PURPOSE: To incinerate waste without using large amount of water by collecting fly carbon by a multicyclone, lowering the temperature of collected smoke gas, re-heating the purified smoke gas, sedimenting the fly carbon collected by a rotating scraper and water treating the coagulate obtained by cooling the flowing in smoke gas.

CONSTITUTION: Most of the fly carbon are collected from the smoke gas by the multicyclone. The collected smoke gas from the multicyclone is cooled by a heat exchanger, the speed and the temperature of the smoke gas are lowered in a gravity room 20 and the smoke gas is purified. The fly carbon is separated from the smoke gas by gravity and sedimented, collected by scraping by a scraper 25 and removed, and transferred by an extraction pipe 29. The remaining smoke gas is introduced into a cooling room and condensate of it by cooling is extracted, collected by a capture reservoir 35 arranged on a floor, transferred by a pump 36 to a water treatment facility and removed in the form of liquid. Large amount of water is not required for the purifying operation.