Dispersal Option: Shallow Narrow Drainfield
|Shallow narrow pressure-dosed drainfields are
used to disperse wastewater from innovative systems to the
soil environment, and are generally used for wastewater that
has been treated to meet a minimum of 30 mg/L of BOD5 and TSS.
The drainfield lines are placed in the upper soil layers in
order to achieve maximum wastewater treatment through processes
occurring in the soil environment. This shallow placement also
maximizes the vertical separation distance from the bottom
of the drainfield to the groundwater table, providing greater
protection of water resources.
growing above the shallow narrow drainfield lines is generally
very lush, as seen in the photographs above.
The grass is using the moisture and nutrients that are being
dispersed through the drainfield lines, and so removing nitrogen
and phosphorus from the effluent. The roots of the grass also
help to keep the soil aerated.
more information on shallow narrow drainfields:
drainfield option has been studied in great detail, with
the above-referenced results summarizing
of the data obtained. See the report by S. Holden and M. Stolt
for full details of the study, available here.