活性污泥系统中基质电子转移分配对化学解偶联剂的响应机制研究

The metabolic uncoupling based on chemical uncouplers addition is an effective approach for sludge reduction. The addition of uncouplers had influences on the components and characteristics of microbial products which are significant sinks for electrons from the substrate, resulting in the change of flow and distribution of electrons. However, the flow and distribution of electrons from the substrate under metabolic uncoupling conditions is still unknown. Therefore, the activated sludge system with dosing chemical uncoupler was investigated in this study. Both experimental and mathematical modeling methods were used to determine the effect of chemical uncouplers on pollutant removal efficiency, biochemical properties and community structure of activated sludge. The influences of chemical uncouplers on the contents, components and characteristics of microbial products were investigated. The role of microbial products on the transfer of chemical uncouplers was explored. The fate and degradation path of chemical uncouplers in activated sludge was analyzed. The new activated sludge model was established to describe the flow and distribution of electrons from the substrate under metabolic uncoupling conditions. With the integrated analysis of the inhibited and toxic influences of chemical uncouplers on activated sludge, the mechanism of sludge reduction under metabolic uncoupling conditions were elucidated. Furthermore, integrated model with activated sludge model and intelligence approaches was established to optimize this complex system. Hopefully, this study can provide theoretical basis and technological support for lowering the sludge yield and further maintaining the steady operation of the activated sludge system.

基于化学解偶联剂的代谢解偶联技术可以有效降低活性污泥系统的污泥产率，但是解偶联剂的投加会影响活性污泥系统中微生物产物的组分和性质，从而改变基质电子在活性污泥系统中的转移途径和分配规律。但是目前人们对代谢解偶联条件下基质电子的转移分配规律尚不明晰。本研究以投加化学解偶联剂的活性污泥系统为研究对象，采用试验研究与数学模拟结合的手段，考察化学解偶联剂对活性污泥系统净污能力、理化性质及微生物菌群结构的影响；研究活性污泥微生物产物含量、组分及性质对解偶联剂的响应；探讨微生物产物在解偶联剂迁移转化中的作用及解偶联剂自身的代谢途径；利用新构建的数学模型定量描述代谢解偶联条件下基质电子的转移分配，结合解偶联剂对活性污泥微生物抑制及毒性作用的分析，阐明代谢解偶联条件下污泥减量的机理，并结合计算智能方法优化解偶联剂的最佳投加量，为降低污泥产率、实现废水生物处理系统的稳定运行提供可靠的理论依据。

基于化学解偶联剂的代谢解偶联技术可以有效降低活性污泥系统的污泥产率，但是目前人们对代谢解偶联条件下基质电子的转移分配规律依然不清楚。本项目分别采用间歇实验和反应器长期运行实验，利用好氧SBR反应器，解析了化学解偶联剂oCP投加对活性污泥系统净污能力、污泥理化性质及微生物菌群结构的影响，研究了活性污泥微生物产物组分、含量及性质对oCP的响应及oCP与EPS间的相互作用机制；并在此基础上，结合微生物抑制及毒性分析和数学模型，解析代谢解偶联条件下基质电子在活性污泥系统中的转移分配规律及污泥减量机理。.研究结果表明，在SBR反应器中分别投加5，10，15，20 mg/L oCP并进行为期63天的运行后，系统中平均污泥减量率分别为17.40%，25.80%，33.02%和39.5%。oCP的投加会导致污染物的去除效率及污泥絮凝沉降性能有一定程度的降低。利用EEM、FTIR、XPS等多种光谱和能谱分析，明确投加到活性污泥系统中的oCP与活性污泥EPS之间通过EPS上的羧基、羰基、羟基、氨基等官能团发生相互作用，从而使得oCP被吸附在污泥上。基于LB-EPS和TB-EPS分析并借助表面热力学解析，通过扩展DLVO理论计算，发现oCP投加增加了活性污泥微生物间的能量壁垒，从而导致污泥絮凝沉降性能的降低。.投加oCP后SBR系统出水中SMP的含量会降低，但是系统中EPS及胞内贮存物PHA的形成会增加。此外，oCP投加还降低了系统电子传递体系活性，并增加了细胞溶胞作用。因此，代谢解偶联、基质电子分布的改变和细胞溶解是解偶联剂oCP实现污泥减量的主要原理。通过SBR系统中微生物群落分析发现，oCP投加会降低SBR中污泥的丰富度和多样性，且反应器中会出现与酚类降解有关的菌种。.通过项目的实施，确定了oCP投加对活性污泥微生物产物PHA和EPS的刺激作用，明确了oCP与微生物产物EPS的相互作用机制，解析了oCP投加条件下活性污泥系统中污泥减量的机理。该研究成果为代谢解偶联条件下污泥减量的基础研究及应用于污水处理系统的污泥减量提供了科学依据和技术支撑。