The Study Of Hydrogen Production Characteristics Of Bacterial Mixed Culture Biofilm Fermentation

Due to the non-renewability of fossil fuels and environmental pollution,research on fossil energy substitutes is increasing,because hydrogen can receive people's attention with its high calorific value and only by-product water.But at present,hydrogen is mainly produced by the conversion of fossil energy,which consumes a lot of energy and causes serious secondary pollution.Bio-hydrogen technology is a low-cost,low-pollution technology that makes the hydrogen preparation process simple and feasible,and can produce clean energy while processing the machine wastewater.In order to solve the problems of low biomass and poor fermentation stability of existing biological hydrogen production technology,in this paper,two strains of hydrogen-producing bacteria,Bacillus Cereus A1 and Brevumdimonas naejangsanensis B1,were screened and isolated from the activated sludge.Using cotton fiber as the carrier,the biofilm immobilization technology was used to realize the rapid culture of the biofilm,and the biofilm was used for anaerobic fermentation to produce hydrogen.The hydrogen production process of pure cultured cells is easy to be contaminated by foreign bacteria,and the substrate range is relatively narrow,so there are some problems in practical application.The use of A1 and B1 mixed bacteria BF biofilm can expand the living environment of bacteria,increase the tolerance of the two bacteria and produce more hydrogen,so the factors affecting the formation of biofilm were studied.The results showed that adding 1%glucose into the seed solution could shorten the growth rate of biofilm,increase the cumulative hydrogen production during fermentation,and increase the substrate utilization rate to 91.8%.Modification of the carrier with 0.2g/L chitosan solution can increase the binding capacity between the carrier and bacteria,thus improving the biomass.The results showed that A1 and B1 biofilms could expand the living environment of bacteria,increase the tolerance of the two bacteria and generate more hydrogen.Using adsorption,embedding,flocculation of three methods for immobilized improve A1,B1 production performance,the optimal results show that the biological membrane immobilized performance,producing hydrogen yield of three groups of experiments were 6.36 H2/g starch(straw),5.50 H2/g starch(gel),7.19 H2/g starch(biofilm),compared with the free group,biological membrane immobilized producing hydrogen capacity increased by 22%.At the same time,in order to investigate the influence of different BF culture methods on the hydrogen production performance of fermentation,the experiment compared the hydrogen production effect of static and dynamic method of BF biofilm culture.The experimental results showed that compared with the static culture,the biofilm cultured by the dynamic method can significantly improve the biomass,and the biofilm dehydrogenase activity is more stable.In the process of fermentation,the biofilm in dynamic culture shows better hydrogen production performance,and its hydrogen production yield is 1.69 H2·(mol·glucose)-1,which is 11.9%and 39.7%higher than the biofilm in static culture and free fermentation,respectively.Hydrogen production by dynamic culture of biofilm fermentation provides a research basis for hydrogen production by biofilm reactor and provides a new idea for wastewater treatment in practical application.