Performances evaluation of phosphorus removal by apatite in constructed wetlands treating domestic wastewater: Column and pilot experiments

a Cemagref, research unit: Water quality and pollution prevention, 3 bis, quai Chauveau-CP 220, 69336 Lyon Cedex 9France (E-mail: [email protected]; [email protected]; [email protected]) b IRCE Lyon, CNRS-UMR 5256, université Claude Bernard Lyon 1-domaine scientifique de la Doua-VilleurbanneFrance (E-mail: [email protected]) c SINT, 5 rue Boyd, F73 100 AixLesBains, France (E-mail: [email protected]) d Cirsee, Suez Environnement, 38 rue du Président Wilson, 78230 Le Pecq, France (E-mail: [email protected]) Abstract In constructed wetlands (CWs) treating domestic wastewater, good treatment performances are 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 people equivalent (p. e.), 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 have been studied by a very few works. Despite apatite materials appears to possess high and long-term retention capacity, a better knowledge is needed to precise the quality of apatite to be used and the P removal evolution with time and water quality. In this work the P retention kinetics have been studied in two different scales (lab-experiments and pilots) on different apatite qualities. Retention rate in pilots is smaller than the one found in labexperiments and the results suggested that a security coefficient might be applied while designing apatite filter.