剩余污泥醌呼吸偶联重金属还原脱毒作用研究

The toxicity of heavy metal is the most important limiting factor in the reuse of excess sludge. Based on the metabolic pathways and the principle of the anaerobic quinone respiration, coupled with degradation of organic matter and heavy metals reduction, the method is applied for anaerobic sludge digestion synchronized with the reduction of heavy metals. It is to say that the quinine respiration of sludge will be enhanced to realize the reduction of heavy metals along with the methane production at the same time. The stabilization and harmlessness of excess sludge will thus be achieved. This research focuses on the key problem of anaerobic quinone respiration for heavy metals reduction which has not been explored. The condition of anaerobic quinone respiration and detoxification by heavy metals reduction will be deeply studied. According to the characterization and analysis of humic acid structure, the relationship among its structure - chemical properties - quinone respiration activity will be established. The related mechanism of humic acids as the electronic shuttle vector will also be investigated in this project. This research will provide technical and theoretical support to build and control the high-efficient anaerobic digestion quinone respiration system. The benefits of this project will not only promote the research of the excess sludge stabilization and heavy metals but also help understand the basic question, the relevant law and mechanism of heavy metal reduction by the microbial quinone respiration which provides a reference of the key issues in a number of scientific fields.

重金属的毒性是剩余污泥再利用的最主要限制因素。申请者基于厌氧醌呼吸偶联有机物降解和重金属还原的代谢途径及原理，提出污泥厌氧消化同步醌呼吸还原重金属的新思路，即在污泥消化产甲烷的同时，强化污泥的醌呼吸作用，使重金属得到还原，进而实现剩余污泥的减量稳定和重金属的无害化。本研究将针对尚未被探索的厌氧醌呼吸还原重金属过程的关键问题，深入的开展醌呼吸构建条件、还原重金属脱毒作用及规律的研究，并通过对腐殖质结构及与金属结合特性的表征和分析，建立其结构-化学特性-醌呼吸活性的关联关系，深化腐殖质作为有机物和重金属电子穿梭载体的相关机制，为构建和控制高效厌氧消化醌呼吸还原重金属脱毒系统及深入相关机理提供技术支持和理论依据。本项目的实施，不仅有利于推进剩余污泥的稳定、重金属脱毒及再利用的研究，还有助于了解微生物醌呼吸这一新型代谢途径的基本规律和机理，为解决一些科学领域的关键问题提供参考。

本项目研究了厌氧污泥醌呼吸作用以及降解氯酚类有毒物质的特性、影响因素及机理。利用蒽醌-2,6-双磺酸为模式物在厌氧消化过程富集醌呼吸微生物，结果发现，富集产物具有较强的腐殖质还原能力。不同来源的腐殖质因其具有不同的分子结构和醌功能基团数量，对污泥的醌呼吸的促进作用有所差别。而可从还原性腐殖质接受电子的Fe(III)可显著加强醌呼吸速率。富集产物以有机物作为电子供体时可偶联转化苯和三氯乙烯等环境有毒物质。研究中以脱氯微生物为代表对醌呼吸相关微生物在厌氧污泥中的作用进行了考察，以氯酚为加富培养物获得脱氯厌氧污泥，明确了环境因子(ORP、pH、碱度、硝酸盐、硫酸盐、抗生素等)对还原脱氯的影响，并考察了脱氯污泥的醌呼吸特性。驯化培养物通过现代分析技术——高通量测序对脱氯微生物的种属等生物信息进行测定，分析了脱氯污泥的种群组成、聚类分析、动态演变等信息。结果表明，在氯酚的胁迫下，污泥内的微生物多样性减少，脱氯污泥中产氢产乙酸菌占有绝对优势，产氢产乙酸菌并不脱氯，但是和脱氯菌互营共生，起到释氢作用，因此是实现微生物胞外电子传递（醌呼吸）的关键环节，是醌呼吸微生物的重要伴生菌。本研究深入了厌氧醌呼吸机理及相关微生物的特性、基本问题、相关规律，有利于推进剩余污泥的稳定、脱毒及再利用的研究，深入了微生物醌呼吸这一新代谢途径的机理，为探讨该类微生物在环境物质循环过程中的相关科学问题及对有毒物质的降解提供理论基础。