Abstract: 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.

Abstract: A method of distributing gas and liquid through an underdrain system includes: a) positioning an underdrain system on a filter floor, the underdrain system comprising at least one underdrain block and filter media positioned on top of the underdrain block; b) distributing gas sufficiently evenly through the underdrain system at a rate of less than 2 scfm/ft2 by distributing a liquid at a rate of less than 2 gpm/ft2 concurrently with the gas; c) increasing the distribution rate of the liquid, or increasing the distribution rate of the liquid and the distribution rate of the gas; d) stopping the distribution of gas; e) further increasing the distribution rate of the liquid; and f) decreasing the distribution rate of the liquid. A method of distributing gas and liquid during an upflow filtration mode is also included.

Abstract: 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.

Abstract: 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.

Abstract: An underdrain system for transferring forces and directing flow includes at least one underdrain block having a top wall, a bottom wall, and two side walls connecting the top wall to the bottom wall to define a block interior. An insert is disposed in the interior of the underdrain block. The insert includes force-transmitting buttresses spaced along an exterior of the insert that contacts the two side walls of the underdrain block and act to transfer downward forces acting on the top wall of the underdrain block and internal fluid forces acting on the insert to the side walls of the underdrain block. The force-transmitting buttresses can also direct hydraulic flow.

Abstract: The present invention relates to a method and system for monitoring and controlling the process train of ozonation and biologically aerated filtration used in water and wastewater treatment. The process monitoring and control can be achieved by online measurement of UV/Vis absorption at one or multiple wavelengths and oxidation/reduction potential values which are compared to predetermined UV absorption and oxidation/reduction values. The air and ozone dosage of the effluent are then adjusted based on the measured values of UV/Vis absorption and oxidation/reduction potential of the effluent.

Abstract: A filter system for filtering particles from a liquid includes an underdrain assembly having an underdrain defining at least one underdrain chamber and a media retainer assembly. The media retainer assembly includes an upper filter media retainer plate defining a plurality of hopper-shaped cavities and a lower filter media retainer plate defining a plurality of hopper-shaped cavities corresponding to the plurality of hopper-shaped cavities on the upper plate. The plates are in a nested arrangement such that the hopper-shaped cavities on the upper plate are in alignment with the corresponding plurality of hopper-shaped cavities on the lower plate to define a plurality of passages therebetween and allow for the passage of the liquid while preventing the passage of a filter media. During a backwash operation, the upper and lower plates are relatively moveable such that the backwash fluid releases any particles lodged in the passages between the plates.

Abstract: The present invention relates to a method and system for monitoring and controlling the process train of ozonation and biologically aerated filtration used in water and wastewater treatment. The process monitoring and control can be achieved by online measurement of UV/Vis absorption at one or multiple wavelengths and oxidation/reduction potential values which are compared to predetermined UV absorption and oxidation/reduction values. The air and ozone dosage of the effluent are then adjusted based on the measured values of UV/Vis absorption and oxidation/reduction potential of the effluent.

Abstract: 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.

Abstract: A dual parallel underdrain lateral for use in a filtration system having a filtration media includes a primary conduit extending along the underdrain lateral, which has a plurality of metering orifices for providing gas and liquid thereby; a secondary conduit, where the secondary conduit has a plurality of dispersion apertures in an upper side thereof to deliver the gas and liquid from the secondary conduit to the filtration media; and at least one gas conduit extending along the underdrain lateral, where the at least one gas conduit is connected to a gas source and is configured to provide the gas from the gas source directly to the primary conduit, or the secondary conduit, or any combination thereof.

Abstract: An underdrain system for transferring forces and directing flow includes at least one underdrain block having a top wall, a bottom wall, and two side walls connecting the top wall to the bottom wall to define a block interior. An insert is disposed in the interior of the underdrain block. The insert includes force-transmitting buttresses spaced along an exterior of the insert that contacts the two side walls of the underdrain block and act to transfer downward forces acting on the top wall of the underdrain block and internal fluid forces acting on the insert to the side walls of the underdrain block. The force-transmitting buttresses can also direct hydraulic flow.

Abstract: A method of distributing gas and liquid through an underdrain system includes: a) positioning an underdrain system on a filter floor, the underdrain system comprising at least one underdrain block and filter media positioned on top of the underdrain block; b) distributing gas sufficiently evenly through the underdrain system at a rate of less than 2 scfm/ft2 by distributing a liquid at a rate of less than 2 gpm/ft2 concurrently with the gas; c) increasing the distribution rate of the liquid, or increasing the distribution rate of the liquid and the distribution rate of the gas; d) stopping the distribution of gas; e) further increasing the distribution rate of the liquid; and f) decreasing the distribution rate of the liquid. A method of distributing gas and liquid during an upflow filtration mode is also included.

Abstract: A filter system for filtering particles from a liquid includes an underdrain assembly having an underdrain defining at least one underdrain chamber and a media retainer assembly. The media retainer assembly includes an upper filter media retainer plate defining a plurality of hopper-shaped cavities and a lower filter media retainer plate defining a plurality of hopper-shaped cavities corresponding to the plurality of hopper-shaped cavities on the upper plate. The plates are in a nested arrangement such that the hopper-shaped cavities on the upper plate are in alignment with the corresponding plurality of hopper-shaped cavities on the lower plate to define a plurality of passages therebetween and allow for the passage of the liquid while preventing the passage of a filter media. During a backwash operation, the upper and lower plates are relatively moveable such that the backwash fluid releases any particles lodged in the passages between the plates.