苯乙烯生物滴滤塔生物膜填料的细菌数量分布

Bacteria Distribution of Biofilm and Packing Medium in Biotrickling Filter Treating Styrene-polluted Gaseous Streams

采用培养驯化污泥菌种、陶粒、循环液装置等构建三个生物滴滤塔。测定不同苯乙烯负荷生物滴滤塔装置不同高度生物膜填料的细菌数量分布,认识苯乙烯浓度对填料细菌数量分布的影响。结果表明,生物膜填料柱细菌数量分布依赖于入口气体苯乙烯浓度和停留时间,在低入口气体苯乙烯浓度(Cin<500mg/m3)时细菌数在柱子底部达到最大值而沿柱子自下而上逐渐降低,受气体停留时间的影响不大;当入口气体苯乙烯浓度Cin=800mg/m3时细菌数在整个柱子上的分布变得相对均匀;而当入口气体苯乙烯浓度超过阈限值Cin=1200mg/m3时细菌分布行为出现了和Cin<500mg/m3时相反的情况,细菌数在柱子顶部达到最大值而沿柱子自上而下逐渐降低。

3 biotrickling filters were built for treating styrene-polluted gaseous streams using enriched sludge bacteria, perlite and liquid medium flow. Experimental data of styrene gaseous stream, gas velocity, liquid flow and bacterial count obtained at different biofilter heights were used to evaluate the pollutant concentration profiles as well as the influence of styrene load on biomass distribution along the packing medium. Results showed that the bacterial count along the packing material depended on both styrene load and gas residence time. At relatively low inlet pollutant concentrations, bacterial count reached a maximum value at the bottom and decreased progressively along the column regardless of the apparent gas residence time due to progressive decrease in styrene availability. By progressively increasing inlet pollutant concentrations, its distribution became relatively homogeneous, whereas the opposite behavior was observed beyond the threshold.