生物电化学强化含氯代硝基苯类有机废水厌氧生物处理的机理研究

The integrating process of chemical redox and biodegradation is a key technology for efficient treatment of toxic refractory organic wastewater and remediation of persistent organic pollutants. In this project, chlorinated nitrobenzens containning wastewater are chosen as object, and a novel process of anaerobic sludge reactor coupled with bioelectrode is established in view of the characteristics of anaerobic microbial reductive dechlorination and biological electrochemical catalytic reduction. The coordinated reductive dechlorination of chlorinated nitrobenzens with bioelectrode and anaerobic sludge, and process performances of anaerobic sludge reactor coupled with bioelectrode would be studied. At the same time, the characteristic ,microbial population succession of electrode biofilm formation and anaerobic sludge granulation would also be investigated. On these basis, the mechanism of enhanced performances of novel process of anaerobic sludge reactor coupled with bioelectrode for treatment of chlorinated nitrobenzens containning wastewater would be demonstrated according to the biocathode as electron donor, enhanced anaerobic sludge granulation and reductive dechlorination transformation , and microbial molecular ecology. The research not only has important academic value, but also provides the innovative integrating technological principle for toxic refractory organic wastewater treatment and contaminated environmental bioremediation.

化学氧化还原与生物处理工艺集成是有毒难降解有机废水高效处理、持久性有机污染物控制与修复的关键技术。项目基于厌氧微生物的还原脱氯特性与生物电化学催化性能，创新构建生物电极与厌氧生物反应器耦合工艺，以含氯代硝基苯类工业有机废水为对象，研究电极与厌氧污泥协同还原脱氯转化氯代硝基苯类污染物特性、耦合工艺运行性能、电极生物膜形成与厌氧污泥颗粒化，及其微生物菌群结构演替规律。从生物阴极电子供体作用、强化厌氧污泥颗粒化与污染物还原脱氯转化、功能菌群微生物分子生态等角度，阐明生物电极与厌氧污泥耦合强化氯代硝基苯类有机废水厌氧生物处理的机理。这不仅具有重要的学术理论价值，而且可为有毒难降解有机废水高效处理、污染环境生物修复提供创新的集成技术原理。

卤代芳香烃、含氯含硝基芳烃等属于典型持久性有机污染物。生物电化学系统（BES）是近年来国内外多学科多领域关注的热点，探索生物电化学辅助厌氧生物处理工艺高效去除持久性有毒有机物污染有重要科学意义与潜在应用价值。. 项目创新构建了生物电极与厌氧污泥耦合工艺，以含氯代硝基苯类有机废水为对象，开展电极与厌氧污泥协同还原脱氯转化氯代硝基苯类污染物特性、耦合工艺运行性能、电极生物膜形成与厌氧污泥颗粒化及其微生物菌群结构演替规律等研究。结果表明，合适的外加电压（0.5-0.75V）条件下对氯代硝基苯（p-ClNB）、2,4-二氯代硝基苯（2,4-DClNB）等氯代硝基苯类污染物还原转化以及中间代谢产物脱氯速率，维持较低的阴极电势-630~-690mV有利于中间产物氯苯胺类（ClAn）还原脱氯生成苯胺（An），揭示了生物电极与厌氧污泥耦合体系还原脱氯转化氯代硝基苯类污染物的协同效应。在反应器水平上开展了生物电极-厌氧污泥耦合工艺的性能与过程调控研究，发现有机负荷、电极电势、电极位置等工艺参数对目标污染物处理性能影响显著，电子供体不足条件下生物电极通过提高电子利用率实现含氯含硝基芳烃稳定脱氯，电极位置适当抬升可促进中间产物ClAn进一步脱氯形成苯胺（An），纳米磁铁矿通过强化电子传递与利用，进一步提升耦合工艺有机物去除与ClAn脱氯性能；间歇加电运行在控制能耗同时强化目标污染物还原转化。应用荧光染色、高通量测序等技术，发现生物电极生物膜表层与中间层（0-40μm）分布大量的活性导电细胞，耦合工艺污泥分泌大量EPS（尤其是芳香族类蛋白）有利于电极生物膜与颗粒污泥形成以及功能菌的发育与定殖，改善厌氧颗粒污泥品质与活性，电极生物膜与颗粒污泥高度富集Geobacter、Dehalobacter、Dehalococcoides等具有电子传递与脱氯有关的功能菌群，以此为基础从生物阴极电子供体、功能菌群分子生态等角度，提出了生物电极与厌氧污泥耦合工艺强化氯代硝基苯类有机废水厌氧生物处理的过程机制。研究成果为有毒难降解有机废水高效厌氧处理新技术开发提供创新的技术原理。