The Potential of Biogas Production and an Environmental Status in Pig and Dairy Farms of Thailand

Abstract

This study was aimed at analysis of potential biogas production in pig and dairy farms throughout the country to quantify an amount of generated biogas possible to replace liquid petroleum gas (LPG) and kWh electrical energy. Assumptions for the analysis involved minimum farm size, minimum years of farm operation, information on age and size of standing animals, wish of farm to use a biogas plant and enforcement of waste water standard. Information on environmental status of those farms was included in the study. The study was carried out under the Biogas Map Project in pig and dairy farms of Thailand. All of the data were obtained from farm survey with questionaires and interviewed by officials of the Department of Livestock Development, the Department of Agricultural Extension and personels of private livestock-business sector during February 1999 ~ February 2000. A livestock farm data – base was created accordingly for processing to be used by the biogas promotion agency, livestock sectors, farmers and people interested in biogas production and to provide information on pig and dairy cattle statistics. Data obtained from 19,239 farms which composed of 5,978 pig and 13,261 dairy farms and distributed mostly in the western region. All of the pig farms were categorized as 2,073 fattening (34.68 %), 1,975 fattening with breeding (33.03 %) and 1,930 breeding (32.29 %) operations only. Thirty eight point six percent of all farms were located less than 1 km away from community. Thirty-three point four percent of them were between 1~3 km away. Sixty three point one percent of the dairy farms and 49.15% of the pig farms situated near public waters. Most of the farms flushed and cleaned animal pens with water after or before removal of manure. Piling of solid manure were practiced in 75.66% and 72.63% of the pig and the dairy farms before selling away. Cleaning the animal pen was a major means of odor control in 86.23% and 92.35% of the pig and the dairy farms respectively. Besides, 42.96% and 78.61% of the pig and the dairy farms limited the amount of released waste water by applying the least amount of flushing water. Most of the pig and the dairy farms (67.94% and 58.24%) accepted that odor, flies and waste water were pollution problems in the farm but 55% and 59% of them, respectively, claimed that they had no problem with neighborhood. However 29.98% of the pig farms were given warning from local administration and 5.15% of them were complaint by neighbors.

            The pig and the dairy farms of 3.21% and 2.08%, respectively, had biogas plants. As 79.69% of the pig farms built their own biogas plants, only 17.82% of the dairy farms did the same way. They (51.82% and 49.96%) were still very satisfied with their existing biogas plants. Another 1,984 and 4,590 pig and dairy farms wanted to have a biogas plant in spite of different readiness of investment. Higher percentage of the pig farms considered environmental reasoning for having a biogas plant than that of the dairy farms.

            One thousand two hundred and fourty seven farms including small, medium and large size were classified as the potential farms in biogas production with a total 127,946  livestock unit (LSU). They would require a total of 255,892 cbm of biogas digesters.

            Two thousand one hundred and twenty dairy farms could be classified as the potential biogas producing farms with 22,720 LSU. They would reqire altogether 45,440 cbm of biogas digesters. All feasible dairy farms throughout the country had 70% of the total number of LSU possible for biogas production. They were estimated to hold 125,239 feasible LSU and would require 250,478 cbm biogas digesters to produce 15.9 million cbm biogas yearly. This amount of biogas was comparable to 20.6 million baht LPG per year.

            All of the farms, except those below the minimum size which were not sustainable to have even a biogas plant, hold a total animal population as 654,698 LSU. They would require 1.3 million cbm of biogas digesters and produce annually 151.3 million cbm biogas, comparable to 904.6 million baht LPG.

            The Department of Agricultural Extension and the Biogas Advisory Unit, Chiang Mai University with their expanded target until the year 2002/3 would be 3.5 times underdisseminate construction of biogas digesters than the anticipated digester volume. If the total required volume of the biogas digester in all feasible farms were considered, those expanded target would be 15 time lower. A clear gap in biogas dissemination was found for the 1,600 middle pig farms and large dairy farms that would require a biogas digester size bigger than 100 to that smaller than 1,000 cbm.