Enhanced Analysis Of Aerobic Fermentation Of Kitchen Waste And Sludge By Microbial Agents

In recent years,the concept of smart city,eco-city and low-carbon city construction and development is being gradually promoted,so the community-based intelligent,integrated and rapid treatment devices are gradually gaining attention.The massive generation of solid waste such as kitchen waste and sludge has become one of the important factors limiting the rapid development of cities.In this study,kitchen waste and sludge were used as the research objects,and microbial agents were dosed.Firstly,the promotion effect of microbial agents on the degradation of kitchen waste was analyzed and their optimal dosing amount was determined.Secondly,the effect of humus and microbial agents on the aerobic fermentation of sludge combined with kitchen waste was determined by comparing the physical and chemical properties of substrate,nutrient elements,decay degree index,enzyme activity and mechanism and combining with the change of microbial community structure,in order to provide theoretical support for the rapid aerobic fermentation of microbial agents and the screening of superior strains in the future,and to provide insight for the strategy of improving the efficiency of solid waste co-composting in the future.The main conclusions were as follows.The main conclusions were obtained as follows.(1)The aerobic fermentation and composting of kitchen waste was carried out by adopting the microbial agent dosing ratios of 0,1 %,5 % and 15 % and using wood chips as conditioning agent.The analysis of physicochemical indexes such as temperature,water content,p H,conductivity and redox potential showed that the use of 15 % microbial agent dosing had an excellent effect on the rapid increase of temperature and the rapid aerobic degradation of substrate.(2)The evaluation of decay indexes such as perceptual odor and humic acid optical properties(E4/E6)showed that the addition of 15% microbial agent had a better effect on the substrate decay.The relative seed germination indices of the extracts of the four reactors showed a gradual increase as the reaction progressed until the end of the reaction,and the seed germination indices of the four reactions were 52.24 %,66.98 %,93.86 % and 121.10 %,respectively.The reduction index showed that the weight reduction and degradation effect could reach 60.36% with the addition of 15 %microbicides.Through economic costing,the composting cost of 1 kg of substrate is about 1.163 RMB,compared with the traditional aerobic composting treatment,the dosage of 15 % of microbial agent is used to realize the solid waste resource recovery and economic advantage at the same time.(4)In the second stage,three experiments were conducted: sludge alone combined with kitchen waste(CK),pile A with 15 % of microbial agent,and pile B with the decomposed soil obtained from the first stage of the experiment(15 % of bacterial agent).The results showed that the addition of microbial agents could raise the temperature and keep the high temperature for a long period,which had a positive promotion effect on improving the substrate degradation and the promotion effect was greater than that of humus addition.(5)By monitoring the apparent effect of fermentation substrate,carbon to nitrogen ratio,E4/E6 and other decay evaluation data,all of them showed that microbial agent addition promoted the decay of substrate with the best effect and humus with the second best effect.At the end of the reaction,the seed germination indices of the three reactions were 227.89 %,258.54 % and 211.57 %,respectively,all of which were >85 %,indicating that the fermentation products had decayed.(6)Analysis of the changes in the enzymatic activities of the four enzymes(catalase,urease,cellulase and protease)in the three piles showed that the microbial agent dosing significantly increased the activities of the four enzymes,and all were closely related to the temperature changes.The microbial data showed that the addition of microbial agents improved the homogeneity of microorganisms at the phylum level for both bacteria and fungi,and that the metabolic pathways of the fermentation systems of the three reactors were dominated by carbohydrate transport metabolism and amino acid transport metabolism.(7)The data on the addition of decomposing soil showed that the substrate had an effect on the inheritance of microorganisms in the previous stage and promoted the decomposition of the pile,and the effect was second only to the microbial agent addition.The analysis of the dominant strains showed that the future screening of the dominant genera of microorganisms for the aerobic fermentation process should focus on the Firmicutes and Bacillus,while the fungi should focus on the genus of Issatchenkia.