电场调控的颗粒态Fe-S2O82-非均相氧化体系调理污泥的性能与生物颗粒的电化学特征研究

Along with the rapid development of economy, society and urbanization of our country, massive excess sludge has been produced in wastewater treatment plants. In order to reduce the volume of the excess sludge and its environmental impact, high-efficiency technology for its conditioning-dewatering is becoming a key and hot point to realize the aforementioned goals. In this applied project, on the basis of the novel sludge conditioning technology-particulate Fe activated S2O82- heterogeneous oxidation system, the topic ‘the performance of conditioning excess sludge with electric field regulated and controlled particulate Fe-S2O82- heterogeneous oxidation system and the corresponding electrochemical characteristics of biosolids’ was proposed. During the sludge conditioning process with this heterogeneous oxidation system, the variations of sludge composition and physicochemical properties, EPS components, flocs characteristics, dewaterability and correlations between rheological and electrochemical characteristics of biosolids under different operational conditions will be studied. The optimum operational conditions for this heterogeneous oxidation system will be determined, as well as the synergistic effect between electric field and particulate Fe-S2O82- on the improvement of excess sludge dewaterability. Through building the correlation between rheological and electrochemical characteristics of excess sludge, the correlated feature between the macro-structure and micro-structure of these biosolids will be identified, and the corresponding implications of mechanics and physicochemistry for gel-like structure of the biosolids will also be exposed. Finally, the mechanisms and strategy of electric filed regulation and control on the excess sludge conditioning with particulate Fe-S2O82- heterogeneous oxidation system will be confirmed.

随着我国经济、社会以及城镇化的高速发展，污水处理厂产生了大量的剩余污泥。为了实现污泥的减量化，降低其环境影响，高效的污泥调理脱水技术成为完成该目标的关键和热点。该申请项目以颗粒态Fe为激发材料的S2O82-非均相氧化体系调理污泥的新技术为出发点，提出研究颗粒态Fe-S2O82-非均相氧化调理污泥性能的电场调控与生物颗粒的电化学特征的主题。通过研究上述非均相氧化体系不同调理条件下污泥的组成、理化性质、EPS组分、絮体特征、脱水性能以及流变学与电化学特征相关性等变化，优化出电场调控的颗粒态Fe-S2O82-氧化体系调理污泥技术的最佳操作条件，确定该耦合调理技术对污泥脱水性能提高的协同效应，建立上述调理过程中污泥流变学与电化学特征的相关性，识别生物颗粒的宏观结构与微观结构之间的关联特征，解析其类凝胶结构的机械力学与物理化学内涵，明确电场对颗粒态Fe-S2O82-氧化体系调理过程的调控机制和策略。

提出了活性污泥Mn(Ⅲ)氧化调理、颗粒态Fe/persulfate氧化调理方法，证明了这些方法对污泥减量的有效性，解析了调理-电脱水工艺的作用机制。.在Mn(Ⅲ)C–HED 作用过程中，总的水分含量、自由水含量、结合水含量的下降率分别为 85.86%、87.62%、51.68%（阳 极），82.64%、85.08%、36.55%（阴极）。污泥的体积显著减小。Mn(Ⅲ)的氧化作用导致污泥细胞破碎和EPS 的解体以及部分结合水释放，促进内层 EPS 向外层转化，有利于污泥脱水。此外，Mn2+通过与污泥中微生物细胞上的大分子物质结合，对污泥起到了絮凝作用。在水平电场作用下，污泥细胞进一步破解，更多的结合水转化为自由水被去除。而生成的 MnO2 颗粒，可以作为骨架支撑材料，使污泥呈现多孔的结构，提供水分去除的通道。.在ZVI/PS-HED工艺中，经过 30 min 氧化调理和2 h 水平电场脱水（40 V）后，污泥中自由水和束缚水的去除率分别为 96.4%和79.7%，污泥含水率由 98.62%降至 83.67%。氧化调理阶段中，SO4-·氧化导致一部分结合水转化为自由水，污泥中 Fe2+氧化成 Fe3 +的混凝作用抵消了污泥絮体的氧化破解，有利于电渗脱水通道的形成。此外，由于氧化降解，液相和固相中的蛋白质和多糖含量降低，且整个工艺对污泥黏液层 EPS（slime）影响显著， 其 EPS 含量的降低有利于提升污泥脱水性能。.Siderite / PMS-PEOD工艺中，Siderite / PMS反应产生SO4-·和HO·可以分解EPS、破解絮体，在碎片之间出现明显的孔道，污泥中束缚水降低了25.23%，经过PEOD处理后，污泥束缚水降低了91.76%。EPS中蛋白质二级结构α-helix/(β-sheet + random coil)比值的变化表明氧化调理导致更加致密的TB-EPS结构和更加疏松的slime结构；证明了典型氨基酸与污泥脱水能力的相关性，提出了疏水性氨基酸Ala与亲水性氨基酸Lys的比值(Ala/Lys)指示蛋白质持水能力，Siderite-PMS体系调理破坏了slime和TB-EPS中蛋白质的持水能力，Ala /Lys与污泥脱水能力明显负相关，调理后污泥中Ala与水的接触数显着减少，水分从TB-EPS和LB-EPS层迁移到slime层。