降解乙苯生物滴滤塔稳定运行期生物膜特征及微生物多样性研究

通过检测降解乙苯生物滴滤塔(BTF)长期稳定运行过程中生物量积累、塔内压降改变、生物膜显微结构特征、微生物种群分布及优势菌株分子测序,探讨BTF稳定运行期间生物膜相结构、特征及菌群多样性协作作用的规律.结果表明,生物滴滤塔运行95 d期间的降解性能稳定,降解效率保持在90%以上,最大去除负荷为62.4 g·m~(-3)·h~(-1);BTF稳定运行期间生物膜形态、颜色和厚度沿着BTF塔内废气的流向呈现不均匀分布和梯度改变的特征.生物量和生物膜的致密度沿气流方向逐步递减;塔内压降随着反应时间延长逐渐增加,但未出现堵塞现象;生物膜种群营养结构复杂,食物链长且相互交叉,高端营养级微生物种群所占比例较高;采用聚合酶链式反应-变性梯度凝胶电泳(PCR-DGGE)和分子测序技术研究降解乙苯生物滴滤塔填料表面菌群的分布特征,结果表明,在BTF不同塔层上菌群分布稍有差异,表现出明显的空间多样性,但是整个BTF生物膜具有一定的稳定性,主要的优势菌群为变形杆菌,其中优势菌包括3种伽马变形杆菌和4种贝塔变形杆菌.

Biofilm characteristics and microbial diversity in ethylbenzene degradation BTF during the stable operation periods

The structures, characteristics and microbial diversities of biofilm in biotrickling filter (BTF) for the degradation of ethylbenzene were studied during the long-term stable operation periods. The results show that the degradation performance of ethylbenzene kept stable in BTF during 95 d. The degradation efficiencies were more than 90% while the maximum removal rate was 62.4 g·m^-3·h^-1. along the gas flow direction, The biofilm pattern, color and thickness gradual change and the biomass and biofilm density gradually decreased. The pressure gradually dropped with the increasing operation time, but clogging phenomenon did not appear in BTF. The compositions of microbial community and nutrition structure were complicated. The food chains of microorganisms in biofilm were long and crossed each other. The microorganisms of high trophic level had a higher population. the structure of microbial community in BTF for removal of ethylbenzene was assessed by using PCR-DGGE and sequencing of dominant bacteria. The spatial diversities were significantly found in different biofilter bed. Overall, there were relatively stable bacterial species in BTF biofilm. The dominant bacteria for degradation of ethylbenzene were Proteobacteria, including three predominant Gamma-proteobacteria and four species of Beta-proteobacteria.