| Under mild conditions,microorganisms produce hydrogen through the metabolism of organic matter,which has the advantages of low hydrogen production cost and no secondary pollution,and is one of the research hotspots of new energy sources.At present,the hydrogen production efficiency of the dark fermentation biological hydrogen production technology is relatively low,and the means for promoting hydrogen production are mostly focused on the optimization of the reaction conditions and the improvement of the reactor form.Electric stimulation can promote the growth and metabolism of microorganisms;the bipolar membrane electrodialysis coupled fermentation hydrogen production process can timely separate acetic acid in the fermentation broth,remove product inhibition,and regulate the system p H.Therefore,this study compares and analyzes the effects of electrical stimulation process and the coupling of electrical stimulation and electrodialysis on microbial metabolic hydrogen production.By comparing with other carbon sources,the feasibility of separating fermentation broth as a carbon source is analyzed.The effect of N on biological denitrification system was investigated.The effect of separating fermentation broth on strengthening campus sewage treatment was investigated.The purpose of this study is to improve the hydrogen production efficiency of the dark fermentation process,and to provide new high-quality carbon sources and technical ideas for the biological nitrogen removal of low-carbon-to-nitrogen ratio wastewater.Direct currents of four different current densities of 0.3m A/cm~2,0.5m A/cm~2,1.0m A/cm~2,and 2.0m A/cm~2were fed into the hydrogen-producing fermentation reactor,and the effect of current density on the hydrogen production of E.harbinese B49 bacteria was investigated.Among them,0.3m A/cm~2current density has the best electric stimulation effect,and the obtained biomass,glucose utilization rate and hydrogen production are0.55g/L,76%,1247.26mg/L and 1100m L,respectively.The separation of acetic acid from the fermentation broth by bipolar membrane electrodialysis technology can significantly improve the metabolic hydrogen production of E.harbinese B49,and the obtained biomass,glucose utilization and hydrogen production are 0.56g/L,81.15%and 1278m L,respectively.The combined use of the electrical stimulation process and the bipolar membrane electrodialysis process to promote the hydrogen production of E.harbinese B49 is better than that of a single process.The microbial accumulation,glucose utilization,and hydrogen production are 0.77g/L and 89%,respectively And 1458m L,1.38 times,1.16 times,and 1.20times of the electrical stimulation process,respectively.In addition,the p H of the system should be increased after electrodialysis to provide more suitable environmental conditions for the metabolic hydrogen production of E.harbinese B49.In order to realize the resource utilization of fermentation products,the denitrification and denitrification effects of four kinds of carbon sources such as glucose,sodium acetate,ethanol,and corncob soaking solution were compared as the carbon source.The removal rate of nitrate nitrogen was sodium acetate>glucose>isolated fermentation broth>corn cob soaking liquor>ethanol.The maximum accumulated amounts of nitrite nitrogen were7.33mg/L,11.28 mg/L,9.24 mg/L,3.85 mg/L,and 4.13 mg/L.The separated fermentation broth can be used as an additional carbon source for the denitrification reaction.Under the conditions of initial p H values of 6.00,7.00,8.00,9.00,and 10.00,the denitrification and denitrification effects of the separated fermentation broth were investigated.When the initial p H was 7.00,the denitrification effect of the separation fermentation broth was the best.The nitrate nitrogen was basically removed when the reaction reached 4h,and the COD degradation rate was 98%at the end of the reaction.By controlling the initial C/N to be 2,4,6,and 8,respectively,the influence of the initial C/N on the denitrification and denitrification performance of the separation fermentation broth was investigated.A good denitrification effect was obtained when the initial C/N was 6 and 8.At the end of the reaction,nitrate nitrogen was almost completely removed,and the nitrite nitrogen content was less than 1.67 mg/L.The separation fermentation broth was used as an external carbon source,and the SBR reactor was used to treat campus domestic sewage.The average COD degradation rate and TN removal rate of campus domestic sewage with C/N of 4.5 were only 56.06%and57.65%.When the feed water C/N was increased to 6 by adding a separate fermentation broth,the average COD degradation rate and TN removal rate after the system was stabilized were 73.97%and 82.97%,and the effluent COD and TN were 61.46mg/L and7.11mg/L.When the separation fermentation broth was continuously added to the inlet water C/N of 7.5,the average COD degradation rate and TN removal rate increased by 2.54%and1.31%after the system was stable,and the effluent COD and TN were 73.64mg/L and6.24mg/L.Excessive addition of carbon source will increase the COD concentration in the effluent,and the removal of TN will be small.It is recommended to control the amount of fermentation broth to reasonably control the C/N of the incoming water to about 6. |
