Then construction fabric and additional soil are placed on top of the gravel to help keep the pipes from freezing. The distribution pipes that are fed by the dosing chamber are placed on top of the sand in gravel.

A 24-inch layer of specifically sized sand is placed on top of the soil. Standards created by Ohio State University state that 24 inches of soil should be above the limiting layer in the soil. The layer depths are determined by the depth of the limiting layer of the soil, which may be a seasonal water table, bedrock, fragrant, or glacial till. The mound system does not allow all the effluent to enter the mound at once, accordingly allowing it to clean the effluent more effectively and helping keep the system from failing. Final treatment and disposal occur in the soil beneath the mound. Wastewater is partially treated as it moves through the mound sand. Effluents are sent to a second tank called a dosing chamber, from which they are distributed to the mound at a metered rate (in doses). Wastes from homes are sent to the septic tank where the solid portion sinks to the bottom of the tank. The mound system includes a septic tank, a dosing chamber, and a mound.

Some soils are too high in permeability, allowing water to quickly pass through it, hindering purification effectiveness and allowing contamination to spread to nearby water sources or ecosystems.Īreas of low soil permeability, such as areas with high water tables and limited soil cover over porous bedrock, can result in contaminated surface pooling. Mound systems are used to help purify and transport water efficiently. This project published the first ever design manual for identifying the appropriate site conditions and design criteria for mounds. In 1976, the University of Wisconsin studied the design of mound systems as part of the university's Waste Management Project. and was known as the Nodak Disposal System. The mound system was designed in the 1930s by the North Dakota College of Agriculture.

Sand of time mount