膜生物反应器中生物膜的生长特性

实验采用经甲苯培养驯化而成的单一假单胞菌菌种,通过分析平板式生物膜反应器内,不同阶段假单胞细菌生物膜干重、厚度、活性生物量和生物种群分布的变化,研究生物膜特性与降解效率之间的关系。实验结果表明,在挂膜初期生物膜迅速生长,生物量以及生物膜干重增长很快,有利于甲苯及营养物质的传输,降解效率也快速提升。随着生物膜的生长,生物量及干重也逐步增加,厚度逐渐增加使传质阻力不断增大,生物膜上层微生物的有机底物供应不足,使生物膜上层结构稀疏,最终维持一个甲苯的总传输量与生化降解量的平衡,生物量的生长与衰亡也达到动态平衡,形成了一个较高且稳定的降解效率。

Growth characteristics of biofilm in membrane bioreactor

A planar membrane bioreactor with pseudomonas bacteria was developed to explore the characteristics of the biofilm formation in terms of the dry weight of formed biofilm, thickness, active biomass as well as its morphology and structure and elucidate the relationship between the biofilm characteristics and removal efficiency in the formation of biofilm. Experimental results showed that at the beginning of the biofilm formation, the biofilm grew fast and the biomass and dry weight rapidly increased as well, facilitating the transfer of both toluene and inorganic nutrients and thus improving the removal efficiency. As the biofilm further grew, the biomass and dry weight gradually increased, leading to an increase in the biofilm thickness. The increased thickness in turn increased the mass transfer resistance so that the supply of toluene for bacteria on the top of biofilm was insufficient, making the biofilm loose in this zone. Eventually, the supplied toluene was balanced by the toluene biodegraded by bacteria and the growth and death of bacterial was also in dynamic equilibrium. As a result, a relatively high and stable toluene biodegradation performance was achieved.