The activated sludge process is widely used for treating sewage and organic wastewater because of its excellent cost effectiveness and efficiency. The biggest drawback to this process, however, is the formation of excess sludge that is attributable to sludge components in sewage/wastewater. We have developed a system for reducing the volume of excess sludge with the use of an ultra super sonic steam dryer. Through the promotion of this excellent technology, we are thus poised to contribute to the creation and development of a recycling-oriented society in the 21st century.