This disclosure relates to filtration screens for use in a backwashable granular media bed filtration system. Drop-in retrofit kits for a backwashable granular media bed filtration system comprising one or more filtrations screens are provided herein. Such screens and kits can comprise a media support screen, a backwash filter screen, or a combination thereof. The kit can further comprise an agitator element comprising an impeller having vanes in which the impeller vane surfaces are coated with an abrasion resistant material. Associated filtration systems and processes are also described herein.

An apparatus for removing impurities from water and/or wastewater and a method of installing a fluid distribution system in the apparatus. In the most preferred form of the invention, the fluid distribution system is an air scour system for directing air through the filter bed to assist in cleaning of the filter bed to remove impurities trapped in the filter bed during a service run. In the most preferred form, the method of installing the fluid distribution system in the filter bed is performed by imparting a force to the filter bed to permit the fluid distribution system to be installed in the filter bed without removing media. The fluid distribution system is preferably configured to permit the fluid distribution system to be readily installed in the filter bed and at an optimum orientation.

An apparatus for cleaning pool or spa filters includes: a housing; a turntable assembly in the housing, the turntable assembly configured to receive a filter thereon; and a fluid assembly on the housing configured to receive liquid from a liquid source. The fluid assembly includes: a spin jet configured to spray the liquid on the turntable such that the turntable and the filter thereon spin; and at least one power jet configured to spray the liquid on and/or through the filter while the turntable assembly and the filter spin.

Embodiments of the present disclosure describe filter agitators, filtration units comprising the filter agitators, methods of using the filter agitators, and the like. In certain embodiments, the filter agitators comprise a plurality of first fins extending outwardly from a central vertical axis and arranged in a plane oriented substantially perpendicular to the central vertical axis, wherein the plurality of first fins is configured to promote laminar flow of a fluid flowing in a first direction and induce turbulent flow of a fluid flowing in a second direction; and optionally a plurality of second fins positioned above the plurality of first fins and extending outwardly from the central vertical axis, wherein the plurality of second fins is configured to induce or further induce turbulent flow.

A filtration apparatus includes a filtration tank; a layer of filtration media that filters supplied raw water by passing the raw water therethrough within the interior of the filtration tank; and a screw cleansing mechanism having a cylindrical outer cylinder which is provided within the filtration tank in a vertical orientation, a spiral shaped screw which is provided such that the long axis thereof extends in the longitudinal direction of the outer cylinder, and a screw driving member for rotating the screw, that scrubs and cleans filtration media by rotating the screw. The screw is in the shape of a coil spring.

A filter is provided including a vessel having an input positioned near the top of the vessel for contaminated fluid; the vessel containing media; a drain screen; a propeller rotatable on a drive shaft extending downwardly from the top of the vessel; a deflector plate below the drain screen to impel media outwardly from the center of the vessel; a plurality of baffles positioned on side walls of the vessel; and a drain to remove fluid from the vessel.

A filter is provided including a vessel having an input positioned near the top of the vessel for contaminated fluid; the vessel containing media; a drain screen; a propeller rotatable on a drive shaft extending downwardly from the top of the vessel; a deflector plate below the drain screen to impel media outwardly from the center of the vessel; a plurality of baffles positioned on side walls of the vessel; and a drain to remove fluid from the vessel.

A filtration apparatus includes a filtration tank; a layer of filtration media that filters supplied raw water by passing the raw water therethrough within the interior of the filtration tank; and a screw cleansing mechanism having a cylindrical outer cylinder which is provided within the filtration tank in a vertical orientation, a spiral shaped screw which is provided such that the long axis thereof extends in the longitudinal direction of the outer cylinder, and a screw driving member for rotating the screw, that scrubs and cleans filtration media by rotating the screw. The screw is in the shape of a coil spring.

Embodiments of the present disclosure describe filter agitators, filtration units comprising the filter agitators, methods of using the filter agitators, and the like. In certain embodiments, the filter agitators comprise a plurality of first fins extending outwardly from a central vertical axis and arranged in a plane oriented substantially perpendicular to the central vertical axis, wherein the plurality of first fins is configured to promote laminar flow of a fluid flowing in a first direction and induce turbulent flow of a fluid flowing in a second direction; and optionally a plurality of second fins positioned above the plurality of first fins and extending outwardly from the central vertical axis, wherein the plurality of second fins is configured to induce or further induce turbulent flow.

A filter is provided including a vessel having an input positioned near the top of the vessel for contaminated fluid; the vessel containing media; a drain screen; a propeller rotatable on a drive shaft extending downwardly from the top of the vessel; a deflector plate below the drain screen to impel media outwardly from the center of the vessel; a plurality of baffles positioned on side walls of the vessel; and a drain to remove fluid from the vessel.