Investigation of chemical pretreatment of rice straw with ammonia, urea and sodium hydroxide

Document Type : Research Paper

Authors

1 Former Graduate Student, Sary University of Agriculture and Natural Resources, Iran

2 Assistant Professor, Sary University of Agriculture and Natural Resources, Iran

Abstract

Agricultural residues have high potential to produce biogas, but they contain lignocellulosic
materials which are not easily degradable, so the pretreatment is required. Chemical pretreatment
increases the rate of degradation and efficiency of biogas production. This study has been
investigated the effect of 4% -urea, 5%-ammonia and 8%-sodium hydroxide on degradation of rice
straw and production of biogas combined with sheep manure with three Carbon to Nitrogen ratios
(15, 20 and 29) in anaerobic digester at temperature of 40±2 °C. The process was performed in a
factorial design with two factors in three replications. Results showed that the cumulative
production of biogas and the maximum percent of Methane are 594 (ml/VSadd ) (that is 133.33%
more than the control) and 71% that they achieved by 8%-NaOH-pretreated straw combined with
manure in Carbon to Nitrogen ratio of 29. The results show the positive effect of chemical
pretreatment of rice straw on efficiency of biogas production combined with sheep manure.

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