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: 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.