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.

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.

A filter media retainer has a plate having a first end wall, a second end wall, and a pair of longitudinal sidewalls connected to opposing sides of the first end wall and the second end wall. The plate has a top surface opposite a bottom surface. A plurality of hopper-shaped compartments are formed on the top surface and have a first sloped wall and a second sloped wall angled toward the first sloped wall in a direction from the top surface toward the bottom surface. The plate further has a top sidewall on the top surface of the plate separating adjacent hopper-shaped compartments from each other. The plate further has at least one first slot extending through at least one of the first sloped wall and the second sloped wall, and at least one second slot extending through the top sidewall.

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.

The present disclosure relates to a filter apparatus (1) for mechanically filtering a liquid (W). The filter apparatus (1) includes a filter chamber (5) for containing a plurality of filter elements (7) that form a filter pack (29) for filtering the liquid. The filter chamber (5) has a liquid inlet (12) and a liquid outlet (14). The filter apparatus (1) includes means for introducing air into the filter chamber (5) through one or more air inlets (25) to agitate the filter elements (7). The filter chamber (5) is substantially sealed and the air introducing means (22) may be configured to draw air into the filter chamber (5) as liquid is drained from said filter chamber (5). In certain embodiments, the filter chamber (5) may have a substantially constant profile or a substantially continuously tapered profile along its longitudinal axis (X-X). The present disclosure also relates to methods of filtering a liquid (W).

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 local backwashing apparatus 110 for a filtering system comprises an enclosure 119 having an open lower end, positionable above a surface of filter media 92 supported by a drainage layer 96. The enclosure is connected to a mechanical member (300, FIG. 6A) configured to force the enclosure into the filter media and release the force prior to the lower end of the enclosure contacting the drainage layer. The lower end of the enclosure being brought into contact with the drainage layer through a pressure differential between the interior and exterior of the enclosure. A pneumatic system such as an air pump, is in fluid communication with the upper part 127 of the enclosure and is configured to determine an air pressure therein. A pipe system connects the upper part of the enclosure with the pneumatic system and with a discharge structure 132. A control unit is connected to the pneumatic system. Also disclosed is a method of backwashing a filtering system. The backwashing apparatus may be used to pre-treat water.

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 present invention may provide a granular filtration system for filtering effluent water for agricultural operations. The system may comprise a granular media for filtering the effluent water, a vessel for holding the granular media, a filtration inlet, a filtration outlet, a backflush inlet, a backflush outlet, a plurality of filtration members, and a plurality of conduits, the conduits being in fluid communication with the plurality of filtration members, the filtration outlet, and the backflush inlet. The vessel may further comprise a plurality of access ports for accessing the interior of the vessel. The present system provides filtration members with sufficient size, shape, number, and placement to efficiently and evenly backflush the granular media, and a higher quality, hydrodynamically shaped tank which can be backflushed at a lower pressure, reducing water and energy use, leaks, and inconsistencies in the granular media.

A fiber filtering apparatus includes: an enclosure including an upper box and a lower box communicating with the upper box; a strainer installed in the upper box along a longitudinal direction; a plurality of fiber yarn media configured to be fixed to upper and lower fixing means each coupled to upper and lower parts of the strainer; a plurality of fiber ball media configured to be embedded in the lower box to form a second filtering layer; a first pipe configured to be formed on one side wall on the lower part of the upper box and introduced with raw water during filtration and drain backwashing water during backwashing; and a second pipe formed on one side wall on a lower part of the lower box and drain filtered water during the filtration and introduced with washing water during the backwashing.