Wisconsin sand mound on an WaterNSW property in Burrawang.
Components of a Wisconsin sand mound system.
Sand mounds are used to dispose of effluent on land that is unsuitable for conventional septic tank soil absorption systems due to shallowness, high water table, low permeability or prior disturbance.
The sand mound system includes a septic tank, a dosing chamber, and a mound made of sand fill above the soil surface. Septic tank effluent is distributed in even and timed doses into the mound through a dosing chamber or pump well. Effluent is treated as it moves through the sand mound, then further treated and disposed of in the soil underneath the mound.
Common problems with sand mounds are:
- installing mounds on too steeply sloping sites or deep enough to connect with groundwater
- building the mound too flat, so that rainfall doesn't run off but is absorbed in the mound
- inadequate stormwater diversion drains, causing the mound to become saturated
- mound too small for amount of effluent (hydraulic load).