University of Sancti Spíritus 'José Martí Pérez', Cuba.
Water Sci Technol. 2012;65(6):1142-9. doi: 10.2166/wst.2012.951.
Agricultural solid residues are a potential renewable energy source. Rice harvesting and production in Sancti Spíritus province, Cuba, currently generates residues without an environmentally sustainable disposal route. Rice residues (rice straw, rice husk and rice residues from the drying process) are potentially an important carbon source for anaerobic digestion. For this paper, rice residues were placed for 36 days retention time in anaerobic batch reactor environments at both mesophilic (37 °C) and thermophilic (55 °C) conditions. Biogas and methane yield were determined as well as biogas composition. The results showed that rice straw as well as rice residues from the drying process had the highest biogas and methane yield. Temperature played an important role in determining both biogas yield and kinetics. In all cases, rice straw produced the highest yields; under mesophilic conditions the biogas yield was 0.43 m(3) kg(VS)(-1), under thermophilic conditions biogas yield reached 0.52 m(3) kg(VS)(-1). In the case of the rice husk, the biodegradability was very low. Methane content in all batches was kept above 55% vol. All digested material had a high carbon:nitrogen (C:N) ratio, even though significant biodegradation was recorded with the exception of rice husk. A first-order model can be used to describe the rice crop residues fermentation effectively.
农业固体残余物是一种潜在的可再生能源。在古巴圣斯皮里图斯省，水稻收割和生产目前产生的残余物没有环境可持续的处理途径。水稻残余物（稻草、稻壳和干燥过程中的稻渣）可能是厌氧消化的重要碳源。在本文中，将水稻残余物在中温（37°C）和高温（55°C）条件下的厌氧批量反应器环境中保持 36 天的停留时间。测定了沼气和甲烷的产率以及沼气成分。结果表明，稻草和干燥过程中的稻渣具有最高的沼气和甲烷产率。温度在确定沼气产率和动力学方面起着重要作用。在所有情况下，稻草都产生了最高的产量；在中温条件下，沼气产量为 0.43 m(3) kg(VS)(-1)，在高温条件下，沼气产量达到 0.52 m(3) kg(VS)(-1)。稻壳的生物降解性非常低。所有批次中的甲烷含量均保持在 55%vol 以上。所有消化后的物质的碳氮比（C:N）都很高，尽管除了稻壳外，还记录了显著的生物降解。可以使用一级模型有效地描述水稻作物残余物的发酵。
