絮状污泥中凝胶化关键物质识别及定向酶降解-磁场耦合调理脱水过程研究

Now the production of sewage sludge increases year by year with the rise of wastewater treatment rate in our country, it is necessary to develop the high-efficiency sewage sludge conditioning-dewatering tehchnology. On the basis of demand for improving the dewaterability of flocculent sludge, this project takes the disruption of key gelation components in hydrogel structure of flocculent sludge as the main line. The following research works will be done: identification of chemical components and structure of key gelation substance in flocculent sludge using advanced characteristics analysis and structural identification techniques; screening the high efficiency enzymes for directional degradation of key gelation substance(some EPS fractions); building the enzymatic directional degradation coupled magnetic field conditioning technology, investigating its conditioning-dewatering efficiency and optimum operation parameters for flocculent sludge, discussing the changes in hydrogel structure, structural heterogeneity, physicohemical characterisitics, EDLVO interaction energy and moisture distribution of flocculent sludge. Furthermore, both the synergistic effect and enhanced mechanisms of the enzymatic directional degradation coupled magnetic field conditioning technology based on the key gelation components will be revealed, the conceptual models for aforementioned process will also be derived as well. The research results of this project will play a fundamental, supporting and inspiration role in the sewage sludge conditioning-dewatering technology, and will enrich its scientific theory and technical reserves. It will promote the development and application of high-efficiency dewatering technology for sewage sludge.

目前，市政污泥的产量随着污水处理率的增加而逐年递增，高效的污泥调理、脱水处理技术的需求极为迫切。本研究基于污水处理厂中絮状污泥脱水性能提升的需要，以絮状污泥水凝胶结构的凝胶化关键物质的破解为主线，采用先进的性质测试与结构鉴定技术，揭示絮状污泥中凝胶化关键EPS组分及其结构；然后根据该EPS组分结构进一步筛选能够定向降解的高效酶，建立定向酶降解-磁场耦合调理技术体系，研究其对絮状污泥的调理脱水效果与最佳操作参数，探讨调理过程中絮状污泥的水凝胶结构、异质性结构、理化性质、EDLVO作用能、水分分布的变化规律，揭示该耦合调理技术的协同效应，明确基于凝胶化关键物质的絮状污泥调理脱水过程的强化机制，抽象出该作用过程的概念模式。上述研究成果可以为污泥调理技术的发展提供基础支撑和技术启发，并丰富污泥调理技术的科学理论和技术储备，从而推动污泥高效脱水技术的发展与应用。

本基金项目主要完成了以下工作：污泥凝胶结构关键物质的识别以及其对污泥水凝胶结构和脱水性能的影响；污泥EPS中关键物质结构与污泥脱水性能的关系；复合酶-化学药剂、单一酶-CTMAB联合调理对污泥脱水性能的影响；活性污泥Mn(Ⅶ)-Fe(Ⅱ)-lysozyme联合调理技术等内容的研究；絮凝调理对污泥水凝胶结构的影响。. 结果表明：Slime、LB-EPS中的水分种类较容易脱除，而TB-EPS和细胞相含有的水分不易脱除。TB-EPS对维持污泥类凝胶结构起着主要的作用，且含有相对较高的结合水含量。PN和PS的水解在一定程度上导致了污泥G0'的减小，降低了污泥的弹性；但污泥类凝胶结构最强，但结构最致密时，脱水效果不一定最好。PN、PS是影响污泥脱水性能的主要EPS组分，slime中聚合链、自由卷曲及β-转角与污泥脱水性能显著相关。TB-EPS中聚合链、β-折叠及β-转角与污泥脱水性能显著相关。适度弱化TB-EPS中聚合物的刚性有利于污泥脱水。EPS的迁移在slime及TB-EPS的蛋白质二级结构形成过程中起到了重要作用，且影响污泥脱水性能的蛋白质二级结构很可能来自于更内层的EPS。 . 复合酶-化学药剂、单一酶-十六烷基三甲基溴化铵(CTMAB)调理污泥时，均能降低CST值和抽滤泥饼含水率。除电中和作用外，CTMAB可通过自身的分散、增溶作用，分散污泥絮体、释放污泥EPS及部分结合水；酶、化学药剂的单一和联合调理均能不同程度地释放污泥颗粒中的束缚水。中温ａ-淀粉酶-CTMAB联合调理释放的污泥结合水最多，其次为中性蛋白酶-CTMAB的联合调理。. Mn(Ⅶ)-Fe(Ⅱ)调理主要氧化EPS，而Mn(Ⅶ)-Fe(Ⅱ)-lysozyme联合调理可以氧化EPS、破解细胞膜；污泥EPS中PN含量在整个调理过程中持续升高；PS在Mn(Ⅶ)-Fe(Ⅱ)阶段上升，而在酶调理阶段下降。TB-EPS层的小分子量和中间分子量物质的峰强降低程度较大，而slime层、LB-EPS则有略微降低。. WD4960调理污泥的渗透压值（绝对值）表明其具有更强向环境释水的趋势，脱水性能更好，提出了遵守“道南平衡”污泥水凝胶结构模型。. 该研究成果可以丰富污泥调理技术的科学理论和技术储备，从而推动污泥高效脱水技术的发展与应用。