Deciphering the Anode-Enhanced Azo Dye Degradation in Anaerobic Baffled Reactors Integrating With Microbial Fuel Cells

Abstract

Microbial anode respiration in microbial fuel cells (MFCs) can enhance the degradations of many electron acceptor-type contaminants which are presumed to be competitive to anode respiration. The mechanisms underlying those counterintuitive processes are important for MFCs application but are unclear. This study integrated MFCs with anaerobic baffled reactor (ABR), termed MFC-ABR, to enhance the reduction of azo dye acid orange-7 (AO-7). Compare with ABR, MFC-ABR enhanced the degradation of AO-7, especially at high AO-7 concentration (800 mg/L). Acute toxicity test suggested a higher detoxication efficiency in MFC-ABR. Higher microbial viability, dehydrogenase activity and larger sludge granule size were also observed in MFC-ABR. MFC-ABR significantly enriched and reshaped the microbial communities relative to ABR. Bacteria with respiratory versatility, e.g., Pseudomonas, Geobacter, and Shewanella, were significantly enriched. Functional prediction showed that six metabolism functions (manganese-, iron-, fumarate- and nitrate-respiration, oil bioremediation and chemoheterotrophy) were significantly stimulated while methanogenesis, sulfate-respiration, hydrogen-oxidation were suppressed in MFC-ABR relative to ABR. The results provided important information for understanding the role of microbial anode respiration in contaminated environments.

Function-Oriented Graphene Quantum Dots Probe for Single Cell in situ Sorting of Active Microorganisms in Environmental Samples

“…Specialization of the community occurs through the emergence and selection of the most adapted phylotypes, which can be dye-tolerant or decolorizing species ( Yu et al, 2015 ). In polluted environmental samples, bacteria with respiratory versatility are significantly enriched ( Yang et al, 2018 ). Therefore, the estimation of environmental functional microbial populations based on bioimaging will be a new method for rapid preliminary assessment of environmental pollution levels.…”

Recent progress in treatment of dyes wastewater using microbial-electro-Fenton technology

“…Shewanella and Geobacter, 117 were anticipated to be the key players in the improvement of iron respiration. 118,119 Other bacteria with selective relevant function include Serratia, Stenotrophomonas for EET, Stenotrophomonas Dysgonomonas, Brevundimonas, and Achromobacter for reduction of azo-dye or degradation of aromatic compounds. [120][121][122] The relative abundances of fermenters Acinetobacter, Cloacibacillus and methanogens Methanobacterium were lowered under MES systems.…”

Study on Start-Up Membraneless Anaerobic Baffled Reactor Coupled with Microbial Fuel Cell for Dye Wastewater Treatment

“…The decolorization, degradation, and detoxification of azo dyes can be improved by the coupling treatment of azo wastewater with baffled anaerobic reactor and microbial fuel cell (MFC). 17 In addition, the combined approach also shows high stability and impact resistance of carbon felt filler and potential inhibition of the fouling issue in the reactor due to the special structure of the reactor. 18 On the other hand, the utilization of ABR with MFC and a microbial electrolytic cell (MEC) could realize the simultaneous removal of undesirable elements (nitrogen, carbon) and recover energy when treating wastewater.…”

“…The decolorization, degradation, and detoxification of azo dyes can be improved by the coupling treatment of azo wastewater with baffled anaerobic reactor and microbial fuel cell (MFC) . In addition, the combined approach also shows high stability and impact resistance of carbon felt filler and potential inhibition of the fouling issue in the reactor due to the special structure of the reactor .…”