Abstract: An integrated environmental control (IEC) system includes a decontamination Pressure Swing Adsorption (PSA) system in which a contaminated decontamination bed is purged through a purge exhaust duct and subsequently dumped overboard through a purge ejector. The energy from a high pressure drain duct serves as the primary motive force for the purge ejector to create a sub-atmospheric region therein and reduce back pressure upon the PSA filtration system. The reduced back pressure creates additional pressure drop across the PSA filtration system which improves performance. Risk of the purge exhaust duct and the purge ejector freezing in a low temperature environment is further minimized by mixing the purge exhaust with the relatively warmer high pressure drains.