Experiment and Research on Mesophlic Anaerobic Digester with Dairy Cattle Manure in Northern China

摘要

To treat animal wastes with the technology of anaerobic digestion can reduce environmental pollution and generate energy -- biogas, as well as produce a quick-acting, toxic-free fertilizer. The temperature in Northern China is comparatively low, to obtain a high biogas productivity, quick digestion of animal wastes in short period of time and high energy output in mesophilic fermentation poses a question. The answer is to create favorable conditions and environment for methanelization, i.e., rational process for biogas fermentation and advanced engineering system. The Gold Star Dairy Farm is located in the southern suburbs of Beijing. The 336 dairy cattle of the farm produce 10 tons of manure dairy, equivalent to 3600 tons of manure annually. A 300 cu m mesophilic digester system was established and started operation in the summer of 1984. In the two years of operation, the digester treats 6 ton manure and produces 180-200 cu m biogas everyday. Apart from heating and cooking for a canteen, the biogas produced can generate 150 kwh electricity everyday, which is utilized for milking and refrigeration of milk products. In addition, the biogas effluent can be used as fertilizer for farm land and feed for fish raising.