Mounds are decentralised wastewater treatment systems whose main purpose is to provide sufficient treatment to the natural environment to produce an effluent equivalent to, or better than, a conventional onsite disposal system. Mounds are pressure-dosed sand filters that discharge directly to natural soil. They lie above the soil surface and are designed to overcome site restrictions such as: slow or fast permeability soils, shallow soil cover over creviced or porous bedrock, or a high water table.
EPA (1999): Decentralized Systems Technology Fact Sheet - Mound Systems. Washington D.C.: United States Environmental Protection Agency (EPA) URL [Accessed: 06.09.2012]