Reduction of excess sludge and characterization of microbial community in biopolymer-using biological wastewater treatment processes

研究了生物降解塑料（PHBV、PCL和PIA）对活性污泥法中微生物生长和絮凝活性的影响。由标准曝气工艺和PHBV固相反硝化工艺组成的多相活性污泥系统产生的剩余污泥比常规活性污泥工艺减少20-30%。此外，这种多系统具有高反硝化活性。利用平板计数法在非选择性琼脂培养基上定量分离到的优势细菌大多数不能降解PHBV，通过对16 S rRNA基因序列信息nirS和nosZ基因克隆文库的研究，将其鉴定为β-变形菌纲（Betaproteobacteria）属的成员。对来自反应器的微生物群落的基于分析表明，大多数nirS和nosZ克隆被证明来自该家族的成员研究了添加化学解偶联剂3，5-二氯苯酚（DCP）对活性污泥中微生物生长的影响。在活性污泥反应器中投加3，5-DCP后，剩余污泥量显著减少，但BOD去除率没有明显下降。然而，在用3，5-DCP的反应器的长时间操作期间，这种影响被消除。在这次行动中发生了从β变形菌到α变形菌和放线菌的种群转移。通过添加可生物降解塑料PHBV，消除了3，5-DCP对微生物生长的抑制作用。当活性污泥在pH为4的无机介质中运行时，发生了嗜酸性硝化，随着运行时间的延长，生物量逐渐减少。

Effects of the addition of biodegradable plastics (PHBV, PCL, and PIA)on microbial growth and denitrifying activity in activated sludge process were investigated. A multi-phase activated sludge system consisting a standard aeration process and a sold-phase denitrification proems with PHBV produced 20-30% reduced excess sludge compared to the normal activated sludge process. Also, this multi-system had a high denitirication activity. Most of the predominant denitrifiers isolated quantitatively by the plate-counting method using non-selective agar medium were unable to degrade PHBV and were identified as members of genera of the class Betaproteobacteria by studying 16S rRNA gene sequence information nirS and nosZ gene clone library-based analyses of the microbial community from the reactor showed that most of the nirS and nosZ clones proved to be derived from members of the family Comamonadaceae and other phylogenetic groups of the Betaproteobacteria.Effects of the addition of a chemical uncoupler; 3,5-dichlorophenol (DCP), on microbial growth in activated sludge were also investigated. The addition of 3,5-DCP in an activated sludge reactor resulted in the significant reduction of excess sludge without a great decrease in BOD removal. However, this effect was eliminated during the prolonged operation of the reactor with 3,5-DCP. Population shifts from Betaproteobacteria to Alphaproteobacteria and Actinobacteria took place during this operation. The inhibition of microbial growth by 3,5-DCP was eliminated by the addition of biodegradable plastic such as PHBV.When activated sludge was gown with mineral medium at pH 4, acidophilic nitrification took place In this process, the biomass decreased gradually with operation time.