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This powerpoint presentation begins by providing a brief overview of disinfection byproduct (DBP) formation. Study objectives were to: investigate the roles of pH, bromide and nitriteconcentrations on the formation and speciation of Halonitromethanes(HNMs) under Uniform Formation Conditions (UFC) fordifferent oxidation/disinfection scenarios -chlorination,chloramination,ozonation,ozonation-chlorination, andozonation-chloraminationtypically used during drinking water treatment; and, tocompare side by side trihalomethane (THM) and HNM formations. Study approach and analytical methods are presented. Study conclusions for HNM precursors indicate that:the major precursors of HNMs and THMs are not the same innatural waters;conventional treatment removes THM precursors but not veryeffective in removing HNM precursors; and,hydrophilic natural organic matter (NOM) components in natural waters are the majorHNM precursors. Study conclusions for Bromide, nitrite, and pH effects indicate that:during chlorination, bromide effect on HNM formation was notapparent;during ozonation-chlorination, increase in bromideconcentration increased HNM formation significantly; and,in the presence of high bromide levels, the speciation of HNMswill shift from chlorinated HNMs towards brominated species; the presence of nitrite significantly increases HNMconcentrations during chlorination and ozonation-chlorination; and,HNM formation increased with pH. Study conclusions for disinfectant effects indicate that:at typical drinking water treatment conditions, HNM formation willbe the most problematic using ozonation-chlorination; and,one way to minimize HNM formation in the ozonation plants is touse chloramination for post disinfection, or practice biofiltration. Includes tables, figures.

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Edition: Vol. - No. Published: 11/01/2009 Number of Pages: 21File Size: 1 file , 1.1 MB