| In terms of the present sewage treatment system, most belong to the " energy decontamination", at the same time of sewage treatment need to consume large amounts of energy,as energy shortage and environmental pollution increasing, decontamination and energy consumption is of great importance to solve this contradiction. The emergence of biological electrochemical system (BES) technology to solve this contradiction, the technology mainly include microbial fuel cells and biological electrolytic cell. The technology combines the advantages of biological and electrochemical reaction. Biological electrochemical system mainly includes microbial fuel cell (MFC) technology and microbial electrolysis cell (MEC), the two can not only deal with sewage, as well as recycling energy and clean hydrogen. It can truly achieve the dual efficacy of the "decontamination-capacity". At present, in the organic wastewater pollution, COD emission of molasses wastewater and traditional Chinese medicine wastewater is high, pollution range wide, it is in urgent need of treatment, and from mining, smelting, electrolysis, electroplating, pesticide, medicine, paint, and other enterprises discharge wastewater. Heavy metal sludge and wastewater as fertilizer and irrigation, the soil contaminated, resulting in crop and enter into the water caused by the enrichment of heavy metals in aquatic organisms through the food chain toharm to human body. Based on electrochemical theory of biological knowledge, this study constructed the microbial fuel cells and microbial cells, anode with molasses wastewater and Chinese traditional medicine wastewater as the anode substrate, cathode with metal ions as cathode electron acceptor can be realized。 Cathode double treatment of organic wastewater and molasses wastewater can be realized, but also recycling energy. Based on the MFC with slightly modified for MEC, namely anode for organic wastewater as the anode substrate, applied voltage can realize the combination of electrons and protons to produce hydrogen production. Two stage fermentation of hydrogen production wastewater can be used to produce methane, which can be used to recycle waste,and implement waste reuse.This research first constructs a continuous flow of molasses wastewater as anode and different concentrations of Ag+ as cathode electron acceptor for MFC, thus achieving the stable electricity generation performance and sewage treatment effect, the maximum power density of 62.82 mW·m-2, and the realization of the of Ag+ on the highest removal rate of 71.6%, the maximum COD removal rate was 81.2%. Then the parallel constructs the four groups respectively to Cu2+, Ni2+, Cr6+ and Cd2+, MFC cathode electron acceptor, four groups of MFC anode molasses wastewater COD removal rate can reach more than 70%, the cathode metal removal rate respectively 51%,39%,66% and 48%, and the cathodic reduction products were investigated by XRD analysis, reduction of cathode part product for metal elemental, another part of the oxide. This part of the experiment was successfully constructed continuous microbial fuel cells, and compared with the traditional batch microbial fuel cell. Implement the molasses wastewater treatment process in a row, and recycle energy and metals. On the basis of the above-mentioned study, the optimization of the Ag+ and Cr6+ as cathode electron acceptor, and traditional Chinese medicine wastewater as anode formed continuous flow MFC and achieve a long-term operation, using Ag+as electron acceptor MFC maximum power density is 1165.4mW/m2; maximum coulombic efficiency:8.17%, COD removal rate of 43.47%, the chroma removal rate of 65%. Using Cr6+ as cathode electron acceptor MFC, the maximum power density is 556.38 mW/m2; the maximum coulomb efficiency is 6.06%, the removal rate of COD is 49.26%, the chroma removal rate is 74%. Using 454 high-throughput sequencing analyses MFC anode microbial communities, including hierarchical clustering analysis and doors, classes, genera and species structure were compared. The results show that there are 5 kinds of dominant bacteria in the MFC, of whith Propionibacteriumunclassified and Propionibacteriaceaeunclassified are unknown bacteriaBased on continuous flow MFC, MEC hydrogen production system,which uses herbal medicine wastewater as substrate,has been constructed.Meanwhile,compared to the hydrogen production effect between immobilized sludge and suspended sludge, MEC system with immobilized sludge reach the maximum hydrogen production rate when the organic loading is 24 g COD L-1·d-1.The removal rate of COD of the immobilized system which stabilizes between 43.6% and 50.1% exceeded the removal rate of COD of suspended reactor which stabilizes between 25.8% and 38.9%. HRT is 15h (OLR 4.8 g COD L-1·d-1),which is the best HRT condition when producing methane.The research and the comparation of immobilized sludge and suspended sludge in MEC shows that immobilized sludge system has a more stable and higher production ability.After that,the reseach,in which production of methane using two-stage fermentation process,shows immobilized sludge is markedly helpful to energy recovery.Anode microflorae in MEC are analysed by using the method,454 high-throughput sequencing.As a result,when the MEC system products hydrogen stably, the main dominant bacteria is Acinetobacter_johnsoni which belongs to Acinetobacter and Flavobacterium_denitrificans which belongs to flavobacterium and there are still lots of unknown bacterium. |
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