双室微生物燃料电池处含银废水的产电性研究

以剩余污泥为阳极底,糖蜜废水为基质,Ag Cl废水为阴极电子受体,构建了双室微生物燃料电池(Two-chamber Microbial Fuel Cell,简称MFCs),并研究了电池的产电特性、库仑效率及金属去除率.结果表明:Ag+不仅可以作为阴极电子受体,而且还能稳定产电,外电阻为1000Ω时,获得的最大电压为514.5 m V,最大功率密度为65.82 m W·m-2.在阴极实现了对废水中Ag+的去除,最大去除率可达71.6%,而且Ag+浓度为2000 mg·L-1时,回收金属银单质质量为197.66 g.在阳极对废水的处理效果也很显著,库仑效率最高为2.66%,COD去除率最大为81.22%.     

不同阳极设置对人工湿地-微生物燃料电池脱氮及产能的影响

人工湿地-微生物燃料电池（constructed wetland-microbial fuel cell, CW-MFC）耦合系统是人工湿地和生物电化学技术的有机结合,其中阳极是限制耦合系统输出功率和污染物净化性能的关键因素。构建了未加入颗粒活性炭（CW-MFC1）和加入颗粒活性炭（CW-MFC2）2套耦合系统以探讨阳极加入颗粒活性炭对耦合系统产电和脱氮性能的影响,并利用高通量测序技术对比分析2套系统阳极和阴极微生物群落组成。结果表明：CW-MFC2耦合系统的输出电压和最大功率密度（430 mV,8.39 mW/m²）高于CW-MFC1（379 mV,7.77 mW/m²）。试验运行前期（0 ~29 d）,CW-MFC2耦合系统的氨氮去除率为65.72%±3.06%,显著高于CW-MFC1（56.06%±3.71%）,而二者的总氮去除率相差不大;随着时间的推移（30 ~105 d）,CW-MFC1耦合系统的氨氮和总氮去除率逐渐高于CW-MFC2,尤其是总氮去除更为显著（CW-MFC1为42.69%±4.19%,CW-MFC2为32.50%±11.51%）。高通量测序结果表明,CW-MFC1阳极富集的不动杆菌属以及阴极大量的反硝化菌（巨大芽殖杆菌属、地杆菌属、黄杆菌属、不动杆菌属和脱氯单胞菌属等）的富集可能是其脱氮性能优于CW-MFC2的主要原因。综上,阳极加入颗粒活性炭可提升CW-MFC耦合系统的产电性能,但不利于生物脱氮过程。

     

Performance evaluation of microbial fuel cell for landfill leachate treatment: Research updates and synergistic effects of hybrid systems

Over half of century, sanitary landfill was and is still the most economical treatment strategy for solid waste disposal, but the environmental risks associated with the leachate have brought attention of scientists for its proper treatment to avoid surface and ground water deterioration. Most of the treatment technologies are energy-negative and cost intensive processes, which are unable to meet current environmental regulations. There are continuous demands of alternatives concomitant with pos...     

Biofilm response and removal via the coupling of visible-light-driven photocatalysis and biodegradation in an environment of sulfamethoxazole and Cr(VI)

The widespread contamination of water systems with antibiotics and heavy metals has gained much attention. Intimately coupled visible -light-responsive photocatalysis and biodegradation (ICPB) provides a novel approach for removing such mixed pollutants. In ICPB, the photocatalysis products are biodegraded by a protected biofilm, leading to the mineralization of refractory organics. In the present study, the ICPB approach exhibited excellent photocatalytic activity and biodegradation, providing up to ∼1.27 times the degradation rate of sulfamethoxazole (SMX) and 1.16 times the Cr(VI) reduction rate of visible-light-induced photocatalysis . Three-dimensional fluorescence analysis demonstrated the synergistic ICPB effects of photocatalysis and biodegradation for removing SMX and reducing Cr(VI). In addition, the toxicity of the SMX intermediates and Cr(VI) in the ICPB process significantly decreased. The use of MoS₂/CoS₂ photocatalyst accelerated the separation of electrons and holes, with•O₂^– and h⁺ attacking SMX and e^– reducing Cr(VI), providing an effective means for enhancing the removal and mineralization of these mixed pollutants via the ICPB technique. The microbial community results demonstrate that bacteria that are conducive to pollutant removal are were enriched by the acclimation and ICPB operation processes, thus significantly improving the performance of the ICPB system.     

Performance of a water hyacinth （Eichhornia crassipes） system in the treatment of wastewater from a duck farm and the effects of using water hyacinth as duck feed

Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 m2 was constructed on an egg duck farm, and water hyacinth (Eichhornia crassipes) was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks’ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand (COD), 21.78% of total nitrogen (TN) and 23.02% of total phosphorus (TP). Both dissolved oxygen (DO) and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the di erences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group (P < 0.05), but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth.We concluded that a water hyacinth system was e ective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.