REDUCTION OF DIOXIN EMISSION ON START UP AND SHUT DOWN AT BATCH-OPERATIONAL MSW INCINERATION PLANT

At present, it is known that dioxin emission can be controlled at a low level by (1) implementing stable and optimum combustion, (2) maintaining lower gas temperature through dust collectors and (3) enhancing the efficiency of dust collectors when the combustion in a furnace is steady and/or in a normal operation. There are approximately 3,000 local communities in Japan. Many localities have the responsibility of managing their wastes properly discharged from their own district, many of them have their own incineration plants of which capacities are small-scale with batch-type operation. 1,500 incineration plants, among approximate 1,900 plants in Japan, are operated without continuous operation. 1 The furnaces in those plants are started up and shut down daily. Since the combustion is unstable during such periods, there are possibilities for dioxins and other unburnt substances being emitted into the atmosphere. This paper describes the current situation regarding the dioxin emissions at start up and shut down of small furnaces and methods of controlling such emissions.