高效苯降解菌的筛选鉴定及其在生物过滤塔处理苯的填料选择

Isolation and identification of a benzene-degrading strain and choice of packing material during degradation of benzene in biofilter

从污水处理厂曝气池的活性污泥筛选出1株苯的高效降解真菌HD-3,经形态特征、ITS基因序列系统学分析,确定HD-3为杂色曲霉Aspergillus versicolor,该菌株8 d内对初始浓度439.3 mg/L和4 393 mg/L的苯的降解率分别为78.56%和33.96%。当苯的初始浓度为439.3 mg/L,HD-3降解苯的最适温度为30℃,最适pH为4.5。在此基础上,提出了采用不同填料生物过滤塔处理苯废气的工艺,并进行了实验研究,实验结果表明:(1)随着苯的浓度提高,苯的降解率逐渐降低。当苯的浓度为200 mg/m3时,煤质柱状活性炭生物过滤塔、生物陶粒生物过滤塔、竹材生物过滤塔的苯平均去除率(REave)分别为93.63%、93.16%和82.38%;当苯的进口浓度增加到3 000 mg/m3时,3种生物过滤塔的苯平均去除率(REave)分别为78.89%、68.43%和51.87%。(2)不同填料对苯的去除能力不同,煤质柱状活性炭>生物陶粒>竹材。

A fungi HD-3 that can effectively degrade benzene was isolated form sludge collected from the aeration tank in sewage treatment plant. Strain HD-3 was identified as Aspergillus versicolor according to its mor- phological characteristics and sequence analysis of ITS. 78.56% of benzene was degraded by strain HD-3 within 8 days under the conditions of initial benzene concentration of 439.3 rag/L, but only 33.96% of benzene was degraded within 8 days under the conditions of initial benzene concentration of 4 393 mg/L. The most suitable temperature was 30~C and the most suitable pH was 4.5 when benzene concentration was 439.3 mg/L. On the basis of this, the process of biofilter with different packing material was put forward to remove benzene from ex- haust gases, a series of experiments were carried out. The experimental results show that benzene removal effi- ciency gradually decreased with the benzene concentration increasing. The REaveof CQC biofiher, BCC biofilter, BAM biofilter were 93.63% , 93.16% and 82.38% , respectively when benzene concentration was 200 mg/m3 ; the REaveof three biofilters were 78.89% , 68.43% and 51.87% , respectively when benzene concentration was 3 000 mg/m3. The benzene removal capacity of packing material decreased in the order of coal quality columnar carbon, bio-ceramic and bamboo.