Comparison of Excess Sludge Reduction Effect of Dichlorophenol Isomers

Abstract

Differences in sludge reduction effect due to chlorinated sites of dichlorophenol (DCP) isomers used in an uncoupling method were investigated. The study involved two different experiments. A batch experiment conducted to examine the effect of DCPs on SOUR clearly indicated that 3,5-DCP exhibited the strongest uncoupling activity. In the second experiment, in which six different sequence batch reactors were amended with 100 mM DCPs and operated for 2 months, 3,5-DCP also exhibited the strongest sludge reducing effect. The operations examined in this research maintained the concentration of DCPs at 100 mM, and reactors added with 3,5-DCP produced a COD removal rate of >80%, with almost no excess sludge generated in 2 months of continual operation. These results were not obtained with other DCPs. This is the first study to report differences in the sludge reduction effect associated with the chlorination site in the DCP isomer. The results indicate that 3,5-DCP is the most effective option for use in uncoupling methods involving DCPs.