Abstract:Biodegradation of anion-surfactant (LAS) and non-ion surfactant (NIS) in water of Lake Dianchi under the different incubationconditions were studied by the ‘river die-away' method in this paper. The results showed that LAS and NIS could be biodegradated bymicroorganisms in the water of Lake Dianchi. The percentages of degradation of LAS and NIS were more than 95% and 92% after 30days respectively. The biodegradation of LAS and NIS fitted the second kinetic model and the correlation coefficient values were among0.956 to 0.999. Incubation temperature, initial concentrations of surfactants, pH value and nutrients (glucose or Na2HPO4) could affect thebiodegradation of LAS and NIS, Incubation temperature was the major factor influence on biodegradation of surfactant in water of LakeDianchi. When the incubation temperature increased from 20 to 30, the biodegradation rate of LAS increased from 0.73 d-1 to 2.10d-1 and the degradation half-life of NIS reduced from 11.5 d to 4.4 d. Increased the initial concentrations of surfactants led to a littleincrease of the degradation half-life of LAS and NIS. The biodegradation of surfactants at pH 7 was slightly easier than that of at pH 10.The degradation of NIS and LAS could be inhibited by added glucose but be promoted by added Na2HPO4. Aeration could accelerate thedegradation of LAS but had limited promotion on the degradation of NIS.