Waste water from the food waste were thrown in the sea in order to be used fish food. But this process must be changed before 2012, because waste water must be changed to useful materials in the land. We proposed the method to separate condensate water from a high-temperature and high-humidity air stream and discharge the condensate water having passed through a purifying operation, while utilizing the residual air stream as burning air required for drying and carbonization of waste material.