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Environmental Impacts of Alternative Uses of Rice Husk for Thailand
Jittima Prasara-A,* School of Global Studies, Social Science and Planning, RMIT University
Tim Grant, Centre for Design, RMIT UniversityThailand is one of the largest rice producing countries in the world. In recent year, the nation produces about 29 million tonnes annually (1). Rice husks, which are a by-product of rice production, account for 23% of total paddy weight. Being bulky, the husks cause significant disposal problems for the rice mill owners. Furthermore, the methane gas that is released when the husk is fermented by micro-organisms is thought to contribute to global warming. Also, rice husk is one of the potential biomass sources in Thailand. The Thai government has encouraged the use of biomass fuel to help reduce global climate change and reserve fossil fuel resources. Therefore, rice husks have been utilized in several ways.
One of the ordinary uses of rice husks has been as a source of energy within the rice mills. However, there were still surplus rice husks from the process after being used in paddy drying and milling (2). More recently, rice husks have been put to use within the industrial sectors such as electricity generation, cement manufacture, agriculture etc. Although there are many alternative ways of rice husk utilization, the environmental impacts of these have not yet been widely investigated within the Thai context.
This presentation compares the environmental impacts of different rice husk use pathways, i.e. use in power generation, cement manufacture and cellulosic ethanol production. A consequential LCA method has been used in the comparison of options to determine how these beneficial uses of rice husks will lead to substitution of virgin materials such as coal, cement raw materials and petroleum product, and changes in the emission profiles of these production systems. The impact indicators analyzed are abiotic depletion, global warming, human toxicity, ecotoxicity, photochemical oxidation, acidification, eutrophication and water use. However, this research is on-going and results will be presented in the slide presentation.
(1) Office of Agricultural Economics. Rice: Harvested area, production and yield of major countries, 2004-2006. 2006 [cited 2007 7 December]; Available from: http://www.oae.go.th/statistic/yearbook49/section1/sec1table1.pdf.
(2) The EC-ASEAN COGEN Programme, Evaluation of Conditions for Electricity Production Based on Biomass: Final report for RAMBOLL. 1998, The EC-ASEAN COGEN Programme: Bangkok.
* corresponding author: jittima.prasara-a@rmit.edu.au