Abstract
In constructed wetlands (CWs) treating domestic wastewater, good treatment performance is obtained on mains parameters except phosphorus (P) which can cause eutrophication problems. In order to improve P removal from wastewater with a low specific filter surface per person equivalent (pe), different materials have been tested: man-made and natural materials, industrial by-products, and a mixture of these materials. The P removal by natural apatite has been studied by only a limited amount of work. Apatite materials appear to possess high and long-term removal capacity, thus a better knowledge is needed to determine the quality of apatite to be used and the P removal evolution with time and water quality. In this work the P removal rates were studied in two different scales (lab-experiments and pilot units) on different apatite qualities. Removal rate in the pilot units was smaller than the one found in lab-scale columns and the results suggested that a security coefficient might be applied while designing the apatite filter.
Acknowledgements
The authors would like to thank the Rhône-Alpes Chemicals and Environment competitiveness cluster ‘Axelera’ in which this project took place. We thank OCP (Morocco) and FERPHOS (Algeria) groups for providing the apatite materials used in this study.