Abstract: To improve the degradation efficiency of phenol in wastewater, mixed bacteria were constructed by using the synergistic effects among three bacterial strains. The proportion of strains was optimized with orthogonal experiment. Then the mixed bacteria were adopted to degrade phenol with an initial mass concentration ranging from 400 to 1400 mg/L. Meanwhile, Three-half-order model was proposed for the first time to describe the degradation kinetic of phenol. The results showed that the mixed bacteria with optimized composition and proportion were able to increase the degradation efficiency of phenol to 99.85%. Compared with first order kinetic model, Three-half-order model with fitted parameters brought better prediction of the degradation kinetics of phenol. This study provides an insight into the biological degradation of phenol wastewater with mixed strains and its degradation kinetics.

Key words: phenol, biodegradation, mixed bacteria, kinetics, sewage treatment