This study was conducted in Go Cong Tay district (Tien Giang province, Vietnam) to estimate the potential of using residue from rice production, particularly, rice straw, to produce biochar at household scale. The annual rice yield of Go Cong Tay district is 185,072 tons/year. It creates about 233,190 tons of rice straw per year. Currently, most of these residues are open burned by the farmers. This study examined the experimental biochar production in different modes of combustion (6 h, 10 h and 15 h). The results show that 6 h of combustion is the best condition due to high yield of biochar, less ash and low amounts of incompleted biochar. With 100 kg of rice straw sticks, 48.25 ± 2.25 kg of biochar was produced. The amount of ash and incompleted biochar was low, 0.75 ± 0.13 kg and 3.95 ± 1.33 kg, respectively. The thermal energy of biochar from rice straw is about 4,030 kcal/kg, which is higher than other similar materials such as chaff, sawdust, etc. The suggested model of biochar production is compatible with household scale due to the short time of combustion, high productivity and the method is easy to perform. This practice reduces agricultural waste, protects soil and creates useful thermal energy for household activities (e.g., cooking). The ash created from biochar production can be used for fertilizing. © 2018, Faculty of Environment and Resource Studies,Mahidol University. All rights reserved.
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