Waste water treatment system

DETAILED DESCRIPTION The present invention has solved the problems cited above, and is a biological waste treatment assembly for use between a septic tank and drain field.
Broadly, this comprises an upper bed portion for aerobic biological treatment of an effluent from the septic tank, a lower sump portion for holding the effluent in a reservoir, this having a lower, relatively oxygen-free layer, and pump means for delivering a flow of the effluent to an upper portion of the bed so that the effluent migrates through the bed portion and undergoes aerobic biological treatment therein.
Means are provided for collecting the effluent which has migrated through the aerobic bed portion of the assembly, and for draining this from the bed portion directly to the oxygen-free lower layer of the reservoir so that the effluent undergoes anaerobic biological treatment therein.
Preferably, the means for collecting the effluent may comprise a drain pan which is mounted beneath the upper bed portion of the assembly so as to receive the effluent which has migrated downwardly therethrough, and the means for draining the effluent to the oxygen-free lower layer of the reservoir may comprise a drain conduit having an upper end in fluid communication with this drain pan and a lower end in fluid communication with the lower, oxygen-free layer of the reservoir.
Means are also preferably provided for discharging the effluent from the reservoir after this has undergone at least one cycle through aerobic treatment in the upper bed portion of the assembly and anaerobic treatment in the reservoir of the assembly.
The assembly may further comprise means for aerating the flow of effluent from the pump means prior to this flow entering the aerobic upper bed portion of the assembly.
The means for delivering the flow of effluent to the bed may comprise a pump for drawing the effluent from the reservoir in the sump and a conduit for conveying the flow from the pump to the upper portion of the bed, and in this case, the means for aerating the flow of effluent may preferably comprise means for injecting air into the conduit so as to aerate the effluent therein