Research On Engineering Bacteria Of Food Waste Sequencing Batch Aerobic Composting

Food waste is a kind of biomass resource with high recyclable value.Traditional treatment methods such as landfills and incineration cannot realize food waste recycling.Aerobic composting technology is mature,easy to operate,safe,and stable,and has become a hot spot for food waste treatment under the background of domestic waste classification.Studies have shown that engineered bacteria can improve the efficiency of aerobic composting and enhance the stability of the system.In this paper,by analyzing the composition of microbial species in the process of food waste composting,screening the main functional bacteria,obtaining the corresponding engineering bacteria through purification and enrichment culture,studying the freeze-drying process conditions,and obtaining the engineering bacteria powder for kitchen waste composting,and experimental verification The main work and outcomes are as follows:Screening of functional bacteria for aerobic composting of kitchen waste was carried out.A total of 6 food waste composting experimental devices: the moisture content of the auxiliary materials is 15%,the reactor temperature is 40°C,45°C,and 50°C,respectively;the reactor temperature is 50°C,and the moisture content of the auxiliary materials is 15%,20%,and 25%,respectively.Add 1.5 kg of green waste auxiliary materials to each reactor at one time and add500 g of kitchen waste every day.During the composting process,measure the weight,organic matter,total nitrogen and carbon-nitrogen ratio of the mixed materials,and measure the composting efficiency by the weight loss rate.main indicators.The results show that the weight loss effect of food waste is greatly affected by temperature,the higher the temperature,the better the weight loss effect,and it is not affected by the moisture content of auxiliary materials.In the reactor with the best weight loss effect,Leuconostoc,Lactococcus and Pleurotus were screened out,and their relative abundances were 18.3%,16.6% and 22.3%,respectively.The isolation,purification,identification and enrichment culture of functional bacteria for aerobic composting of kitchen waste were carried out.The compost samples were selected from the reactor with the best weight loss effect,and 4 bacterial strains were isolated by using MRS(lactic acid bacteria medium)as the separation matrix;Two strains of Leuconostoc and Lactobacillus were identified;through 16 S r DNA high-throughput sequencing,compared with the 16 S sliva138 bacterial database,it was determined that the two screened strains were Leuconostoc and Lactobacillus.Taking the number of viable bacteria as the main indicator,the optimal conditions for a high-density culture of a 1:1 mixed bacterial solution of Leuconostoc and Lactobacillus were the temperature of 37°C and the inoculum volume of 3%.The preparation and application of bacterial powder for aerobic composting engineering of kitchen waste were carried out.According to the water content and the number of viable bacteria as the basis for discrimination,the freeze-drying process conditions of the kitchen waste aerobic composting engineering bacteria with a total process of 24 hours of pre-freezing and drying,the thickness of the bacteria liquid of 40 mm and the vacuum degree of 5～10 m Torr were determined;the engineering bacteria powder The best storage temperature is 4°C.The comparative experiment between the reactor with engineering bacteria powder and the one without engineering bacteria powder shows that the composting efficiency is significantly improved after adding engineering bacteria powder,the weight loss rate of food waste material reaches 77.6% within 0～5 d,and the final material loses weight.The moisture content of the food waste material dropped to 14.0% within 0～12 d,and the final moisture content of the material was 4.8%,which was 5.0% lower than that of the control group.and 1.5%;the organic matter content of the kitchen waste material dropped to 79.2% within 0～6 days,and the organic matter content of the final material was 69.8%,which was 2.1% and 1.6% lower than the control group;the carbon-nitrogen ratio of the material decreased within 0～6 days When it reached26.8,the carbon-nitrogen ratio of the final material was 10.6,which was reduced by 4.4 and 5.9compared with the control group;the time to enter the stable composting state was shortened from 10 d to 5 d.The research results provide technical support for the popularization and application of kitchen waste fertilizer.