不同负荷下生物膜脱落与载体生物膜生物特性的相互影响

为探究不同负荷下生物膜的脱落特性,对试验过程中生物膜脱落量及载体上生物膜生物特性进行了研究.结果表明:生物膜脱落量随运行时间延长而增大;有机负荷对生物膜脱落量的影响不同,负荷高脱落量大.紧密结合胞外聚合物(TB-EPS)是生物膜胞外聚合物(EPS)的主要组成部分,生物膜EPS量随负荷的增大而增大;EPS中多糖含量越高,生物膜脱落量越小.系统中pH值逐渐下降并抑制生物膜活性,生物膜脱落量随着脱氢酶活性的下降而增加,载体上生物膜脱氢酶活性也会随着生物膜脱落量的增加而下降.生物膜脱落过程中,生物膜微型动物多度、物种数减少,物种多样性水平随着运行时间延长而降低;有机负荷较高,生物膜微型动物多样性较高,物种稳定性指数WS较高而多样性稳定性指数WH较低,但其生物膜脱落量大.因子分析揭示了不同负荷下生物膜脱落与生物膜特性的相互关系,与生物膜脱落紧密相关的因子依次为生物膜组成与活性因子、生物因子、负荷因子等.生物膜脱落与载体上附着生物膜相互作用、相互影响.

Relationship between biofilm detachment and biofilm biological characteristics under different organic loading

To explore characteristics of biofilm detachment under different organic loadings, the biomass loss of biofilm by the natural detachment way and biological characteristics of biofilm attaching on carriers were studied. The results show that the detachment biomass of biofilm increased with running time, and the effect of organic loading on the detachment of biofilm was different, namely, higher organic loading causes more biomass detached. Tightly bound extracellular polymeric substances (TB-EPS) were the main component of EPS that increased with higher organic loading. The detachment biomass of biofilm was counter related to polysaccharide contents. The activity of biofilm was inhibited gradually, since the pH of the reactor decreased over time, and the biomass loss of biofilm increased with the declining dehydrogenase activity and vice versa. During the biofilm detachment process, microbial population and abundance of biofilm decreased with the running time. Themicrobial diversitywas high under the high organic loading; nevertheless, the biomass loss of biofilm was large, so high organic loading would raise microfauna community stability of species and reduce microfauna community stability of species diversity. The results of factor analysis showed that the relationship between biological characteristics of biofilm and its detachment under different organic loadings, and factors closely relating to biofilm detachment are the composition and activity of biofilm, biological factor, and load factor etc.. Both biofilm detachment and biofilm on the carrier interact and affect each other.