A pool filter system includes a filter housing with an open interior. A pleated filter container in the open interior of the filter housing has a pleated filter side wall and divides the interior of the filter housing into an pleated filter compartment and an particulate filter compartment surrounding the pleated filter side wall. The pleated filter side wall has a plurality of pleated filter container openings. A particulate filter medium is within the particulate filter compartment, and a pleated filter is within the open interior of the pleated filter compartment. A water inlet communicates with the particulate filter compartment, and a water outlet communicates with the pleated filter compartment. The pleated filter container openings in the pleated filter container side wall have a dimension that is less than the diameter of the particulate filter medium. A backwash assembly and a method of filtering pool water is also disclosed.

A pool filter system includes a filter housing with an open interior. A pleated filter container in the open interior of the filter housing has a pleated filter side wall and divides the interior of the filter housing into an pleated filter compartment and an particulate filter compartment surrounding the pleated filter side wall. The pleated filter side wall has a plurality of pleated filter container openings. A particulate filter medium is within the particulate filter compartment, and a pleated filter is within the open interior of the pleated filter compartment. A water inlet communicates with the particulate filter compartment, and a water outlet communicates with the pleated filter compartment. The pleated filter container openings in the pleated filter container side wall have a dimension that is less than the diameter of the particulate filter medium. A backwash assembly and a method of filtering pool water is also disclosed.

A saturated layer stormwater filtering system with down-flow layered multimedia filters is disclosed. The filtering system may include an upflow pretreatment chamber and a subsequent filtration chamber. It also includes a snorkel pipe as an adjustable head control or internal baffles. The system incorporates gravity powered partially saturated stormwater media filters to harness the potential energy of stormwater from downspouts and pumped flows from stormwater catchments to drive the polluted stormwater in a hydraulically controlled fashion by gravity through a series of filter media layers.

A saturated layer stormwater filtering system with down-flow layered multimedia filters is disclosed. The filtering system may include an upflow pretreatment chamber and a subsequent filtration chamber. It also includes a snorkel pipe as an adjustable head control or internal baffles. The system incorporates gravity powered partially saturated stormwater media filters to harness the potential energy of stormwater from downspouts and pumped flows from stormwater catchments to drive the polluted stormwater in a hydraulically controlled fashion by gravity through a series of filter media layers.

A filtration media, system and method to passively remove phosphorus and coliforms from wastewater streams is provided. The filtration media system allows wastewater to enter via an inlet toward a diffusor, a filtration media and a filtration media support. The filtered wastewater exits through an outlet. In one aspect, the filtration media broadly comprises sand, activated alumina, peat moss or lime, or any combination thereof. In an exemplary embodiment, the dephosphatation media may further comprise about 20-65% filtration grade sand, about 7-14% granular activated alumina, about 25-50% peat moss and about 5-20% dolomitic lime. The filtration media system may be used in a wastewater treatment method to passively remove phosphorus and coliforms from sewage streams. The dephosphatation media system may be used to passively treat domestic, industrial and commercial sewage streams.

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 first peripheral side may comprise at least one transfer orifice. An intermediate plate member is disposed intermediate the first peripheral side and the second peripheral side along a width dimension. The intermediate plate member may comprise a metering pipe opening. A metering pipe may be sized to be positioned within the metering pipe opening.

The present disclosure provides improved methods for conducting a wash cycle in a filtration unit. The methods may be used alone or in combination with one another to achieve the improvements described herein. Filtration units adapted for carrying out the novel methods are also provided. Through the use of the methods and filtration units described, significant economic benefits are obtained without a significant increase in the costs of the filtration unit or in the costs of operation of the filtration unit.

A filtering device for removing dirt particles and contaminants from a plastic melt is disclosed. The filtering device includes a housing having a filter chamber, an inlet for feeding plastic melt, an outlet for channeling plastic melt out, and a dirt outlet for discharging dirt particles from the housing. The filtering device also includes a filter element arranged in the filter chamber to retain any dirt particles contained in the stream of melt, and a cleaning unit for cleaning the filter element of dirt particles retained by means of the filter element. The cleaning unit having a cleaning head with a scraper member for detaching dirt particles from the filter element. The scraper member is coupled to a servomechanism to press the scraper member onto the surface of the filter element. The servomechanism has at least one bellows cylinder including a foot section, a head section, a deformable bellows element, and a pressure chamber of variable volume.

A filtering device for removing dirt particles and contaminants from a plastic melt is disclosed. The filtering device includes a housing having a filter chamber, an inlet for feeding plastic melt, an outlet for channeling plastic melt out, and a dirt outlet for discharging dirt particles from the housing. The filtering device also includes a filter element arranged in the filter chamber to retain any dirt particles contained in the stream of melt, and a cleaning unit for cleaning the filter element of dirt particles retained by means of the filter element. The cleaning unit having a cleaning head with a scraper member for detaching dirt particles from the filter element. The scraper member is coupled to a servomechanism to press the scraper member onto the surface of the filter element. The servomechanism has at least one bellows cylinder including a foot section, a head section, a deformable bellows element, and a pressure chamber of variable volume.

A filter is provided including a vessel having an input positioned near the top of the vessel for contaminated fluid; the vessel containing media; a drain screen; a propeller rotatable on a drive shaft extending downwardly from the top of the vessel; a deflector plate below the drain screen to impel media outwardly from the center of the vessel; a plurality of baffles positioned on side walls of the vessel; and a drain to remove fluid from the vessel.