Abstract
In recent years, the amount of excess sludge increases with the spread of sewage treatment equipment, and there need methods of reduction and recycling excess sludge. We developed hydrothermal pre-treatment that promotes anaerobic digestion of excess sludge. As a results of experiments .hydrothermal treatment and digestion, we make clear the best conditions to improve digestion, temperature 150-170℃, pressure 0.95MPa, and air supply of very small quantity. Furthermore, a result of trial calculation in case of applying to digestive process shows that hydrothermal pre-treatment reduce residue and produce electricity largely than usual, the reduction rate of sludge is above 40%, and the production rate of electricity is above 70%.
