The Characteristics Of Biodegradation Of Triclosan On The Activated Sludge And Isolation And Identification Of The Triclosan-degrading Bacterium

Triclosan（TCS）,as a broad-spectrum antibacterial agent,is frequently detected in environmental samples,such as surface water,sediment,sludge,soil,which has attracted people’s attention on its environmental security problems.This paper used the activated sludge acclimated by SBR process to study on the adsorption and degradation of TCS,meanwhile,isolation and identification of TCS-degrading bacterium were studied.The degradation of different initial concentrations of TCS by the acclimated activated sludge at different reaction temperatures was studied.The results showed that the biodegradation of TCS at 10℃ 30℃ was effective by acclimated aerobic activated sludge,while it was ineffective by anoxic and anaerobic activated sludge.When the initial concentrations of TCS were 500,1000 and 2000 μg·L^-1,the apparent removal rates of TCS were above 98.5% under aerobic condition,among them,the biodegradation rates contributed about 40.22% 98.53%.The process of TCS degradation by aerobic activated sludge fitted to first-order reaction kinetics with the half-life（t1/2）ranged from 3 h to 30 h.The apparent removal rates were above 95.86% under anoxic condition,and the sludge adsorption played a dominant role in the removal rates with no biodegradation phenomenon.The apparent removal rates were above 95.12% under anaerobic condition,and it showed the same phenomenon that no biodegradation was observed.TCS was adsorbed on the activated sludge at the degradation process of TCS by aerobic activated sludge.Therefore,the Linear,Langmuir,Freundlich and Temkin adsorption isotherm were used to fit the adsorption phenomenon of TCS by aerobic activated sludge.The results showed that the adsorption phenomenon of TCS by aerobic activated sludge was well described by Linear and Freundlich adsorptionisotherm.When the temperatures were 10℃,20℃ and 30℃,the Kd of Linear isotherm were 12198,10469 and 8332.4 L·kg^-1,respectively;The KF of Freundlich isotherm were 7760.68,6341.62 and 5262.60 mg1-n·Ln·kg^-1,respectively,and nF were approached 1,showed that it was accorded with Linear isotherm.The strain of with high-efficient of degrading TCS,was isolated from acclimated aerobic activated sludge,named YZ^-1.Through the optimization of degradation conditions,when the pH value was 7,the inoculation amount was 2%,the reaction temperature was 30 ℃,after 48 h reaction,the degradation rates of the initial concentration of 10 mg·L^-1 TCS were above 95%,indicating the high efficiency of biodegradation.