The species chosen in the phytostation are: Pistia stratiotes, Eichhornia crassipes, Ipomea aquatic, Typha latifolia and Phragmites mauritianus…

Role of plants in purification :
Aquatic vegetation composed of vascular macrophyte plants (higher plants) and non-vascular plants (algae) play an important role in the purification of wastewater.
Algae through the phenomenon of photosynthesis increase the oxygen content of water which in turn affects nutrients and reactions.
Vascular plants contribute to the treatment of wastewater by a number of means:
- they stabilize substrates and limit the speed of water flow, which allows the suspended material, carbon, nutrients and trace elements to integrate plant tissues ;
- they ventilate the substrate by bringing air between their stem and the roots, these are points of fixation for the micro-organisms ;
- they produce humus at the moment of their decomposition.

Plants in the vegetated filters:
- improve the role of filter, limit clogging, formation of preferential surface flow and the effect of erosion ;
- Also increase the retention time of the effluent and therefore its degradation by soil organisms.
- promote the development and activity of the microorganisms responsible for the purification and ;
- absorb nutrients (nitrogen, phosphorus ...).