Lagooning (where water forms a surface flow)
The lagoon system set up for the phytostation is composed of two tight basins arranged in series and which communicate. The basins are filled with sewage and are free in the wind. The bottom of the basins is filled with substrate (sand + gravel) on which aquatic plants (Eichhornia crassipes, Pistia stratiotes, Centella asiatica) develop.
Aerobic bacteria grow in "free cultures". Near-surface filtration is aerobic, while deeper water and substrate generally work anaerobically. The first basin allows the reduction of the polluting carbon load and the second allows the reduction of nitrogen and phosphorus and refines the treatment.
This lagoon is an ideal shelter for some animal species such as amphibians ...