Sludge melting furnaces have been applied recently to the treatment of a great deal of sludge generated from the sewage treatment plant. In this report, an explanation is provided of the history of system introduction, outline of treatment flow, sludge properties, operation results and effective utilization of slag generated at the reflector melting furnace, which began operation in July 1988 at the Futakami Sewage Treatment Plant in Toyama Prefecture. The melting furnace almost totally satisfies the needs of its design, and the properties of the generated melted slag exhibit the features that fully enable its effective utilization.