NOVELTY - Air dried powder composting involves using three cyclones and a dehydration apparatus, and storing sludge in a depot. The dehydration apparatus removes moisture of sludge from 97% to 80% by dehydration process to obtain dehydration cake. Moisture content of the dehydration cake is further reduced to 60% through an air drier and spherical particles are produced by using air drying process. The spherical particles are fermented under anaerobic condition. The spherical particles are supplied with high pressure to air drying process by an air ejector and heated by a blower to produce compost.    USE - Method for composting dried air-powder of human or livestock manure sludge using air drying system.    ADVANTAGE - The air-dried powder composting method enables to provide compost of improved quality in short time by preventing loss of organic compound, where the obtained compost has improved particle size and reduced carbon-nitrogen ratio, salinity and moisture contents, thus organic content of the compost is increased and sludge content is reduced.    DETAILED DESCRIPTION - Air dried powder composting involves using three cyclones and a dehydration apparatus, and storing sludge in a depot. The dehydration apparatus removes moisture of sludge from 97% to 80% by dehydration process to obtain dehydration cake. Moisture content of the dehydration cake is further reduced to 60% through an air drier and spherical particles are produced by using air drying process. The spherical particles are fermented under anaerobic condition. The spherical particles are supplied with high pressure to air drying process by an air ejector and heated by a blower to produce compost. The spherical particles of sludge are supplied to former cyclone through the air ejector, where particles float in air. Moisture of sludge is vaporized due to pulverization of sludge particles by collision between sludge particles and air. The spherical particles are rotated, flown and adhered due to aggregation and coagulation, and then transferred into latter cyclone. The spherical particles of sludge are supplied to third cyclone, where gas including moisture is released into atmosphere. The spherical particles are collected in a recovery can in the form of air dried powder. A microorganism supply line is connected to former cyclone for supplying effective microorganism, where microorganism grows inside the spherical particles of the sludge. The air ejector is connected to the blower through a distributor.