ENERGY RECOVERY AND UTILIZABIRITY OF RESIDURE FOR RICE FIELD BY THERMOPHIRIC ANAEROBIC CO-DIGESTION OF SEWAGE SLUDGE AND RICE STRAW

Abstract

 A regional recycling system of energy and SiO₂ by thermophiric co-ditestion of sewage sludge and rice straw has been proposed. In this study, a continuous thermophilic co-digestion of sewage sludge (row sludge and excess sludge) and rice straw in a laboratory scale digestor was conducted. When 50% of rice straw was mixed to the sludge at the organic loadinlg 3.10 kg-VS/m³/day, stable biogas production was oboserved. Significant differences were observed in both bacterial and ar-chaeal community among monodigestion and co-digestion. The recovered enegty was estimated to increase by 40% by the addition of rice straw from the results of methane yield. The SiO₂ content of rice straw was higher than that of sewage sludge, and SiO₂ could be accumulated in the digested sludge, indicating that SiO₂ can be recycled by fartilizing for rice field.