| Refinery wastewater is a special kind of sewage that is generated from petroleumrefining industry. It contains a large amount of bio-hazardous petrochemical pollutants,and the discharge of which increases annually along with the development of petroleumindustry. In traditional refinery wastewater treatment process, huge energy is consumed,and during the biological oxidation process, a lot of energy generated from which isdissipated as heat, can not realize recovery utilization. Therefor it can not fulfill thedevelopment needs of particular times.Microbial fuel cell (MFC) can directly transform chemical energy into electricitysimultaneously with wastewater treatment, therefor in this study, refinery wastewaterwas used as fuel to construct MFCs to explore the feasibility of using MFC technologyto treat refinery wastewater and recovered the chemical energy stored in it. On this basis,the influence of each structure and operating parameters on the performances of MFCswas investigated in the general, the community structure of dominant microorganismsthat enriched in anode was analyzed, and the microbial synergic and antagonistic effectin refinery wastewater MFCs was detected using these single pure dominantmicroorganisms which were isolated from the anode chamber of refinery wastewaterMFC. The electron transfer mechanism in different MFCs was preliminarily discussedalso. These research results primarily contain several aspects:(1) Refinery wastewater could be used as fuel to generate electricity both insingle-chambered MFC and double-chambered MFC, and the electricity generation andwastewater treatment performances of double-chambered MFC was obviously betterthan single-chambered MFC, the highest voltage output could reach268mV and the oilpollutants removal rate could reach81.8±3%. However the columbic efficiency ofrefinery wastewater MFC was low, only could reach2.5%-3.0%.(2) Except cathode area, the other impact factors such as inoculum, externalresistance, anode conductivity, pH, buffer intensity, anolyte concentration, catholyteconcentration and catholyte kinds all could affect the electricity generation performanceof refinery wastewater MFC. In order to realize better electricity generationperformance, higher external resistance, anode conductivity, buffer intensity, anolyte concentration, catholyte concentration and slightly alkaline pH were needed.(3) The characteristics of packing materials could seriously impact the electricitygeneration and wastewater treatment performances of refinery wastewater MFC. Withbetter electrical conductivity, the electricity generation performance was better (305mV), the ohmic resistance was lower (446Ω), the microbial community diversityenriched in anode was higher, the anode polarization phenomenon was weaker and thewastewater treatment efficiency was better. With better adsorbability, the apparentinternal resistance was lower (957Ω) and the stability of MFC was better. Thecharacteristics of packing materials could directly impact the petroleum pollutantsdegradation rules in MFCs, when MFC was not packed with any material, alkylhydrocarbon were degraded prior, however when MFC was packed with materialswhich had nice adsorbability, aromatic hydrocarbon and volatile phenols were degradedprior. In graphite granule packed MFC, electrons generated from microbial metabolismprocess were transferred to electrode by graphite granule, however in activated carbongranule packed MFC, because of the bad electrical conductivity of the packing materials,microorganisms could derive nanowire forming net structure to transfer electrons.(4) In refinery wastewater MFC, microbial synergisticand antagonistic effectindeed exist among Microbacterium sp., Paenibacillus sp. and Deinococcus sp.Synergistic effect was observed between Paenibacillus sp. and Deinococcus sp., andMicrobacterium sp. exhibited an antagonistic effect against Paenibacillus sp. andDeinococcus sp. The antagonistic effect to Paenibacillus sp. was obviously stronger.Further on, the antagonistic effect generated from Microbacterium sp. was evidentlystronger than the synergistic effect existed between Paenibacillus sp. and Deinococcussp. The cause for this phenomenon was the metabolic function of different microbialstrains to petroleum pollutants was different. |
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