Abstract: It is generally thought that biofilm and sediments can harbour microorganisms, especially in chloraminated reservoirs, but their impact on disinfectant loss on disinfectant loss has not been quantified. Hence, debate exists as to the extent of the problem. To quantify the impact, the reservoir acceleration factor (F(Ra)) is defined. This factor represents the acceleration of chloramine decay arising from all causes, including changes in retention time, assuming that the reservoir is completely mixed. Such an approach quantifies the impact of factors, other than chemical reactions, in the bulk water. Data from three full-scale chloraminated service reservoirs in distribution systems of Sydney, Australia, were analysed to demonstrate the generality of the method. Application of a method for quantifying factors affecting chloramine decay in service reservoirs,’ are discussed in a new report. “Service reservoirs play an important role in maintaining water quality in distribution systems. Several factors affect the reservoir water quality, including bulk water reactions, stratification, sediment accumulation and wall reactions,” researchers in Perth, Australia report. “It is generally thought that biofilm and sediments can harbour microorganisms, especially in chloraminated reservoirs, but their impact on disinfectant loss on disinfectant loss has not been quantified. Hence, debate exists as to the extent of the problem. To quantify the impact, the reservoir acceleration factor (F(Ra)) is defined. This factor represents the acceleration of chloramine decay arising from all causes, including changes in retention time, assuming that the reservoir is completely mixed. Such an approach quantifies the impact of factors, other than chemical reactions, in the bulk water. Data from three full-scale chloraminated service reservoirs in distribution systems of Sydney, Australia, were analysed to demonstrate the generality of the method. Results showed that in two large service reservoirs (404 x 10(3) m(3) and 82 x 10(3) m(3)) there was minimal impact from biofilm/sediment. However, in a small reservoir (3 x 10(3) m(3)), the biofilm/sediment had significant impact,” wrote A. Sathasivan and colleagues, Curtin University of Technology. The researchers concluded: “In both small and large reservoirs, the effect of stratification was significant.” Sathasivan and colleagues published their study in Water Research (Development and application of a method for quantifying factors affecting chloramine decay in service reservoirs. Water Research, 2010;44(15):4463-72). For additional information, contact A. Sathasivan, Curtin University of Technology, Dept. of Civil and Construction Engineering, GPO Box U1987, Perth, Western Australia 6845, Australia. Keywords: City:Perth, Country:Australia, Anti Infective Agents, Anti-Infective Agents, Chloramines, Disinfectants, Specialty Uses of Chemicals, Sulfonamides. View Less >>
It is necessary to know what Chloramine is and for which property it is used as disinfectant. When ammonia reacts with hypochlorous acid (HOCL) or aqueous chlorine, three products namely Monochloramine (NH2Cl), Dichloramine (NHCl2), or Nitrogen trichloride (NCl3) are formed. Among the three products, only Monochloramine is used for disinfecting drinking water. Reasons behind neglecting other Chloramine species are odor as well as taste problem. To ensure that Dichloramine and Nitrogen trichloride are not formed appropriate measure should be taken. Among some practices, very common procedure is to limit the ratio of chlorine to ammonia. Generally three parts of chlorine and one part of ammonia can be mixed for the above-mentioned reaction so that Dichloramine and Nitrogen trichloride are not formed. As excess amount of ammonia may cause problems like biofilm growth, nitrification etc. current practice has become to lower the amount of ammonia in the reaction. Get solution

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