Specifying internals in sour water strippersâPart 1 Specifying internals in sour water strippersâPart 1 A sour water stripper (SWS) system is a common process in petroleum refineries and other processes where hydrogen sulfide is present. A sour water stripper (SWS) system is a common process in petroleum refineries and other processes where hydrogen sulfide (H 2S) is present. While not a revenue generator, the sour water treating system is a critical unit operation and can be a significant bottleneck to facility production rates if it is not adequately sized or if it is forced to op...