Abstract: Filter vaults are shown and disclosed. In some embodiments, the filter vault includes an at least partially impervious and at least partially submersible filter housing. The housing includes an inlet opening that permits unfiltered wastewater having suspended solids to enter the housing. The filter vault further includes a filter assembly. The filter assembly includes one or more filter elements positioned within the housing. Each of the filter elements includes an upper end and a lower end. Each of the filter elements includes a filtering surface that is exposed to the unfiltered wastewater. The inlet opening allows accumulated solids from said filtering surface to exit said housing.

Abstract: A method and apparatus for passive self-cleaning filtration of a liquid containing suspended solids is disclosed. A filter assembly of upright cylindrical filter tubes having open, downwardly-facing ends is placed within a tank of unfiltered liquid. The filter assembly is positioned in the flow of liquid through the tank such that the unfiltered liquid must pass through the filter tubes prior to discharge from the tank. The inner walls of the filter tubes are smooth with small filtering holes. Unfiltered liquid is passes up into the filter tubes and the solids are collected in the tubes and on the smooth walls. Filtered liquid that has passed through the filter tubes is kept separated from the unfiltered liquid by a barrier that functionally prevents passage of unfiltered liquid. The filtered liquid is passed out of the tank. A filter housing protects the filtered liquid and the outside surface of the filter tubes from unfiltered liquid.

Abstract: A wastewater treatment system comprises a septic tank which flows liquid effluent through an aerobic filter. The aerobic filter has a textile filter media. In one aspect, the textile filter media has relatively high open area and relatively low or moderate water holding capacity. In another aspect, the filter media comprises a plurality of vertically oriented textile sheets having a relatively small gap between adjacent sheets.

Abstract: A wastewater treatment system comprises a septic tank which flows substantially all of its liquid effluent through an aerobic filter having a filter medium to produce a nitrified filtrate of reduced biological oxygen demand (BOD) and total suspended solids (TSS). The majority of the filtrate is returned to the septic tank for denitrification followed by further recirculation through the aerobic filter. All permanent discharge of effluent from the system is in the form of filtrate from an aerobic filter. Permanent discharge of effluent directly from the septic tank is prevented.

Abstract: A method of improving the quality of septic tank effluent is disclosed. Sewage wastewater having a significant concentration of waste solids is flowed to a septic tank. In the septic tank the solids are allowed to separate from the wastewater to form a relatively clear horizontal liquid layer between sludge and scum layers. At least a portion of the liquid layer is flowed from a recirculation outlet through an aerobic filter to produce a filter effluent. The filter effluent is flowed to the septic tank. A septic tank effluent is discharged from a septic tank discharge outlet which is spaced apart from the inlet and which is in fluid communication with the liquid. The septic tank effluent has reduced levels of total nitrogen, BOD and total suspended solids.

Abstract: A method of filtering solids from the effluent from a wastewater collection container such as a septic tank is disclosed. A mesh screen filter is immersed in wastewater having a concentration of waste solids which have been allowed to distribute into a scum layer and a sludge layer with a horizontal layer of liquid therebetween. The filter is surrounded with a housing, and the interior surface of the housing is exposed to the horizontal layer of liquid through a plurality of apertures in the housing. Liquid from the horizontal layer flows through the apertures into the housing and thereafter the liquid flows from one side of the filter to an opposite side thereof through a mesh screen filtering surface area greater than the interior surface area of the housing. Thereafter, the liquid flows through a liquid effluent outlet of the container. This filter is very efficient and consequently provides a high quality effluent, while resisting clogging and resultant collapse of the mesh screen surface area.

Abstract: An improved method and apparatus for treating wastewater in a recirculating filter is disclosed. Solids are removed from the wastewater by gravitational separation and the wastewater is flowed to a tank. At least a portion of the wastewater is flowed from the tank to a filter comprised of filter media and flowed through the media to produce a filtrate. The amount of wastewater in the tank is sensed. When the amount of wastewater sensed is at least a predetermined amount, a fraction, less than all but more than none, of the filtrate is returned to the tank. When the amount of wastewater is less than the predetermined amount, more than the fraction of filtrate is returned to the tank by decreasing resistance to flow of the filtrate to the tank. The apparatus includes a tank and a filter interconnected by a conduit for conducting liquid from the tank to the filter. A conduit assembly interconnects a filter outlet and a discharge conduit for conducting liquid from the filter to the discharge conduit.

Abstract: An on-site wastewater treatment system distributes septic tank effluent over a particulate media filter bed through a distribution manifold at a sufficient volumetric flow rate relative to the cross-sectional area of the distribution conduits to inhibit undesirable biological growth in the conduits and in the filter by creating a scouring effect in the conduits. This effect prevents clogging of the conduits and maximizes the even distribution of effluent in the filter. A mesh fabric intercepts the downward flow of the effluent in the filter to further aid in the even distribution of effluent in the filter. Orifice shields also aid in such distribution by preventing clogging of orifices embedded in the filter media. A high pressure switch in the distribution manifold and a high water alarm in the filter pump basin indicate when required maintenance is necessary, and the switch controlling the high water alarm temporarily disables the septic tank pump as well.

Abstract: A method for filtering and discharging waste water from a septic tank in predetermined increments and preventing passage of suspended solids from the tank while resisting blockage of the fluid discharge apparatus by such solids. A removable fluid discharge device, such as a submersible pump or dosing siphon with a trigger trap, is enclosed within an encircling filter element which is similarly encircled by a protective housing, and the entire assembly is located within a septic tank immersed in waste water. The protective housing is impervious to the passage of waste water into its interior except through apertures located in the vertical sidewalls so situated as to allow water from only the clearest layer within the tank to enter into the housing and contact the filter. Functionally, the housing protects the filter from blockage by the high concentration of solids present in the layers above and below the clearest layer.