[Acclimating, screening of dominant bacteria for degrading pentachlorophenol and its degradation condition study]

To acclimate, screen the dominant bacteria for degrading pentachlorophenol and its growth characteristics and degradation conditions study.

Active sludge aeration and method of density gradient were used to acclimate the sludge. Using pentachlorophenol as a sole carbon source, it was increased step by step in continuous eight weeks. The biodegradation test on pentachlorophenol was conducted after isolation, purification of the dominant bacteria. The suitable temperature, the growth characteristics under different osmotic pressure and the proper degradation conditions of the dominant bacteria were investigated. According to the morphological characteristic, physiological and biochemical, the strain was preliminarily identified.

Three strains of dominant bacteria were screened. The degradation rates of one strain among them on pentachlorophenol could reach to 98.64% in 48 h. The degradation effect would be better when the temperature was 30 degrees C, pH was 6, and the concentration of pentachlorophenol was 0.2-0.4 g/L. The strain could grow best under 30 degrees C. It was halotolerant bacteria and identified as Acetobacter.

The dominant bacteria could be got through density gradient acclimatization in the active sludge aeration basin and its degradation effect on pentachlorophenol was obvious.