caused by poor quality source water or poor integrity of the distribution system.