A filtration module (10) is provided which includes a manifold (12), a filter cartridge (16) and a bowl (14) which houses the filter cartridge (16). The filter cartridge (16) and bowl (14) are connected to each other by a key (30) which is secured to flat surfaces (38) on the cartridge (16) to form a unitary construction. The filter cartridge (16) and bowl (14) are in fluid communication with the manifold (12) in a manner which prevents mixing of a fluid feed to the module (10) and a permeate removed from the module (10).