单室空气阴极微生物燃料电池硝酸根去除系统的建立和性能研究

本文以单室空气阴极微生物燃料电池(Microbial Fuel Cell,MFC)处理含不同浓度硝酸根的模拟废水,研究了NO~-_3-N初始浓度和开闭路培养方式对单室MFC的启动、硝酸根去除性能和产电性能的影响.结果表明,随着NO~-_3-N初始浓度的提高,MFC的NO~-_3-N平均去除速率达到稳定值所需时间增加,NO~-_3-N平均去除速率提高.当NO~-_3-N初始浓度为200 mg·L~(-1)时,闭路组MFC的NO~-_3-N平均去除速率达到(3.52±0.28) kg·m~(-3)·d~(-1),高于相近条件下许多传统生物反应器的NO~-_3-N平均去除速率.硝酸根去除过程主要发生在MFC运行周期的前期.硝酸根对阳极生物膜中主要产电菌Geobacter的生物量没有影响.当基质充足时,所有闭路组MFC的最大功率密度相近(～27 W·m~(-3)).闭路组MFC比开路组MFC具有更高的NO~-_3-N去除速率,可能与其阳极生物膜具有电化学还原亚硝酸根能力和Thauera易在其阳极上富集有关.

Development and performance of single-chamber microbial fuel cell denitrification systems

Single-chamber air cathode microbial fuel cells (MFCs) were constructed to treat synthetic wastewater containing different concentrations of nitrate. The start-up, nitrate removal and electricity generation of single-chamber MFCs were investigated under closed-circuit (closed-circuit MFCs) or open-circuit (open-circuit MFCs) operation. It is found that increasing initial NO₃^--N concentration extended the time required for the MFCs to obtain the stable average NO₃^--N removal rate, but enhanced the average NO₃^--N removal rate. When the initial NO₃^--N concentration was 200 mg·L^-1, the average NO₃^--N removal rate of the closed-circuit MFCs was up to (3.52±0.28) kg·m^-3·d^-1, which was higher than those of many traditional biological denitrification systems under similar conditions. Nitrate was reduced at the early stage of a cycle in the MFCs. The biomass of the dominant exoelectrogen Geobacter enriched at the anodes in the closed-circuit MFCs was not affected by nitrate. With sufficient substrate, the maximum power densities of all the closed-circuit MFCs were similar (~27 W·m^-3). The NO₃^--N removal rate of the closed-circuit MFCs was higher than that of the open-circuit MFCs, which was probably attributed to the anode biofilm with characteristics of bioelectrochemical reduction of nitrite and high enrichment of Thauera in the closed-circuit MFCs.