Study On The Biogas Production From Kitchen Waste By Anaerobic Digestion

With the improvement of the level of living in our country, the producton of food waste fiercely increased, which trigger a series of pollution problems. Food waste have the characteristic of high-organic and easily biodegradiable, which make it a valuable renewable resource. Due to be short of reasonable treatment technologies, a range of events seriously hurting human health happened, such as "shaoshui oil" and "shaoshui pig". Anaerobic digestion of food waste can not only solve the disposal problem, but also recycle energy and alleviate the energy crisis.In this paper, the following aspects were researched and the corresponding results were obtained:(1)Kitchen waste mainly consist of rice (44.5%) and vegetables (33.2%), with the characteristic of high moisture content (80%), high organic matter (VS/TS 90%), and rapidly acidification. The physicoche-mical properties analysis showed that the kitchen waste meet the requirements of anaerobic digestion. The accumulative biogas yield of rice, vegetable, meat and kitchen waste mixture were 478.2,433.3,206.8 and 508.3 mL/gVS, respectively.(2) An optimum anaerobic digestion condition, temperature 55℃, pH value 7, inoculums ratio 30%, moisture content 8%, was obtained. In this condition, the yield of anaerobic biogas was 633.8 mL/gVS. The order of influence factors on biogas production rate were:temperature, pH, inoculums rates and total solid content.(3)In order to study the biogas production from kitchen waste by anaerobic digestion, the way of promoting the anaerobic digestion (the domestication of inoculum way, grease removal, alkali treatment, heat treatment, additives, and reuse of biogas slurry residue, etc)were reseached in this chapter. The main results are as follows:the best domesticated way is rest airtightly for a week; the best grease removal degree is washed with the same quality water; the appropriate time of 100℃thermal treatment is 15mins; the best additive combination is alkali (Ca (OH)2) 40g/kgTS food waste, activated carbon 40g/kgTS food waste and nutrient 30 mL/kgTS food waste; the best reuse way of residue and slurry is acting as the inoculum and regulating water, separately.With the aim of providing the theoretical argument and basic data for food waste treatment, the physical and chemical properties of food waste, the mechanism of anaerobic fermentation, the optimum condition of anaerobic digestion and the way of promoting the anaerobic digestion were investigated in this paper.