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The impacts of alum coagulation on the distribution of disinfection byproducts (DBPs),trihalomethanes (THMs) and haloacetic acids (HAAs), were evaluated under controlledchlorination conditions using four surface waters. Among the nine HAAs found inwaters, dihaloacetic acids (Xsub2/subAAs) have been found to be the dominant species in all ofthe raw and alum treated waters. Alum coagulation tends to remove moremonohaloacetic acids (XAAs) and trihaloacetic acids (Xsub3/subAAs) precursors than that ofdihaloacetic acids (Xsub2/subAAs). Alum coagulation treated water had a lower HAAsub9/sub/TTHMratio compared with that of the raw water. The increase of THM bromine incorporationfactors (BIFsub/sub) value of alum treated water was statistically significant in comparison withthe raw water. On average, BIFsub/sub increased by 54% after the alum coagulation process inthese four different waters. This indicated that THM speciations shifted in favor of themore brominated compounds. However, alum coagulation treatment process had lesseffect on HAA bromine incorporation factors (BIFsub/sub) than it did on BIFsub/sub. BromineIncorporation Factor (BIF) values decreased with time in the THM and HAA formationprocesses, especially within the first 10 hours of the reaction time. This suggested thatbrominated THMs or HAAs formed faster than the chlorinated species in the initialperiod. Includes 22 references, tables, figures.

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Edition: Vol. - No. Published: 11/15/2004 Number of Pages: 15File Size: 1 file , 260 KB