ESTIMATION OF ENERGY SAVING FOR MELTING PROCESS ON SEWAGE-SLUDGE

The possible volume reduction and stabilization of the sewage sludge associated with the melting process are expected to be greater than with the incineration process. In addition, melted slag can be utilized. However, since the melting process requires a very high temperature to melt inorganics (ash) in the sludge, the technologies to minimize energy consumption, to establish system operation and to prolong durability of facilities should be developed. This paper discusses the auxiliary fuel consumption as follows. (1) preparation of a model that provides the auxiliary fuel consumption of the melting system on the basis of the mass and heat balances. (2) Evaluation of the auxiliary fuel consumption in the above model using the cake moisture content, the volatile solids of the cake, the dried cake moisture content and the melting temperature as parameters. (3) Examination of the operational conditions for an energy saving melting system based on the results of (1) and (2) above.