Pesticide contaminants, such as chlorpyrifos (CP) and its more toxic metabolite 3,5,6-trichloro-2-pyridinol (TCP) in farmland drainage have attracted extensive concerns around the world, and are in urgent need of treatment. In this work, three groups of anaerobic reactors packed with zero valent iron (mono-ZVI system), ZVI coupled with anaerobic sludge (coupled system) and anaerobic sludge (mono-cell system) were continuously operated to investigate their performances on CP, TCP and chemical oxygen demand (COD) removal, as well as the reaction mechanisms of ZVI coupling with anaerobic microorganisms. Results showed that the removal efficiencies of CP and COD in coupled system were both around 95%. The corresponding results were 80% and 82% in mono-cell system, and the unstable values in mono-ZVI system were around 86% and 70%. The TCP residual concentration was the lowest in coupled system. The results of X-ray photoelectron spectrometer (XPS) and the photo images of ZVI at the end of reaction implied that the presence of sludge and the interaction between microorganisms and ZVI protected iron shavings from excessive corrosion. Moreover, the addition of ZVI promoted the electron transfer in the anaerobic system, which was proved by the higher value of electron transport system (ETS) activity and Cytochrome C (Cyt C) content of sludge with 250 mg (g h)⁻¹ and 20.71 nmol L⁻¹ in coupled system, compared to 200 mg (g h)⁻¹ and 17.56 nmol L⁻¹ in mono-cell system. The improvement of extracellular polymeric substances (EPS) and anaerobic sludge granulation in the coupled system were on account of the existence of ZVI. It was obvious that the key enzymes and microbial species functioned in COD, CP and TCP degradation were enriched in coupled system.

农田排水中的农药污染物，如毒死and（CP）及其毒性更高的代谢物3,5,6-三氯-2-吡啶醇（TCP），引起了世界范围的广泛关注，迫切需要治疗。在这项工作中，连续运行三组装有零价铁的厌氧反应器（单ZVI系统），ZVI与厌氧污泥（耦合系统）和厌氧污泥（单电池系统），以研究其在CP，TCP上的性能化学需氧量（COD）的去除以及ZVI与厌氧微生物的反应机理。结果表明，耦合系统中CP和COD的去除率均在95％左右。在单电池系统中，相应的结果分别为80％和82％，在单ZVI系统中的不稳定值大约为86％和70％。TCP残留浓度在耦合系统中最低。X射线光电子能谱仪（XPS）的结果和反应结束时ZVI的照片图像表明，污泥的存在以及微生物与ZVI之间的相互作用可保护铁屑免于过度腐蚀。此外，ZVI的添加促进了厌氧系统中的电子转移，这通过更高的电子传输系统（ETS）活性和细胞色素值来证明。耦合系统中具有250 mg（g h）^-1和20.71 nmol L ^-1的污泥的C（Cyt C）含量，而单电池系统中为200 mg（g h）^-1和17.56 nmol L ^-1的污泥的C（Cyt C）含量。偶联体系中细胞外聚合物（EPS）和厌氧污泥颗粒化的改善归因于ZVI的存在。显然，在耦合系统中，在COD，CP和TCP降解中起作用的关键酶和微生物种类丰富了。