A filtration system has at least one underdrain lateral, a flume, and at least one metering plate. The metering plate includes a plate member with at least one opening configured to receive liquid or gas therethrough at a first flow rate during a backwash function and is configured to receive liquid or gas therethrough at a second, lower flow rate during filtration. A method of metering gas into a filtration system with a metering plate is also disclosed. The metering plate allows gas to flow into each underdrain lateral at two very different flow rates.

An apparatus for use in a filter system for filtering water or wastewater. The apparatus preferably includes at least one underdrain lateral having at least an inner chamber, a first outer chamber and a second outer chamber. The first outer chamber and the second outer chamber are preferably in fluid communication with the inner chamber. The inner chamber, the first outer chamber and the second outer chamber are preferably formed by an inner liner and an outer liner. The outer liner is a separate piece from the inner liner and surrounds the inner liner. The inner chamber is preferably configured to simultaneously receive a liquid and a gas during a washing procedure including simultaneous use of a liquid and gas to clean a filter bed to create a liquid and gas interface in the inner chamber.

An apparatus for use in a filter system for filtering water or wastewater. The apparatus preferably includes at least one underdrain lateral having at least an inner chamber, a first outer chamber and a second outer chamber. The first outer chamber and the second outer chamber are preferably in fluid communication with the inner chamber. The inner chamber, the first outer chamber and the second outer chamber are preferably formed by an inner liner and an outer liner. The outer liner is a separate piece from the inner liner and surrounds the inner liner. The inner chamber is preferably configured to simultaneously receive a liquid and a gas during a washing procedure including simultaneous use of a liquid and gas to clean a filter bed to create a liquid and gas interface in the inner chamber.

A modular underdrain system is disclosed. The modular underdrain system may comprise an intermediate modular component having a first peripheral side including a first mating portion and a second peripheral side including a second mating portion. The second mating portion may be sized and shaped to engage with a first mating portion of an adjacent modular component. A modular component chamber may be bounded by an underdrain floor side and an internal side. The underdrain floor side may comprise a plurality of slots. The metering pipe is sized to be positioned within a metering pipe opening in the internal side with a distributor head positioned within the modular component chamber. The metering pipe may comprise a set of one or more remote orifices and a set of one or more proximate orifices.

A modular underdrain system is disclosed. The modular underdrain system may comprise an intermediate modular component having a first peripheral side including a first mating portion and a second peripheral side including a second mating portion. The second mating portion may be sized and shaped to engage with a first mating portion of an adjacent modular component. A modular component chamber may be bounded by an underdrain floor side and an internal side. The underdrain floor side may comprise a plurality of slots. The metering pipe is sized to be positioned within a metering pipe opening in the internal side with a distributor head positioned within the modular component chamber. The metering pipe may comprise a set of one or more remote orifices and a set of one or more proximate orifices.

Locally backwashing portions of filter media allows a simple and effective design of intake and pretreatment units, as well as their integration. An enclosure is used to limit portions of filter media and backwash them locally by suction, utilizing filtered water from adjacent filter media as the back wash water. Wastewater is produced at small amounts that allows efficient sludge treatment. This design enables water pretreatment at the intake unit, simplifying overall plant design and preventing damage to organisms living outside the intake unit.

Locally backwashing portions of filter media allows a simple and effective design of intake and pretreatment units, as well as their integration. An enclosure is used to limit portions of filter media and backwash them locally by suction, utilizing filtered water from adjacent filter media as the back wash water. Wastewater is produced at small amounts that allows efficient sludge treatment. This design enables water pretreatment at the intake unit, simplifying overall plant design and preventing damage to organisms living outside the intake unit.

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 block for filtering water includes a top wall, a bottom wall, and two side walls connecting the top wall to the bottom wall to define an internal chamber. The bottom wall contains a plurality of orifices that allow liquid and solid materials to enter and exit the internal chamber. An underdrain filtering system can be formed by securing an underdrain lateral, which is formed from one or a plurality of underdrain blocks, to a filter floor. Also included is a method of preparing an underdrain lateral for providing even distribution of backwash water along the underdrain lateral and a method of validating even distribution of backwash water across an underdrain lateral.

An underdrain block for filtering water includes a top wall, a bottom wall, and two side walls connecting the top wall to the bottom wall to define an internal chamber. The bottom wall contains a plurality of orifices that allow liquid and solid materials to enter and exit the internal chamber. An underdrain filtering system can be formed by securing an underdrain lateral, which is formed from one or a plurality of underdrain blocks, to a filter floor. Also included is a method of preparing an underdrain lateral for providing even distribution of backwash water along the underdrain lateral and a method of validating even distribution of backwash water across an underdrain lateral.