A waste gasification and melting technology has the possibility of simultaneously addressing both material recoveries from waste and landfill minimization. Gasification of municipal solid wastes (MSW) and biomass as an energy recovery method such as fixed-bed, fluidized bed, entrained or plasma gasification, has been widely researched all over the world. The plant mainly consists of an MSW charging system, a gasifier, a combustion chamber, a boiler and a flue gas cleaning system. The new waste management scheme was developed using the co-gasification system. This system processes the bottom ash from other incineration plants and/or incombustible residues from a recycling center with MSW using the Direct Melting System (DMS) technology and recycles the inert materials as slag and metal. One of the important factors for the operating conditions of the DMS technology is the moisture contents of the waste processed. The slag and metal produced from the DMS are recycled completely, with reference to recycling conditions in Japan.