New requirements on the JET Exhaust Detritiation System (ED) for low concentration tritium removal from air during extended periods of time caused concern about system life and reliability: re-furbishment of the JET divertor after DT operations by means of remote handling or an intervention on a neutral injector used for tritium injection may require 180 ED dryer regeneration cycles during a three month period. Several possibilities were investigated with the aim of additional humidity removal to reduce the dryer loading rate. The selected system, based on an oil free rotary screw air compressor in combination with a continuously regenerated molecular sieve drum dryer is described in detail. Having recognised the advantage of operating future atmosphere detritiation systems entirely at elevated pressure, we propose to apply recovery of the thermal and mechanical energy of the compressed air. A compact and economical system based on this method is described in detai