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유혜원,오상근,In S. Kim,Ian Pepper,Shane Snyder,장암 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.26 No.-
To evaluate the formation potential of disinfection byproducts (DBPs) in a SWRO system when chlorine dioxide (ClO2) is used as a chemical disinfectant, the impact of principle precursors such as natural organic matter (NOM) and bromide ion on haloacetic acids (HAAs) formation and its speciation was investigated. In the presence of high bromide levels found in seawater, the active oxidizing agents formed by the action of ClO2 can react with NOM, resulting in halogenation reactions, and the production of brominated DBPs as the predominant byproducts. Elevating the initial levels of organic substances and bromide ions not only enhanced the total content of HAA5 formed, but also shifted the speciation of HAAs from the chlorinated to fully brominated forms at higher disinfectant doses and longer contact times of ClO2 disinfection. In addition, HAA5 formation potential increased in the order of transphi- lic > hydrophobic > hydrophilic NOM, suggesting HAA5 yield formed during ClO2 disinfection significantly depends on the characteristics of NOM that can lead to different speciation distribution of DBPs. However, at high doses of ClO2, it was observed that the disinfectant dose plays a more important role in speciation distribution of HAA5 than the characteristics of organic precursors.
Lee, Yunho,Gerrity, Daniel,Lee, Minju,Bogeat, Angel Encinas,Salhi, Elisabeth,Gamage, Sujanie,Trenholm, Rebecca A.,Wert, Eric C.,Snyder, Shane A.,von Gunten, Urs American Chemical Society 2013 Environmental science & technology Vol.47 No.11
<P>Ozonation is effective in improving the quality of municipal wastewater effluents by eliminating organic micropollutants. Nevertheless, ozone process design is still limited by (i) the large number of structurally diverse micropollutants and (ii) the varying quality of wastewater matrices (especially dissolved organic matter). These issues were addressed by grouping 16 micropollutants according to their ozone and hydroxyl radical (<SUP>•</SUP>OH) rate constants and normalizing the applied ozone dose to the dissolved organic carbon concentration (i.e., g O<SUB>3</SUB>/g DOC). Consistent elimination of micropollutants was observed in 10 secondary municipal wastewater effluents spiked with 16 micropollutants (∼2 μg/L) in the absence of ozone demand exerted by nitrite. The elimination of ozone-refractory micropollutants was well predicted by measuring the <SUP>•</SUP>OH exposure by the decrease of the probe compound <I>p</I>-chlorobenzoic acid. The average molar <SUP>•</SUP>OH yields (moles of <SUP>•</SUP>OH produced per mole of ozone consumed) were 21 ± 3% for g O<SUB>3</SUB>/g DOC = 1.0, and the average rate constant for the reaction of <SUP>•</SUP>OH with effluent organic matter was (2.1 ± 0.6) × 10<SUP>4</SUP> (mg C/L)<SUP>−1</SUP> s<SUP>–1</SUP>. On the basis of these results, a DOC-normalized ozone dose, together with the rate constants for the reaction of the selected micropollutants with ozone and <SUP>•</SUP>OH, and the measurement of the <SUP>•</SUP>OH exposure are proposed as key parameters for the prediction of the elimination efficiency of micropollutants during ozonation of municipal wastewater effluents with varying water quality.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/esthag/2013/esthag.2013.47.issue-11/es400781r/production/images/medium/es-2013-00781r_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/es400781r'>ACS Electronic Supporting Info</A></P>