Abstract: A system (10) comprising multiple units (40a-40h) and method for filtration of wastewater (20) is disclosed. Simultaneous denitrification of a single filter unit and normal filtration of the remaining filter units is provided for. Separate flow control systems (36) are described.

Abstract: A system (10) comprising multiple units (40a-40h) and method for filtration of wastewater (20) is disclosed. Simultaneous denitrification of a single filter unit and normal filtration of the remaining filter units is provided for. Separate flow control systems (36) are described.

Abstract: A method for removal of solids in a water treatment system having multiple filters, each filter comprising an air backwash system and a water backwash system, comprising a series of steps to enable two filters to be in some stage of the backwash process at the same time thereby reducing the time the filter is out of service. The continuous cycling of the backwash method is characterized by a continuous cycle of backwashing that backwashes two filters simultaneously. The backwashing method requires three steps, an air-only backwash, an air/water bashwash and a water-only or rinse backwash. In this method, as one filter is at the water-only backwash stage, the backwash cycle of a second filter is started so that the second filter is air/water backwashed while the first filter is at the water-only backwashed stage.

Abstract: A method for removal of solids in a water treatment system having multiple filters, each filter comprising an air backwash system and a water backwash system, comprising a series of steps to enable two filters to be in some stage of the backwash process at the same time thereby reducing the time the filter is out of service. The continuous cycling of the backwash method is characterized by a continuous cycle of backwashing that backwashes two filters simultaneously. The backwashing method requires three steps, an air-only backwash, an air/water bashwash and a water-only or rinse backwash. In this method, as one filter is at the water-only backwash stage, the backwash cycle of a second filter is started so that the second filter is air/water backwashed while the first filter is at the water-only backwashed stage.

Abstract: A filter media support system that reduces media clogging and head loss in granular filtration systems by providing a layered porous plate. The porous plate can have multiple layers of fine sized and coarse sized pores. The porous plate is positioned between the media and the filter bottom. The filter media support system is securely anchored to the infrastructure of the underdrain system thereby inhibiting media penetration of the filter bottom and avoiding seal failures. The infrastructure can be air lateral piping fitted beneath the underdrain blocks of the support system. The anchors can be secured to pipe clamps circumscribing the air laterals.

Abstract: A method for retrofitting a gravity filter with a porous plate filter media support that increase filter production by increasing the depth of the media, allows installation of an air backwash system in filters having a monolithic underdrain system, and reduces turbulence and head loss in granular filtration systems. The method comprising removal of existing media and gravel media-support bed and installation of a porous plate media support. The porous plate can have multiple layers of fine sized and coarse sized pores. The porous plate is positioned between the media and the filter bottom and is securely anchored to the monolithic underdrain system thereby allowing uniform distribution of backwash, inhibiting media penetration of the filter bottom and avoiding seal failures.

Abstract: An underdrain block for a filter media system for supporting the filter media and distributing air and water backwash. The underdrain block comprising a top wall, a bottom wall and two side walls forming an open ended interior. Interior walls, known as lateral separation walls, divide the interior of the block into primary and secondary laterals. When the blocks are laid end to end, the laterals form a common distribution conduit for the transport of air and water backwash. The lateral separation walls can be angular or curved. Curved walls and specifically angled walls increase the area of the laterals. The spacing of the blocks can be approximately 18 inches and the height approximately 8 inches. The underdrain blocks are interlocking to form conduits of up to 40 feet in length.

Abstract: A method for controlling the addition of liquid treatment chemicals by automatic dose control. The calculation of the amount of chemical to be dosed into the system combines signals from a liquid flow meter, an influent chemical concentration analyzer and/or an effluent chemical concentration analyzer. The signals are directed to a computerized chemical dose controller that analyzes and adjusts the data from the signals and generates an output signal that controls the chemical dosing mechanisms. For example, the automatic dose control method encompasses the ability to set maximum positive and negative limits of control action as well as the ability to automatically or manually control the reset period necessary to allow previous changes to propagate through the system and be displayed at the effluent sensor thereby improving the dosing of the chemical during treatment of a liquid, wastewater for example.

Abstract: A grout-gripping anchor for an underdrain block to be grouted to a filter floor is disclosed. Underdrain blocks have ribs extending outwardly from the exterior walls. The anchor is formed at the distant end of ribs positioned on the bottom exterior wall. The end of the rib widens to form one or more flanges or ledges so that grout covers the ledge when the underdrain block is grouted onto the filter floor. The anchor can be comprised of various shapes, including wedge-shape, rectangular shape or donut shaped.