Filter cartridge construction

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