These systems require a pump or dosing siphon, and require pretreatment by a tank for solids removal. The systems take advantage of both evaporation and infiltration, and an advantage is that they dispose of water. One problem with Wisconsin mounds is that water can leak out of the toe. Wisconsin mounds should be inspected annually. Evaporation beds are sometimes used in Arizona, and they consist of a shallow excavated area that is filled with sand.
Water is ponded to a depth just below the sand surface.
These systems require a septic tank for solids removal. They are expensive and it is difficult to find sand fill material. The pits must be lined, and they are often ugly. Constructed wetlands may include subsurface flow system wetlands, free water surface wetlands or floating aquatic plant systems. Wetlands require pretreatment by a septic tanks for solids removal.