基于微生物燃料电池的地下水硝酸盐污染原位修复技术及其机理研究

A considerable increase in nitrate concentration in groundwater has seriously affected our drinking water quality and poised potential threats to human health. Developing microbial fuel cells (MFCs) will draw much attention as a promising technology for in-situ remediation of groundwater contaminated by nitrate, which can efficiently perform nitrate removal with concomitant electricity production and avoid a second pollution. However, no technology and mechanism of MFC which is in situ applicable to remediation of groundwater contaminated by nitrate has been proposed so far. This project aims to design MFCs which can in-situ remediate groundwater contaminated by nitrate, optimize the operating parameters and obtain effective nitrate removal and high electricity production. The mechanism for in-situ remediation of groundwater contaminated by nitrate using MFC can be revealed by exploring the effect of electrode potential, redox mediators and different metabolites of nitrate biological removal as electron acceptor, investigating the microbial population, distribution and community succession attached to MFC biocathode. The results will promote theoretical and technological innovations on in-situ remediation of groundwater contaminated by nitrate using MFC.

地下水硝酸盐污染已严重影响我国饮用水安全，对人体健康构成潜在威胁。基于MFC的地下水硝酸盐污染原位修复技术，可去除硝酸盐污染同时产生电能，可避免对地下水无二次污染，将成为前景光明的地下水硝酸盐原位治理技术，但此技术的研究尚未开展。本项目拟创建基于MFC的地下水硝酸盐污染原位修复技术，优化工况参数，获取高效脱氮产电功能；探明电极电势、氧化还原介体、电子受体基质的作用，搞清地下水硝酸盐原位修复MFC阴极生物膜的组成、结构和群落演替规律，有助于揭示MFC对地下水硝酸盐修复机理，有助于推动地下水硝酸盐污染原位修复技术的发展。

地下水硝酸盐污染已严重影响我国饮用水安全，对人体健康构成潜在威胁。地下水硝酸盐生物治理为首选技术，但其存在对地下水造成有机物、微生物等的二次污染问题。基于MFC的地下水硝酸盐污染原位修复技术，可去除硝酸盐污染同时产生电能，可避免对地下水无二次污染，将成为前景光明的地下水硝酸盐原位治理技术。本项目研发了可实现原位修复地下水硝酸盐污染的生物阴极型MFC装置。生物阴极型MFC原位修复地下水硝酸盐污染过程中的最大NO3--N去除负荷达到最高为0.60 gNO3--N/(L•d)，库伦效率达到最大为76%，最大电流密度为4.85A/m2。MFC原位修复硝酸盐污染最佳HRT为12h，最佳外电阻为5Ω，加大地下水电导率至2200µS/cm可进一步提高硝酸盐去除效率至99%。硝酸盐降解速率与硝酸盐初始浓度、电流强度具有很好的相关性，其拟合方程分别为r =74.17×([S]-500)/(1894.03+[S])与r =47.02/(1+1.99/[I]+[I]/158.71)。最佳的硝酸盐降解条件为NO-3-N浓度1500mg/L，电流强度20 μA；电子供体、电子受体均对MFC脱氮性能产生较大影响。建立了反硝化功能微生物富集培养装置（新型厌氧生物反应器）能量耗散模型和不同床层状态下的膨胀模型，阐明了厌氧生物反应器能量耗散特征和床层膨胀特征。