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.

A portable pool filter cleaning assembly is configured to retain a pool filter on support rod and allow the pool filter to spin from a spray of water. The spinning filter releases debris from the filter surface through centrifugal force. The assembly has drainage features to ensure proper drainage of water collected within the interior of the pool filter and enable proper spinning from the spray of water. The assembly utilizes a support rod with a bottom filter retainer that is conical in shape for engaging with the pool filter aperture. The bottom filter retainer may further have a bearing that enables the pool filter to rotate freely about the rod with very little force. The assembly may include a stand for securing the support rod on a hard surface, such as concrete or on an uneven lawn surface.

A combined water aeration and filtration unit (WAFU), having a tank with a vent section at a top of said WAFU and above an aeration section above a filtration section at a bottom of said WAFU. The vent section has one or more demisters and one or more vents for detraining water and providing a dry air exit from said WAFU. The air section has a water inlet ending in a spray nozzle near the top of the aeration section to turn incoming dirty water into water droplets and a forced air blower on a side or top of the aeration section for blowing air through said water droplets in rate sufficient to remove volatile organic compounds and precipitate manganese and iron. The aeration section also has one or more annular rings or partially annular baffles on an inside wall of the tank to force water from said inside wall into an interior of the tank. Thus, no water escapes aeration. A backwash collection trough and backwash water outlet are positioned above the filtration section for removing dirty backwash water from the unit. The filtration section has one or more filters therein and a drain and clean water outlet near its bottom for egress of clean water from said WAFU.

A portable pool filter cleaning assembly is configured to retain a pool filter on support rod and allow the pool filter to spin from a spray of water. The spinning filter releases debris from the filter surface through centrifugal force. The assembly has drainage features to ensure proper drainage of water collected within the interior of the pool filter and enable proper spinning from the spray of water. The assembly utilizes a support rod with a bottom filter retainer that is conical in shape for engaging with the pool filter aperture. The bottom filter retainer may further have a bearing that enables the pool filter to rotate freely about the rod with very little force. The assembly may include a stand for securing the support rod on a hard surface, such as concrete or on an uneven lawn surface.

A water intake and pretreatment system (10) comprising an inlet for delivering water from a natural source to a reservoir (12); said inlet to reservoir having a net screen (16) to prevent entry of organisms above a predetermined size and including a one-way gate (30) to allow organisms to exit the reservoir; said reservoir further comprising a granular filter media for water and algae filtration; and a drainage layer for removal of filtered water from the granular filter media to a drainage outlet. A local backwashing apparatus (40) is included for localized backwashing of the granular 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.

A water intake and pretreatment system (10) comprising an inlet for delivering water from a natural source to a reservoir (12); said inlet to reservoir having a net screen (16) to prevent entry of organisms above a predetermined size and including a one-way gate (30) to allow organisms to exit the reservoir; said reservoir further comprising a granular filter media for water and algae filtration; and a drainage layer for removal of filtered water from the granular filter media to a drainage outlet. A local backwashing apparatus 40) is included for localized backwashing of the granular filter media.

A support grid assembly for use in a pressure vessel includes one or more screen panel assemblies that are flexibly, fluidly coupled to a central fluid manifold. Each screen panel assembly is operably slidably inserted into a central fluid manifold, whereby a flexible connection fluidly individually seals each screen panel assembly to the central fluid manifold. Through the use of a flexible connection, each screen panel assembly can individually slide, rotate or otherwise shift relative to the central fluid manifold and into engagement with a vessel floor regardless of inconsistencies in the vessel floor.

The present invention relates to a filtering apparatus (1) for the filtration of liquids, in particular water. It comprises, inside a container (11), a first chamber (50) intended to receive liquid to be filtered, a second chamber (54) intended to receive filtered liquid, a first porous wall (51) and a second porous wall (53) which delimit a filtration chamber (40) between them. The first porous wall (51) divides the first chamber (50) from the filtration chamber (40) and the second porous wall (53) divides the second chamber (54) from the filtration chamber (40), so that the filtration chamber (40) is interposed between the first chamber (50) and the second chamber (54). A granular filter material (4) is housed in the filtration chamber (40) and is enclosed between the first porous wall (51) and the second porous wall (53). The first chamber (50) receives the liquid to be filtered at a first height (H1) which is at a higher altitude than the second height (H2) at which the second chamber (54) discharges the filtered liquid. The first chamber (50), the filtration chamber (40) and the second chamber (54) are flanked to each other and, in a section between the first height (H1) and the second height (H2), are all intersected by a plurality of horizontal planes (P) parallel to each other. In use, the liquid to be filtered passes from the first chamber (50) to the second chamber (54) substantially by gravity and through the filtration chamber (40) with a flow path having a horizontal component.

The invention provides methods and systems for sanitizing and/or regenerating porous filter media using dissolved ozone in the filter backwash under fluidized conditions.