Influence And Control Of BPA In Aerobic Biological Treatment Of Food Waste

The vigorous development of the catering industry has continuously raised the amount of food waste,and its improper disposal has left many potential dangers to the ecological environment and human health.Aerobic biological treatment is an effective resource treatment technology for food waste,which can transform food waste into safe and stable resource-based products.As a common endocrine disruptor,bisphenol A(BPA)entering the environment will cause harm to human health and pose a greater environmental risk.As a plasticizer,BPA can directly enter the food waste and aerobic biological treatment system subsequently through the slow release of food plastic packaging,etc.,which may affect the microbial metabolism process of the aerobic biological treatment,thereby affecting its treatment efficiency.At present,more studies are necessary on the influence of BPA on the aerobic biological treatment of food waste for better control of its influences.Therefore,this study explored the influence of BPA on the aerobic biological treatment process of food waste,and screened out strains that efficiently degrading BPA and optimized the growth conditions of strains through single factor analysis and response surface experiment methods.The high-efficiency degradation strains were further added to the actual food waste aerobic biological treatment system to verify the degradation of BPA under bio-augmentation.The main experimental contents and research results are as follows:(1)From the perspectives of physical and chemical indicators and microbial community structure and metabolism,it can be concluded that BPA exposure will shorten 25% of the high temperature period of aerobic biological treatment and improve the C/N ratio of the product which further affected the maturity of the final product of aerobic biological treatment of food waste.And as the BPA content increased,the maturity decreased From the perspective of affecting the microbial community,BPA exposure decreased the abundance of Bacilli,and increased the abundance of Actinobacteria,Gammaproteobacteria,and Alphaproteobacteria.From the perspective of microbial metabolic activity,the presence of BPA led to a relative decrease in the metabolic activity of carbohydrates,amino acids and lipids in the later stage of aerobic biological treatment,which may lead to a decrease in the maturity of aerobic biological treatment.Therefore,BPA exposure will reduce the maturity of aerobic biological treatment of food waste by affecting the composition and metabolism of microorganisms.(2)In view of the adverse effects of BPA on the biological treatment of food waste,this study further explored the effects of different environmental factors on the degradation efficiency of BPA by screening high-efficiency degradation functional bacteria.Five strains that can effectively degrade BPA were screened from the sludge,and through optimization of conditions,two strains of high-efficiency BPA degradation bacteria were finally determined.The 16 S r DNA sequencing method was used to identify Klebsiella pneumoniae and Pseudomonas nitrite.Using single factor experiment and response surface experiment analysis,the optimal growth conditions for the two strains are as follows: Klebsiella pneumoniae can be grown at a culture temperature of 30℃,a culture p H of 7.4,and an external carbon source of 1% sucrose.To achieve the optimal degradation rate of 98.14%;Pseudomonas nitrite can reach the optimal degradation rate of 97.23% when the culture temperature is 30℃,the culture p H is 7.1,and the carbon source is 1% glucose.Further verification showed that the addition of carbon source is a key factor affecting the growth of functional bacteria and the degradation of BPA.The optimization of carbon source can increase the degradation efficiency of Klebsiella pneumoniae and Pseudomonas nitrite by 18.02%and 10.18%,respectively,and the degradation rate can reach 99.79% and 100%.(3)Add two strains of BPA high-efficiency degrading bacteria to the aerobic biological treatment system of food waste exposed to BPA in order to realize the enhancement of BPA degradation,and explore the effect of BPA degradation in the actual aerobic biological treatment of food waste.The results showed that the addition of high-efficiency degrading bacteria can alleviate the adverse effects of BPA on the food waste pile,prolong the high temperature period and further improve the maturity of the pile.In addition,the addition of BPA high-efficiency degrading bacteria increased the BPA degradation rate by 33.43%,which can realize the enhancement of BPA degradation in the actual pile.This study found the impact of BPA exposure in food waste on the aerobic biological treatment process,and proposed a biological control method for BPA through the screening of high-efficiency degrading bacteria and optimization of conditions,and then through the efficient degrading bacteria in the actual pile The additional application verifies the feasibility of bioaugmentation methods.This study provided research ideas and directions for the influence and control of BPA in the aerobic biological treatment of food waste,and was of great significance for assessing the potential environmental impact of emerging pollutants in food waste and proposing efficient control schemes.