Abstract: A modular container which includes a housing frame containing particulate material through which contaminated liquid is passed for purposes of purification. The container includes flow distribution members which are secured within the housing frame for dispersing flow of the incoming contaminated liquid equally throughout the particulate material. Containment members formed of a fibrous material are bonded to the flow distribution members to constrain the particulate material within the housing frame. The containment members are porous to permit passage of the liquid therethrough but of sufficient density to retain the particulate material within a chamber of the housing frame. Upper and lower cover members are hermetically sealed to the housing frame and include conduits to permit insertion of contaminated liquid and egress of purified liquid after it has passed through the particulate material.