连续搅拌微生物电化学系统处理高浓度模拟废水的效能

Performance of a continuous stirred microbial electrochemical reactor treating high-strength artificial wastewater

摘要:

微生物电化学系统在面向实际废水处理时, 表现出产电性能下降、出水水质差等缺点.为了提高其处理中高浓度、含发酵类底物废水的性能, 将连续搅拌釜式反应器与之耦合, 构建一体式连续搅拌微生物电化学系统(CSMER).确定系统的最佳运行条件：以连续流方式运行, 在水力停留时间为12 h, 进水COD浓度为6 000 mg·L^-1时, 系统内4个电池的最大功率密度分别达(583±9), (562±7), (533±10) 和(572±6) mW·m^-2, COD去除率为(87.1±1.1)%, 甲烷产率为(1.48±0.15) L·L^-1·d^-1.与对照的连续搅拌釜式反应器相比, 其COD去除率及甲烷产率分别提高了61.6%及244.2%.焦磷酸测序结果表明, CSMER底端的全混流搅拌区(CMZ)以Clostridium(10.0%)、Acidaminococcus(11.7%)及Lactococcus(10.8%)等水解发酵菌群为优势细菌菌属；顶端的微生物电化学区(MEZ)以产电菌Geobacter(14.5%)占优势.CSMER中相对复杂的细菌群落结构使其同时含有丰度较高的嗜乙酸产甲烷菌科(52.2%)和嗜氢产甲烷菌科(47.1%), 而底端CMZ的厌氧消化过程与顶端MEZ的产电过程之间的协同作用是实现该系统性能优于对照反应器的主要原因.

Abstract:

Microbial electrochemical systems (MESs) suffer deterioration in power generation and wastewater treatment in practical application. In order to improve the performance of MESs when treating medium and high strength wastewater containing fermentative substrates, a continuous stirred microbial electrochemical reactor (CSMER) was developed by integrating MES and continuous stirred tank reactor (CSTR). Maximum power densities of (583±9), (562±7), (533±10) and (572±6) mW·m^-2 were obtained by each separate cell of CSMER under continuous feeding mode (HRT=12 h) at COD concentration of 6 000 mg·L^-1. COD removal and methane production rate of CSMER were (87.1±1.1)% and (1.48±0.15) L·L^-1·d^-1, which increased by 61.6% and 244.2% in comparison with those of a control CSTR. Pyrosequencing analysis showed that the dominant genera in CSMER_CMZ were Clostridium (10.0%), Acidaminococcus (11.7%) and Lactococcus (10.8%), which were fermentative bacteria. The microbial electrochemical zone (MEZ) was dominated by Geobacter (14.5%), which was the most predominant known exoelectrogen. Due to the relatively complicated bacterial communities, the CSMER possessed high abundance both in acetoclastic methanogens (52.2%) and hydrogenotrophic methanogens (47.1%). Syntrophic process occurred between anaerobic digestion in the CMZ and current generation in the MEZ contributed to its better performance.