Chlorination water disinfection

Hypochlorous Acid. Hypochlorous acid [7790-92-3] solutions are made for immediate use as chemical intermediates from chlorine monoxide or in bleaching and water disinfection by adjusting the pH of hypochlorite solutions. Salt-free hypochlorous acid solutions have been economically made... 

Chlorine dioxide yields of 95% or greater have been demonstrated. The use of chlorine as an oxidant has distinct advantages because it is usually present in municipal water treatment plants for water disinfection. 

One of the most widespread methods of water disinfection is it s chlorination. As chloration products ai e toxic, their content is to be controlled. Among them free chlorine and inorganic chloramines ai e predominant in water. Maximum contaminant limit for free chlorine is 0.3 - 0.5 mg/L, for chloramines - 0.8 - 1.2 mg/L. 

What parameters impact on the effectiveness of chlorine as a water disinfectant ... 

Montemayor M, Costan A, Lucena F et al (2008) The combined performance of UV light and chlorine during recalimed water disinfection. Water Sci Technol 57(6) 935-940... 

Chlorine dioxide has been used widely in Europe since the early 1940 s as a drinking water disinfectant. More recently the USA has suggested the use of chlorine dioxide to reduce the formation of chloro-organic compounds particularly chloroform and other trihalomethanes (THM s) which are known carcinogens(7). 

Ultrasound (US) disrupts biological structures and may lead to death when applied with sufficient intensity (Betts and Everis, 2005). The use of ultrasound to disinfect fruit and vegetables has not been described frequently in the literature. The results from a study by Seymour et al. (2002) indicated that a combination of ultrasound and chlorinated water reduced the numbers of both Salmonella Typhimurium and E. coli from iceberg lettuce. However, the authors concluded that the cost of such a method is high and that the combination does not completely remove pathogens from fresh produce. Therefore, this is probably not a well-suited alternative method for the decontamination of fruit and vegetables. 

Beuchat, L.R. (1999) Survival of enterohemorrhagic Escherichia coli 0157 H7 in bovine feces applied to lettuce and the effectiveness of chlorinated water as a disinfectant . Journal of Food Protection, 62, 845-849. 

This book examines comprehensively the chlorine industry and its effects on the environment. It covers not only the history of chlorine production, but also looks at its products, their effects on the global environment and the international legislation which controls their use, release and disposal. Individual chapters are dedicated to subjects such as end use processes, water disinfection and metallurgy, environmental release of organic chlorine compounds, polychlorinated biphenyls, legal instruments and the future of the chlorine industry. 

The use of chlorine for disinfecting wastewaters or drinking water has become widespread in this century. Recently, however, the increasing presence and variety of aquatic contaminants has raised the question of the chemical fate of these contaminants when subjected to aqueous chlorination [36]. In fact, the production of organochlorine compounds in chlorinated water, including mutagenic and carcinogenic substances, is well established [37,38], A number of alternatives to chlorination are used in many parts of the world, but the risks associated with their by-products are even less well established [39],... 

Physical disinfection of drinking water is mainly carried out through photodegradation by ultraviolet radiation (UV). Because many pharmaceuticals have chromophores that absorb UV wavelength, UV irradiation can lead to some transformation. Comparing to chemical oxidation, such as chlorination, UV disinfection has an advantage of minimizing the formation of DBPs [73]. However, at a... 

Lopez A, Mascolo G, Tiravanti G, Passino R (1997) Degradation of herbicides (ametryn and isoproturon) during water disinfection by means of two oxidants (hypochlorite and chlorine dioxide). Water Sci Technol 35 129-136... 

Zambodin CG, Losito II, Palmisano E (2000) Liquid chromatography/electrospray ionisation sequential mass spectrometric identification of the main chlortoluron by-products during water disinfection using chlorine. Rapid Commun Mass Spectrom 14 824-828... 

Chlorine is the oldest and most widespread method of water disinfection. In reverse osmosis systems, chlorine may be added to feedwater for control of micro-organisms and, in addition, to prevent membrane fouling by microbiological growth. According to Vos et al. [i,2], chlorine will attack cellulose diacetate membranes at concentrations above 50 ppm. Membranes were found to show a sharp increase in salt permeability and a decrease in strength after one week of continuous exposure. Under milder conditions (10 ppm chlorine for 15 days) no detectable change in performance was observed. Spatz and Friedlander [3] have also found cellulose acetate membranes to be resistant to chlorine when exposed to 1.5 ppm for three weeks. 

Chlorine dioxide has been used as a water disinfectant, showing fewer undesirable side effects than chlorine [6]. This agent was shown by Vos et al. [1] to be unreactive toward cellulose acetate membranes. The compatibility of chlorine dioxide with other membrane types has not been studied. 

Uses. Chlorinating agent disinfectant laundry bleach in water treatment intermediate for drugs insecticides polymerization catalyst... 

Comparative Toxicokinetics. No studies were located in which toxicokinetics of chlorine dioxide or chlorite were examined in humans. Chlorine dioxide is used as a drinking water disinfectant and readily forms chlorite (CIO2 ) in aqueous environments. Therefore, humans would be most likely to encounter chlorine dioxide or chlorite via the oral exposure route. Currently, available toxicokinetic information is restricted to animal studies. Additional studies could be designed to examine toxicokinetics in humans orally exposed to chlorine dioxide or chlorite. Results of human and animal studies could then provide a basis for development of PBPK models for species extrapolation. 

Condie LW. 1990. Toxicological effects associated with drinking water disinfectants and their by-products. In Jolley RL, Condie LW, Johnson JD, et al., eds. Water Chlorination. Chemistry, Environmental Impact and Health Effects. Oak Ridge, Tennessee Lewis Publishers. 

EPA. 1998. Health risk assessmenUcharacterization of the drinking water disinfection by-products chlorine dioxide and chlorite. Washington, DC U.S. Environmental Protection Agency, Office of Science and Technology, Office ofWater. EPA-PB99-111361. 

Gates D, Harrington R. 1993. Drinking water disinfection practices Chlorine dioxide in the nineties. In Disinfection dilemma Microbiol, control versus by-prod.. Proceedings of the National Conference on Drinking Water, 339-363. 

Hoehn RC, Long BW, Gates DJ. 2000. Status of chlorine dioxide disinfection technologies. J Am Water Works Assoc 1888-1906. 

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