| SMFC is a new method by using electricity bacteria who can obtain electricity and from the substrate to remove contaminants,which is also the most direct way to recover energy from litter or waste water.Its anode buried in sediments using humus,sulfide and other reductive pollutants in sediments as an electron donor and its cathode was in the overlying water,which can use the nitrate,perchlorate,heavy metal ions and other oxidizing pollutants as electronic receptors.The particularity of this structure and the new pattern of reactivity make it possible to achieve simultaneous bioremediation of sediments and overlying water and produce electrical energy meanwhile.Besides,its mobility was strong and can be used in rivers,lakes and other natural water without external electron donors or receptors.So it has a great application prospects.However,the practical application of SMFC need to overcome some shortcomings such as unstable performance low output power.In this paper,the SMFC system was constructed by using the sediment the ultrapure water to explore the effects of different DO concentrations on the nitrogen transport and transformation and the production performance of the SMFC system.The main experimental contents and results are as follows:(1)The SMFC system was constructed by using sediments and water in the black-odor river to achieve the enrichment of the electricity producing bacteria..It was found that the voltage reached the stability at 320 hSMFC system,and the enrichment of the electricity producing bacteria was successful.(2)The effects of different DO concentrations on TN removal efficiency in SMFC system were investigated.The results showed that the cumulative removal rate of TN was the highest at 60.55% under the condition of DO=3mg/L,and the least at 38.35% when DO=8mg/L.it is not conducive to SMFC removal of nitrogen when DO concentration is too high or too low.(3)The effects of different DO concentrations on LOI removal efficiency of SMFC sediments were investigated.The results showed that the removal rate of LOI was the highest at 33.4% under the condition of DO=8mg/L,and the lowest LOI removal rate was 12.3% when DO=0mg/L.DO concentration is positively correlated with the LOI removal rate of sediments which means the higher the DO concentration,the more favorable the degradation of organic matter in sediments.(4)The effects of different DO concentrations on the migration and transformation of nitrogen in SMFC system were investigated.The results showed that DO concentration had a great effect on the migration and transformation of nitrogen in the SMFC system.the removal of nitrogen in the SMFC system was mainly anaerobic ammonium oxidation and secondly electrochemical reduction,under the condition of DO=0mg/L.The nitrogen removal pathway in the SMFC system was electrochemical reduction and short nitrification and denitrification when DO=1mg/L.The removal of nitrogen in SMFC system was mainly due to electrochemical reduction and simultaneous nitrification and denitrification in the presence of DO=3mg/L.The removal of nitrogen in SMFC system was mainly due to simultaneous nitrification and denitrification and secondly the electrochemical reduction when DO=5mg/L.(5)The effects of different DO concentrations on the electricity production performance of SMFC system were investigated.The results showed that the output voltage,current density and power density of the SMFC system were increasing with the increase of the DO concentration,and the DO concentration was the main factor that influenced the cathode Potential.In this paper,the influence of different DO concentration on the migration and transformation of nitrogen and the influence of the power generation performance in the SMFC system were studied,which had important academic and provided significance theoretical support for the practical application of SMFC as the technology of in situ repair and recovery of electrical energy. |
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