Study On Anaerobic Digestion Of Kitchen Waste And Pilot Scale-Up

China is a large country with 1,400 million people and the consumption of food is huge,therefore lots of food wastes are produced.Employing anaerobic fermentation process to deal with kitchen waste is paid more and more attention.Compared to foreign countries,China's industrial application is still a serious shortage.In this study,through the experiment of anaerobic fermentation of kitchen waste and the scale-up design,more results and experiences can be obtained to improve the process and technology of kitchen waste anaerobic fermentation.Firstly,fresh kitchen waste was handled by the two kinds of physical pretreatments of screening and crushing.Through measuring the basic properties of VS,TS and gas production potential,the maximum biogas production rate could be estimated.The experiments were carried out in two continuous stirred tank reactors,single phase and two phases,respectively.The different organic loading rates were 1.5,2 and 3 g VS/(L·d).With 1.5 g VS/(L·d)feed,the methane yield was 420.2 mL/(g VS·d)in the single-phase reactor,while the acid phase in the two-phase system did not produce gas and the methane production was 396.2 mL/(g VS·d)in the methanogenic phase.When the feed rate was 2 g VS/(L·d),the maximum biogas production rates were 798.0 and 618.8 mL/(g VS·d),respectively;the maximum methane production rates of single phase and two phase were 520.8 and 464.1 mL/(g VS·d),respectively.Under wet anaerobic fermentation conditions,single-phase system is more suitable for long-term anaerobic digestion of kitchen waste.Secondly,the compost of solid portion of kitchen waste and the treatment of wastewater were studied.The composting effect showed better performance under the condition of 70?,and the additives,such as inoculants,straw,etc.,could accelerate and promote kitchen waste composting.A large amount of biogas slurry will be produced after the fermentation of kitchen waste.In order to make wastewater reach the emission standards,a microalgae reactor and a membrane bioreactor were designed to form the two-stage wastewater treatment system.Finally,from the perspective of industrialization,the main process for kitchen waste disposal was designed,According to the standard of energy and chemical industry,small test results and the actual situation,a pilot level of technology package was designed to provide the basis for further engineering design.The process mainly included the pretreatment of kitchen waste,anaerobic fermentation and gas purification.The evaluation of process and economic benefit were also carried out.From the evaluation indicators,the project of anaerobic fermentation for kitchen waste is feasible.