2020 年 11 巻 2 号 p. 92-97
Biogas systems are being applied at commercial pig farms and at starch processing plants to manage their wastes and produce biogas for generating electricity or heat for on-site use. The installation numbers are increasing in Cambodia. The data on potential biogas production quantity from different feedstocks as well as on biogas quality are required to design the biogas systems. The purposes of this study was to determine biogas production and biogas quality from dairy cow manure produced in pilot digesters, and to analyze the variation in biogas production and quality during the year of 2019 and 2020. Pilot bio- digesters were installed at the Biogas Technology and Information Center, a research unit located in the Royal University of Agriculture, to obtain these data, since it is easier to do the experiments with the pilot digesters than that with commercial ones. The experiments were conducted during the year of 2019. In the experiments, 3 identical floating drum bio-digesters were used. Each bio-digester has 1 m3 of volume and has been supplied mixture of 5-10 kg of fresh manure from dairy cattle with 5-10 liters of water every day. The daily biogas production quantity was recorded using a gas flow meter attached to the outlet of each bio- digester; also the gas quality, such as methane, carbon dioxide, oxygen, and hydrogen sulfide was measured using a portable biogas analyzer. The average rate of biogas production was around 37 liters of biogas per kg of wet manure. Average percentage of methane was around 52%, and average concentration of hydrogen sulfide varied from around 390 ppm to 604 ppm. These two parameters are the main indicators of biogas quality.
