NOVELTY - The aeration composting system comprises: a housing structure having a top, which is open to put a fermented or aged fertilizer as raw material into the composting system; an ammonia concentration sensor and a hydrogen sulfide concentration sensor installed on inner portion of the composting system; a control device for generating a control signal to discharge a gas into the composting system; a blower device for supplying an air to the composting system to absorb the gas; and a leachate storage tank for storing the gas discharged from the composting system and leachate.    USE - The aeration composting system is useful for absorbing bad odor gas and toxic gas comprising ammonia and hydrogen sulfide from wastes comprising straw, weeds and fallen leaves.    ADVANTAGE - The aeration composting system effectively and simply absorbs the bad odor gas and the toxic gas from the wastes in a real-time manner.    DETAILED DESCRIPTION - The aeration composting system comprises: a housing structure having a top, which is open to put a fermented or aged fertilizer as raw material into the composting system; an ammonia concentration sensor and a hydrogen sulfide concentration sensor installed on inner portion of the composting system; a control device for generating a control signal to discharge a gas into the composting system; a blower device for supplying an air to the composting system under atmospheric pressure to absorb the gas; and a leachate storage tank for storing the gas discharged from the composting system and leachate. The air is introduced into the composting system through an air nozzle pipe at below a certain level when one of the ammonia concentration and the hydrogen sulfide concentration exceeds the predetermined concentration range. A bad odor gas concentration of the gas is discharged through the air nozzle pipe. The system further comprises: a moisture content sensor for controlling moisture level of the raw material, where the moisture content sensor sprays the leachate to the raw material when the moisture level of the raw material becomes lower than its predetermined range that is less than 50%; a gas exhaust pipe connected with a diffuser of the leachate storage tank; a bypass piping arrangement in which the air nozzle pipe is connected with a gas suction valve; an air supply pipe connected with the air nozzle pipe; an air nozzle tubing mounted on an air inlet port of the blower device; and an air supplying valve respectively connected at outside of the gas suction valve. The concentration of ammonia is 1 mg/l. The concentration of hydrogen sulfide is 20 mg/l. The gas suction valve is connected with a lower part of the system. The control device is connected with a power off-on cycle so that the air flowed via the air supplying valve is closed or opened. The bad odor gas concentration of the gas is 400-600 l/minute (preferably 600 l/minute), and is processed in the power off-on cycle for 30 minutes.