羟胺强化高级氧化对污泥胞外聚合物可控降解与胞外抗性基因协同处理研究

Sewage sludge is difficult to be dewatered due to its high bound water content. The treatment and disposal of sludge is a worldwide problem. How to destroy the highly hydrated nature of extracellular polymer substance (EPS) and emerging contaminants in EPS is the key problem for sludge deep-dewatering. In traditional advanced oxidation process, the accumulation of Fe(III) will greatly reduce the oxidation efficiency, resulting in a decline of the degradation ability for EPS. In this study, hydroxylamine was used to accelerate the Fe(III)/Fe(II) redox cycles. It could adjust the free radicals generation ratio in liquid phase and sludge floc, improving the production and utilization efficiency of free radicals. The mechanism of controllable degradation of EPS was studied by changing the dosage and dose mode of oxidants to produce different concentration of free radicals in the system. Dewatering performance, EPS composition, extracellular polysaccharides and protein structure, surface thermodynamic characteristic, and so on were determined in this study. Competitive reactions of free radicals between the liquid phase and sludge floc would be studied in production mechanism, reaction path, and reaction efficiency. The influence of oxidation intensity on the hydrophilic structure destruction of sludge flocs was clarified, and the law of EPS degradation degree on the release of bound water was explored. The distribution of extracellular antibiotic resistance genes in EPS was determined. The degradation of extracellular antibiotic resistance genes by free radicals in heterogeneous systems was explored.

市政污泥结合水含量高，脱水困难，处理处置是一项世界性难题。如何破解污泥胞外聚合物（EPS）亲水特性以及降解被EPS吸附的新型污染物是影响污泥最终处置的关键问题。传统高级氧化技术中三价铁的积累会大大降低氧化速率，导致其对污泥EPS的降解能力下降。本研究通过外加羟胺促进三价铁/亚铁的循环转化，控制自由基在污泥体系中液/固相的生成比例，提高自由基的产生与利用效率；通过改变氧化剂的投加量与投加方式，在体系中产生不同浓度的自由基，探讨污泥EPS进行可控降解机理。通过测定不同氧化强度预处理污泥的脱水性能、EPS组分、胞外多糖与蛋白质结构、表面热力学特性等特性，研究自由基在污泥液/固相竞争反应中的产生机理、作用路径与反应效率。明确氧化强度对污泥絮体亲水结构破坏影响，探究EPS降解程度对结合水释放的规律。对胞外抗性基因在污泥EPS中的分布进行测定，探究非均相体系中自由基对胞外抗性基因协同降解规律。

污泥是污水处理的副产物，污泥胞外聚合物（EPS）的空间结构与有机物特性是影响污泥脱水性能的关键因素；而脱水污泥的资源化与脱水滤液的生物毒性也是污泥处理处置的重要研究方向。本研究通过羟胺促进三价铁/亚铁的循环转化，通过控制双氧水的投加量，调控体系的氧化强度，实现了污泥EPS的逐层降解。但是污泥脱水性能随着EPS内层亲水性多糖的暴露，增加污泥絮体水合作用能，进而导致污泥絮体间能垒的增加，脱水性能恶化。此外，开发了酸洗预处理技术，使厌氧消化污泥减量，同时提高了其土地利用性。深度脱水污泥的资源化利用与脱水滤液污水处理厂原位处理也进行了研究。