Chloramination techniques to reduce NDMA formation during disinfection
نویسنده
چکیده
Previous studies modeled NDMA formation during chlorine disinfection as arising from the oxidation of an unsymmetrical dimethylhydrazine intermediate formed from the reaction of monochloramine and dimethylamine. However, chlorination of wastewater effluents indicated that this mechanism could not account for a significant portion of the observed NDMA formation. Laboratory studies indicated that the order of reagent addition can have a significant effect on NDMA formation. Important factors included the chlorination state of organic nitrogen precursors and the formation of dichloramine. Disinfection systems were devised that maximize the formation of chlorinated organic nitrogen precursors and minimize dichloramine formation in order to minimize NDMA formation. Preliminary results from pilot testing indicate the effectiveness of these disinfection scenarios during chlorination of drinking waters and wastewaters. Evidence for a new reaction pathway to explain NDMA formation during chlorine disinfection is presented.
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