Devices and methods associated with these devices for significantly reducing or eliminating liquid (e.g., water) in a water or wastewater treatment unit above the underdrain from moving downwardly into the underdrain during an air only wash cycle of the treatment unit. The treatment unit can take many forms including but not limited to an upflow filter and a downflow filter. The treatment unit may include a filter bed having one or more layers of filter media supported by gravel above the underdrain. The treatment unit may also include an underdrain having a porous plate, slotted plate or slotted upper structure that obviates the need for gravel. Positive pressure is provided to the underdrain to overcome the downward force of the driving head in the treatment unit to significantly reduce or prevent liquid present in the treatment unit above the underdrain from moving downwardly into the underdrain.

Devices and methods associated with these devices for significantly reducing or eliminating liquid (e.g., water) in a water or wastewater treatment unit above the underdrain from moving downwardly into the underdrain during an air only wash cycle of the treatment unit. The treatment unit can take many forms including but not limited to an upflow filter and a downflow filter. The treatment unit may include a filter bed having one or more layers of filter media supported by gravel above the underdrain. The treatment unit may also include an underdrain having a porous plate, slotted plate or slotted upper structure that obviates the need for gravel. Positive pressure is provided to the underdrain to overcome the downward force of the driving head in the treatment unit to significantly reduce or prevent liquid present in the treatment unit above the underdrain from moving downwardly into the underdrain.

The invention provides structures, methods, and assemblies for bioretention systems, including tree box filters with one or more internal bypass features incorporated into the tree box filter. The invention also provides methods and additional structures that are useful for managing stormwater flow and inhibiting the flow of pollutants, debris, and other contaminants into drainage systems.

An underdrain apparatus and a method for manufacturing such apparatus are provided. The underdrain apparatus can be extruded in long sections as a unitary part. The underdrain apparatus may be extruded in various sizes, shapes, and materials. Further, the underdrain apparatus may include a passageway for transporting water to and from the filter media and/or air to the filter media. In some embodiments, apertures are formed in the underdrain apparatus during an extrusion process to provide a path between the passageway and the filter media.

An underdrain apparatus and a method for manufacturing such apparatus are provided. The underdrain apparatus can be extruded in long sections as a unitary part. The underdrain apparatus may be extruded in various sizes, shapes, and materials. Further, the underdrain apparatus may include a passageway for transporting water to and from the filter media and/or air to the filter media. In some embodiments, apertures are formed in the underdrain apparatus during an extrusion process to provide a path between the passageway and the filter media.

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.

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.

A fluid flow accessory is provided for coupling to an opening formed in a wall portion. The fluid flow accessory includes a cup having an edge configured to engage a first surface of the wall portion; and a coupling member including coupling arrangement configured for coupling to the cup and a first flange configured to be inserted through the opening in a first orientation thereof with respect to the opening, and for abutting against a second surface of the wall portion in a second orientation thereof with respect to the opening, and a fastening member protruding towards the first flange and being disposed such that in the second orientation it engages a segment of the wall portion thereby limiting the displacement of the coupling member into the first orientation.

A fluid flow accessory is provided for coupling to an opening formed in a wall portion. The fluid flow accessory includes a cup having an edge configured to engage a first surface of the wall portion; and a coupling member including coupling arrangement configured for coupling to the cup and a first flange configured to be inserted through the opening in a first orientation thereof with respect to the opening, and for abutting against a second surface of the wall portion in a second orientation thereof with respect to the opening, and a fastening member protruding towards the first flange and being disposed such that in the second orientation it engages a segment of the wall portion thereby limiting the displacement of the coupling member into the first orientation.

A filtration system includes a plurality of underdrain blocks arranged in a side-by-side configuration so as to define a gap therebetween, the gap configured to receive grout. Each underdrain block includes a top wall, a bottom wall, and a plurality of side walls connecting the top wall and the bottom wall. A grout bridge is arranged in the gap between adjacent underdrain blocks so as to form a grout seal between the grout bridge and adjacent side walls of the adjacent underdrain blocks. The adjacent sidewalls each include a rib, each rib defining a slot. The grout bridge is arranged in adjacent slots of the adjacent sidewalls of the adjacent underdrain blocks. A method of arranging a filtration system and a grout bridge are also disclosed.