Abstract: A substrate processing system includes: a process chamber that performs a semiconductor process on a substrate; a first oxygen supply unit; a first chamber that receives a gas containing oxygen (O2) from the first oxygen supply unit, receives exhaust gases discharged from the process chamber, and oxidizes the exhaust gas using the oxygen supplied from the first oxygen supply unit; a second chamber connected to the first chamber, and that receives a first treatment gas from the first chamber and bums the first treatment gas; a third chamber connected to the second chamber, and that receives a second treatment gas from the second chamber and performs a wetting treatment of the second treatment gas; and a tank disposed below the first to third chambers and connected to each of the first to third chambers.