Abstract: A filter for a filter vessel which converts the filter vessel to use disposable filters for removing hazardous particulate matter from an aqueous flow. The filter includes a rigid support housing having an input passage for the aqueous flow, an exit passage for the aqueous flow, an internal sealing surface and a locking seal located adjacent to the input passage to securingly engage the filter vessel for the aqueous flow. The invention also includes a sleeveless disposable filter cartridge. The cartridge includes a flexible filtering medium having first and second ends. A terminal seal is affixed to the first end of the filtering medium for sealing engagement with the filter vessel and a wall seal on the second end of the filtering medium for engagement with the internal sealing surface of the support housing.