Investigation And Anaerobic Digestion Feasibility Of Food Waste In Hangzhou

In recent years, with the improvement of Chinese urban living standards, the production of food waste increased rapidly. Recently, annual food waste production in China has reached 50 million tons, most of large municipal cities of China, food waste production are above 1,000 t/d. Due to lack of appropriate treatment and disposal technologies, serious food waste pollution problems have been increasing. On the other hand, rich in organic nutrients, food waste is an ideal source for anaerobic biogas produciton.In this paper, a survey of food waste in Hangzhou was performed. Physical and chemical properties of the typical food waste from school cafeteria were analysised. On the basis of the chemical composition, some anaerobic digestion experiments of food waste were carried out for the investigation of the feasibility of biogas production from food waste. Meanwhile some bacteria involued in the biogas production process were also detected. Detailed results are as follows:First, a questionnaire survey of five main Districts of Hangzhou city(Shangcheng, Xiacheng, Gongshui, West Lake and the West Lake Scenic Area) were implemented. Results showed that annual food waste production in Hangzhou city is around 27,140 ton. 82.60% of food waste in Hangzhou was used for feeding livestock. Although, 52.95% of food waste in the city was classified, only 17.19%' was transported by the special vehicles. Our results indicated that there exists severe sanitary problems and potencial risk in food waste safety, due to the improper treatment of the municipal waste food.Secondly, physical and chemical properties of food waste of Zhejiang University (Huajiachi, Xixi, Yuquan, Zijingang) were analyzed. Results showed that the impurity content in food waste is about 10% 20%. However, the food waste is rich in organic matter, the major organic component of food waste coarse protein, total starch, and coarse fat. VS contents in food waste ranged from 20% to 30%, C / N was about 9²1, which is conducive to the growth of anaerobic microorganisms.On the basis of the chemical composition analyss, a preliminary study of high temperature anaerobic methane fermentation was conducted. Results showed that the optimal condition for food waste anaerobic biogas production were substrate concentration 15gVS/L, innoculum size 30% (v/v), and the fermentation temperature 55°C. The highest methane conversion rate obtained in this study was 0.4571L CH₄/gVS. In addition, microborganisms involved in the fermentation process were determined by both culturarable and non-culturarable approaches. Results suggested that there was no appareatly relationship between methane production rate and the total number of methanegnesis.This paper had analysised the potential market for the technology of food waste methane fermentation in Hangzhou, through the survey of food waste. And severe experiments had taken for confirmed the technical feasibility food waste methane fermentation, explore the anaerobic methane fermentation process control and conditions of microbiology. These results provide a basis for applied research projects of the feasibility of anaerobic digestion technology for food waste anaerobic methane fermentation.