The purpose of sanitation is to transform water polluted by human activity (domestic, agricultural, industrial) into water that can be assimilated by the natural environment. There are many sanitation solutions on a collective scale such as individual solutions so-called autonomous. All rely on bacteriological activity to clean up contaminated water. Likewise, each system, at the outlet, returns the water to the natural environment by infiltration or sewage farm. At the sanitation outlet, the water is not drinkable. It is very rich in minerals that can be assimilated by the soil and plants, similar to a fertilizer. Returning it to the aquatic environment is prohibited except in the event of impossibility of manure spreading or infiltration. The aquatic environment is more sensitive than the soil, the intake of nutrient-laden water carries a high risk of disturbing the natural environment, going as far as its asphyxiation or eutrophication.