Abstract
The amount of sewage sludge produced in municipal wastewater treatment plants in Japan increases with the increasing population every year. Hence, the introduction of the solubilization of sewage sludge is being hastened. In many solubilization processes, high-speed rotary disk process has became the center of attention for the characteristics of easier control, maintenance and expectation of cost reduction. Therefore, in this study, high-speed rotary disk process was applied to solubilization of excess sludge from a sewage plant of Ube city, Yamaguchi prefecture to examine optimum operational conditions. As the results, with anaerobic treatment, the solubilized sludge from high-speed rotary disk process could shorten digestion time until 10 days. And more, applying the solubilized sludge from high-speed rotary disk process in activated sludge process, the excess sludge produced from the settle tank could be reduced 60 %. In addition, when comparing with other solubilization methods (ultrasonic process and subcritical water process) to evaluate utility of high-speed rotary disk process, as the results, electionic consumption of high-speed rotary disk process was superior to other solubilization methods.
