电导率对厌氧产酸、正渗透与微生物燃料电池耦合工艺运行性能的影响

Effects of Conductivity on Performance of a Combined System of Anaerobic Acidification,Forward Osmosis,and a Microbial Fuel Cell

将厌氧产酸(AA)、正渗透技术(FO)与微生物燃料电池(MFC)进行耦合,构建了用于污水处理的AAFO-MFC耦合工艺,实现污水的同步产电和回用.由于电导率是AAFO-MFC运行的关键因素,考察了电导率对系统运行性能的影响.结果表明,较高的电导率可以降低MFC的内阻,提高产电,但是会加重FO膜污染,导致FO膜通量快速衰减,缩短运行时间.电导率对出水水质并没有显著影响,FO膜出水的总有机碳(TOC)和总磷(TP)浓度分别低于4 mg·L^(-1)和0.5 mg·L^(-1),但是FO膜对于氨氮(NH+4-N)的截留效果较差.控制反应器内电导率为7~8 m S·cm-1时,系统整体性能表现最佳,可以获得连续且相对稳定的输出电压,而且FO膜通量下降较为缓慢,运行周期达到29 d.

In this study,a novel combined system for simultaneous recovery of bioelectricity and water from wastewater was developed by integrating anaerobic acidification and a forward osmosis（ FO） membrane with a microbial fuel cell（ AAFO-MFC）. Conductivity was thought to be an important factor affecting the performance of the AAFO-MFC system. Thus,effects of conductivity on the performance of AAFO-MFC system in treating synthetic wastewater were investigated. The results indicated that a higher conductivity increased the bioelectricity production,owing to a reduction in the internal resistance. However,it resulted in a rapid decrease of FO water flux and a shorter operating time because of a severer membrane fouling. The conductivity had no impact on the water quality of the effluents. The total organic carbon（ TOC） and total phosphorus（ TP） concentrations in the FO permeate were less than 4 and 0. 5 mg·L^-1,respectively,at all conductivity levels. However,the rejection of the FO membrane for NH＋4-N was lower at all conductivity levels. The optimal comprehensive performance of this system was obtained when the conductivity was maintained at 7-8 m S·cm^-1. In this case,the AAFO-MFC system achieved continuous and relatively stable power generation,and the water flux of FO membrane was relatively stable during a long-term operation of approximately 29 days.