Development Of Static Magnetic Field Enhanced Anaerobic Fermentation System And Performance Optimization

Anaerobic fermentation is a sustainable and highly efficient technology that uses organic waste as a substrate and produces biomass energy under the synergy of a series of anaerobic microorganisms.It can not only solve the environmental problems caused by organic waste dumping,but also convert it into a series of biomass clean energy such as methane.Anaerobic microorganisms have a slow reproduction rate and are easily affected by environmental conditions such as temperature and pH,resulting in unstable gas production.Static magnetic field(SMF)is a constant magnetic field generated by permanent magnets,which has a certain promotion effect on the reproduction of some bacterial groups.In this paper,SMF enhanced anaerobic fermentation system is taken as the research object to optimize the reaction conditions such as temperature and magnetic field strength.Taking the gas production in the SMF environment as an indicator,combined with gene sequencing technology,the most important Research on key technologies such as gas production efficiency under good SMF intensity;based on the grey theory,the best gas production prediction model was established to realize the efficient,continuous and stable operation of the SMF enhanced anaerobic fermentation system.First,based on the four-stage theory of anaerobic fermentation,the theoretical research on anaerobic fermentation to produce methane was carried out from the perspective of metabolism.By summarizing some key parameters that affect the growth environment of microorganisms during fermentation,such as temperature,pH,chemical oxygen demand(COD),volatile fatty acids(VFAs),redox potential(ORP),etc.Based on this,SMF enhanced anaerobic fermentation theoretical research was carried out,and the mechanism of the influence of the magnetic field on the anaerobic fermentation process was expounded from two aspects of the change of the microorganism itself.Based on the above research,the mechanism by which the magnetic field affects the anaerobic fermentation process is described.Secondly,the experimental conditions of anaerobic fermentation were optimized,and the optimal operating temperature of the system was determined to be 55 ± 1?,the optimal pH range was 6.5-7.5,and the ORP value range during fermentation was-570 to-520,which was normal range;The results of the SMF intensity optimization experiment showed that the number of colonies(129.09 CFU ml-1)and the enrichment efficiency of bacterial solution(85.5%)were the highest at 11.4 mT intensity.Then the key technology research of SMF enhanced anaerobic fermentation was carried out.The experiment ran for 35 days.Compared with the non-magnetic field(NMF)treatment,the final total gas production of the SMF group increased by 19.5%,of which the CH4 content increased by 20%.It is more stable,the rising stage of gas production is shortened by 1 day,and the COD degradation rate is significantly increased(45.7%);High-throughput sequencing of 16S rRNA showed that SMF enhancement not only affected the bacterial community composition to a certain extent,but also significantly increased the percentage of methanogens;At the same time,it was found that methanogens were the main methanogenic archaea during the decay stage.The above results show that SMF has great potential in biogas production,which can improve the system gas production rate and organic load absorption capacity.And the prediction of the relationship between the amount of feed and the amount of gas produced in the biogas supply can form a reasonable supply and demand balance between the gas supply station and the user;Through the calculation and analysis of the experimental data of the multiple linear regression model and the gray correlation model,the prediction deviation of the gray correlation model(5.51%)is smaller than the multiple linear regression model(32.9%)in the prediction of total gas production,so the gray correlation model is selected as the experimental prediction model.Finally,completed the development of the SMF enhanced anaerobic fermentation system,and on this basis,the gas production performance test of the SMF enhanced anaerobic fermentation system was carried out.The test results showed that the total gas production of the SMF group increased by 44.2%compared with the control group.The goal of continuous,stable and efficient gas production.At the same time,through the prediction of gas production,the corresponding relationship between gas production capacity and feed volume is initially achieved,which lays the foundation for achieving the balance of gas production supply and demand.