AWWA WQTC71468

This powerpoint presentation begins by providing a brief overview of emerging disinfection byproducts (DBPs) and their toxicity. Study objectives for Halonitromethane (HNM) formation were to: investigate the effects of different oxidants and treatment strategies (O₃, Cl₂, O₃-Cl₂, NH₂Cl, O₃-NH₂Cl); investigate the effects of bromide and nitrite concentrations; and, investigate the effect of pH. Objectives for I-THM formation were to investigate the effects of: pH (preformed monochloramine); prechlorination contact time prior to ammonia addition (prechlorination vs. preformed monochloramine); and, preoxidation (KMnO₄, ClO₂, and H₂O₂ w/o UV) prior to preformed monochloramine addition. The experimental approach included: formation potential tests of HNMs - excess amount of ozone, chlorine, monochloramine, ozone-chlorine and ozone-monochloramine were added to different drinking water sources, and the dose of the disinfectants satisfy the disinfectant demands for different water sources with different compositions and also satisfy the oxidant demands of some components such as NH₃ and NO₂^-; uniform formation conditions (HNMs, I-THMs) - chlorine and monochloramine concentrations were added to achieve disinfection residuals of approximately 1.0 mg/L and 2.0 mg/L, respectively, after 24 hours; and, extraction - I-THMs and HNMs were extracted with MTBE and analyzed with gas chromatography equipped with µ-ECD. The effect of oxidants on HNM formation potentials is presented, along with the effect of pH (preformed monochloramine), the effect of treatment strategy (prechlorination and ammonia vs - preformed monochloramine), and the effect of preoxidation (potassium permanganate, chlorine dioxide, and hydrogen peroxide). Includes table, figures.

Product Details

Edition:

Vol. - No.

Published:

11/01/2009

Number of Pages:

17

File Size:

1 file , 1 MB