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 multi-layer media bed filter with an increasing density of media from the finest media on the top to the coarsest media on the bottom is backwashed using air without significantly disrupting stratification of the media layers. When the air is stopped, the contaminants in the liquid above the finest media that were removed by the airflow are flushed away either with liquid injected above the media or by a liquid flow through the media that does not remove the finest media. The amount of contaminants that remain in the finest media with the stratification-maintaining air backwash is significantly less than when using liquid backwash alone, whether the liquid backwash uses a flow rate sufficient to suspend the micromedia or below a suspending flow rate.

A multi-layer media bed filter with an increasing density of media from the finest media on the top to the coarsest media on the bottom is backwashed using air without significantly disrupting stratification of the media layers. When the air is stopped, the contaminants in the liquid above the finest media that were removed by the airflow are flushed away either with liquid injected above the media or by a liquid flow through the media that does not remove the finest media. The amount of contaminants that remain in the finest media with the stratification-maintaining air backwash is significantly less than when using liquid backwash alone, whether the liquid backwash uses a flow rate sufficient to suspend the micromedia or below a suspending flow rate.

Methods and apparatus for liquid/solid separation for use in applications such as dewatering fine particulate solids, and recovery of valuable metals from ore in a leaching process are provided. One application relates to methods of agitation leaching of metals such as gold from gold-bearing feedstock. A slurry is formed in a tank by agitation, and allowed to settle. A filter bed forms to drain the liquid from the tank, and a vertical screen pipe such as a well point addresses the formation of an impervious film on the upper surface of the filter bed.

Methods and apparatus for liquid/solid separation for use in applications such as dewatering fine particulate solids, and recovery of valuable metals from ore in a leaching process are provided. One application relates to methods of agitation leaching of metals such as gold from gold-bearing feedstock. A slurry is formed in a tank by agitation, and allowed to settle. A filter bed forms to drain the liquid from the tank, and a vertical screen pipe such as a well point addresses the formation of an impervious film on the upper surface of the filter bed.

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 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.

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.

A filtration apparatus includes a filtration tank; a layer of filtration media that filters supplied raw water by passing the raw water therethrough within the interior of the filtration tank; and a screw cleansing mechanism having a cylindrical outer cylinder which is provided within the filtration tank in a vertical orientation, a spiral shaped screw which is provided such that the long axis thereof extends in the longitudinal direction of the outer cylinder, and a screw driving member for rotating the screw, that scrubs and cleans filtration media by rotating the screw. The screw is in the shape of a coil spring.