Abstract
The characteristics of solubilization of excess sludge by hydrothermal reaction and the biodegradability of hydrothermally treated sludge were investigated. The effects of the reaction temperature, time and sludge concentration were evaluated. Experimental results suggested that (1) the hydrothermal reaction of the excess sludge was successive reaction, the solubilization of the sludge followed by the gasification, (2) the reaction time was shorten with the temperature increasing, (3) about 85% of the sludge was solubilized above 150°C (0.6 MPa), (4) the depolymerization of the sludge cell was advanced with the temperature increasing, while the biodegradability was slightly increased, (5) the mixture of the hydrothermally treated sludge and the artificial sewage was biologically destructed in about 6 hours by acclimated microorganism.
