Study On Volatile Fatty Acid Production By Continuous Anaerobic Fermentation With Peanut Residue As Substrate

Anaerobic fermentation of acid is one of the hotspots of organic solid waste recycling.Volatile Fatty Acids(VFAs)can be used as an additional carbon source for biological nitrogen andphosphorus removal,and can also be used as a synthetic raw material for chemical materials.Industrial production of high value-added products.However,there are few studies on the production of even carbon VFAs by anaerobic fermentation using a continuous flow process after pretreatment of organic solid waste.In this paper,we explored the control strategy of continuous anaerobic fermentation acid production system,revealing the effects of HRT,temperature and influent load on the yield anddistribution of VFAs,and investigating the inhibition of high ammonia nitrogen on the accumulation of even VFAs,and at the same time,in order to better understand and explain Fermentation acid production process,the application of microbial community analysis method,for the reuse of peanut residue organic solid waste,and the development of continuous anaerobic fermentation acid production process.In the continuous flow mode,after the completion of the CSTR reactor by alkaline fermentation,the effects of HRT,temperature and influent load on the anaerobic fermentation of peanut slagVFAs were studied.The soluble protein andglycogen in the fermentation process were investigated.Changes in nitrogen andphosphorus dissolution,VFAs yield,and monoacid components.The results showed that alkaline fermentation can inhibit the activity of methanogens,improve the hydrolysis efficiency of peanut residue substrate,and enhance the tolerance of acid-producing bacteria to ammonia nitrogen toxicity,which is beneficial to the accumulation of VFAs.The main organic matter in peanut residue is protein and sugar.Originally,the change of working conditions has obvious influence on the degradation of protein,and the effect on glycogen is small,and the degradation rate is higher than 90%;in HRT=6d,T=35°C and influent load(in COD)Under the condition,peanut slag produced the best VFAs,and its TVFAs concentration was 17422~17567mg/L,of which acetic acid accounted for 82.74~83.37%,and even acid accounted for 91.66~92.4%;the change of working conditions could not affect its fermentation.The acid production type was dominated by even acid fermentation;the inhibition threshold of high concentration ammonia nitrogen on VFAs accumulation was 2129.02mg/L.Combined with static batch test,the optimum C/N of peanut slag and fruit peel mixed fermentation was studied.In the continuous flow mode,the inhibitory effect of mixed fermentation high ammonia nitrogen on the accumulation of even carbon VFAs was investigated.The results showed that the mixed fermentation could alleviate the inhibitory effect of high concentration ammonia nitrogen on even carbon VFAs.Under the condition of C/N56/1,the ammonia nitrogen content was the lowest and the acid production effect was the best.The even carbon VFAs production could be maintained at 14000~14089mg/L.Through the analysis of the microbialdiversity at the three levels of the door,the class and the genus,the changes in the control conditions of each working condition will affect the diversity of microorganisms and the succession of intergeneric species;the alkaline fermentation is reduced.The abundance of methanogens increases the diversity of hydrolyzed bacteria in the system.The content of Firmicutes related to hydrolysis is increased,and the abundance is as high as 90%,which is more conducive to the occurrence of hydrolysis and acid production.Acid-relatedgenus Anaerosalibacter,Caldicoprobacter,andIgnatzschineria are all increased.