下水汚泥の高温好気処理法における熱収支に関する研究

Abstract

The purpose of this study is to assess the biodegradation rate from the energy balance in the thermophilic oxic process, which is applied to treat the excess sludge, thickened sludge and dewatered sludge cake produced in the wastewater treatment plant. The readily degradable organic matter contained in the sludge was degraded firstly at the thermophilic oxic process according to the temperature curve, on which the temperature rises quickly at the test of sewage sludge added with waste food oil. From the energy budget, about 55-63% of heat produced from bioreaction was used to evaporate water ; around 23-30% of heat produced was used to prevent heat loss. The relationship between organic load and water content was certified, and the addition of energy source is important for the treatment of sewage sludge by the thermophilic oxic process. From the rates of the heat produced from bioreaction to the total calories of organic matter added in these tests, which were varied from 1.02, 1.07 and 0.60, respectively, it is clear that the excess sludge and thickened sludge were degraded more efficiently than dewatered sludge cake. The determination of energy balance could be used to assess the biodegradation rate of organic matter in the thermophilic oxic process.