| Toluene has been identified as a major inducer of some diseases, so it is very reasonable to screen some bacterial strains for toluene biodegradation. Five such strains were isolated and screened from soil, and the curves of bacteria concentration changing with time were also determined. Strain ZD5A obtained by UV mutation of ZD5 showed its superiority, and was designated Pseudomonas sp. ZD5A.In this paper, a kind of toluene treatment apparatus- biofilter was designed. Besides, firry wood blocks, ceramics ring, stainless steel θ ring were evaluated as the packing materials. It is concluded that firry wood blocks showed the best performance compared with others on toluene treatment. Under the conditions as follows: experimental temperature 30℃, the inlet gas flow 0.2m3·h-1, relative humidity of packing materials 60%, inlet toluene concentration of less than 500 mg·m-3 and pH 7.0 of culture medium without other carbon nutrition. The toluene elimination efficiency of the filter parked with firry wood blocks was up to 80%.Besides, the operation conditions on toluene treatment of filter A (φ240mm×800mm) and filter B (φ150mm× 1000mm) were analyzed. Generally, the biodegradation efficiency of filter B is better than filter A. During the operation period of 50 days, although in the first few days the efficiency of toluene degradation was unsteady as the inlet toluene concentration varied. Several days after, a steady 85% toluene elimination efficiency of filter B reached under the conditions of inlet toluene concentration of less than 500 mg·m-3.
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