Sewage treatment plants treat domestic wastewater and produce sewage sludge at the final stage of the treatment. Incineration is one of the methods of disposal for reducing the volume of sewage sludge. In response to a shortage of dump yards due to a growing awareness of environmental conservation, and tightening regulations against industrial wastes, however, treatment plants are increasingly required to have less of a burden on the environment. Moreover, their cost effectiveness is receiving widespread attention because of recent financial pressures on municipalities. We are now testing a "high-efficiency system for disposal of sewage sludge" that is designed to detoxify the sludge, and reduce construction and maintenance costs. This system dewaters sludge considerably, and incinerates dewatered cake with low moisture content, thereby reducing consumption of auxiliary fuels such as heavy oil, and emissions associated with it. In addition, it aims to downsize the incineration system itself, cut down maintenance costs dramatically, and reduce the burden on the environment.