Lagooning is a natural technique for used water treatment that uses the self-purifying functions of aquatic ecosystems.
Principle of lagooning
The principle is to pass sewage by gravity flow through a succession of ponds where the metabolism of organisms (bacteria, plants, etc.) ensures the depollution of the water (phytoremediation) while the substrate and plants filter the material.
Advantages of lagooning
Lagooning is an interesting option due to its low energy and economic cost, as well as its insertion into landscapes and local biodiversity as a wetland.
Disadvantages of lagooning
However, this technique requires large land surfaces and does not adapt well to major seasonal variations (for example, in touristic sites) as well as occasional, major pollution. Moreover, this system does not produce water that is 100% free from pollutants.
Operating diagram of a lagooning pond. © F. Lamiot, Wikimedia CC by-sa 3.0