title: Distribution variation of a metabolic uncoupler, 2,6-dichlorophenol (2,6-DCP) in long-term sludge culture and their effects on sludge reduction and biological inhibition.
abstract: Distribution variation of a metabolic uncoupler, 2,6-dichlorophenol (2,6-DCP), in long-term sludge culture was studied, and the effects on sludge reduction and biological inhibition of this chemical during the 90-day operation were established. The extracellular polymeric substance (EPS) matrix functioned as a protective barrier for the bacteria inside sludge flocs to 2,6-DCP, resulting in the transfer of 2,6-DCP from the liquid phase to the activated sludge fraction. Significant sludge reduction (about 40%) was observed after the addition of 2,6-DCP in the first 40 days, while the ineffective function of 2,6-DCP in sludge reduction (days 70-90) might be correlated to the EPS protection mechanism. The inhibitory effect of 2,6-DCP on the COD removal was extremely lower than on the nitrification performance due to the fact that 2,6-DCP was much more toxic to autotrophic microorganisms than heterotrophic microorganisms. Moreover, both of them recovered to a higher level again with the transfer potential of 2,6-DCP to sludge. Thus, the application of metabolic uncoupler for excess sludge reduction should be cautious.
authors.affiliation: State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology (SKLUWRE, HIT), Harbin 150090, China. hittianyu@163.com
authors.forename: Yu
authors.initials: Y
authors.lastname: Tian
authors.forename: Jun
authors.initials: J
authors.lastname: Zhang
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.forename: Zhipeng
authors.initials: Z
authors.lastname: Li
authors.forename: Yanni
authors.initials: Y
authors.lastname: Cui
mesh_terms: D000818:Animals; D001419:Bacteria / Q000187:drug effects* / Q000378:metabolism; D001673:Biodegradation, Environmental; D018533:Biomass; D002733:Chlorophenols / Q000737:chemistry* / Q000494:pharmacology*; D058645:Denaturing Gradient Gel Electrophoresis; D058465:Nitrification; D010100:Oxygen; D012722:Sewage / Q000737:chemistry* / Q000382:microbiology*; D014865:Waste Disposal, Fluid
chemical_list: D002733:Chlorophenols; D012722:Sewage; C032729:2,6-dichlorophenol; D010100:Oxygen