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.

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 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.

Underdrain units in a sand medium or dual medium filtration system include efficient air, water and combined air/water cleaning. Air, water or both are delivered in backflow direction from a very low position on the underdrain unit, as well as water from a higher position, so as to effectively remove blocking contaminants on the outside the underdrain unit and in the surrounding filter media.

A method of installing a filter underdrain system includes: positioning a grout pad on a filter floor; positioning an underdrain block onto the grout pad such that the grout pad is displaced when the underdrain block is positioned on the grout pad; and inserting filler grout around the underdrain block.

A method of installing a filter underdrain system includes: positioning a grout pad on a filter floor; positioning an underdrain block onto the grout pad such that the grout pad is displaced when the underdrain block is positioned on the grout pad; and inserting filler grout around the underdrain block.

A capture unit for use with an antimicrobial application unit may include an upstream filter and a downstream filter. The upstream filter may be positioned to receive effluent from the application unit and to filter solid components from the effluent. The resultant upstream effluent filtrate may then be passed downstream to the downstream filter. The downstream filter may be used to filter an antimicrobial component from the upstream effluent filtrate and the resultant downstream effluent filtrate may be suitable for disposal as wastewater discharge. The antimicrobial is preferably a quaternary ammonium compound, is more preferably an alkylpyridinium chloride, and is most preferably cetylpyridinium chloride.

A capture unit for use with an antimicrobial application unit may include an upstream filter and a downstream filter. The upstream filter may be positioned to receive effluent from the application unit and to filter solid components from the effluent. The resultant upstream effluent filtrate may then be passed downstream to the downstream filter. The downstream filter may be used to filter an antimicrobial component from the upstream effluent filtrate and the resultant downstream effluent filtrate may be suitable for disposal as wastewater discharge. The antimicrobial is preferably a quaternary ammonium compound, is more preferably an alkylpyridinium chloride, and is most preferably cetylpyridinium chloride.

A support grid assembly for use in a vessel. The support grid assembly includes panels each including a first wall including a media-supporting screen and a second wall to be supported by the vessel wall inner surface. A manifold is coupled to the panels and is in hydraulic communication with vessel outlet. The manifold and the panels permit fluid to flow through the screen in each panel, through the panels, into the manifold, and through the manifold to the outlet of the vessel, as well as in the reverse direction. At least a portion of the first wall may slope downward toward the manifold, and at least a portion of the second wall may form a bottom surface that is curved to substantially conform to a curvature of the vessel wall inner surface. The panels may be arranged in a circular configuration extending radially from the manifold.

A support grid assembly for use in a vessel. The support grid assembly includes panels each including a first wall including a media-supporting screen and a second wall to be supported by the vessel wall inner surface. A manifold is coupled to the panels and is in hydraulic communication with vessel outlet. The manifold and the panels permit fluid to flow through the screen in each panel, through the panels, into the manifold, and through the manifold to the outlet of the vessel, as well as in the reverse direction. At least a portion of the first wall may slope downward toward the manifold, and at least a portion of the second wall may form a bottom surface that is curved to substantially conform to a curvature of the vessel wall inner surface. The panels may be arranged in a circular configuration extending radially from the manifold.