3. Conclusion and outlook

Among the various solutions for retaining phosphorus in extensive systems, plants are not the most economical in terms of surface area. Soil, whether natural or artificial, is a major factor in the efficiency of phosphorus retention, if we want to avoid surface or groundwater discharge. Setting up a physico-chemical dephosphatation system, in addition to complicating the process, does not seem realistic with FeCl ₃ in view of the experiments carried out, and the use of aluminum salts has not yet been validated experimentally.

Using a specific material to improve the soil's ability to retain phosphorus is the solution favoured by the scientific community, and the research carried out at Cemagref in Lyon over the last few years on apatite is proving promising. The use of minerals based on natural calcium phosphates favors...