Influence of the water saturation level on phosphorus retention and treatment performances of vertical flow constructed wetland combined with trickling filter and FeCl3 injection
Influence du niveau de saturation sur la rétention du phosphore et performances d'un filtre à écoulement vertical couplé avec un lit bactérien et injection de FeCl3
Kim, B. ; Gautier, M. ; Molle, P. ; Michel, P. ; Gourdon, R.
Type de document
Article de revue scientifique à comité de lecture
Affiliation de l'auteur
UNIVERSITE DE LYON INSA LGCIE LABORATOIRE DE GENIE CIVIL ET INGENIERIE ENVIRONNEMENTALE VILLEURBANNE FRA ; UNIVERSITE DE LYON INSA LGCIE LABORATOIRE DE GENIE CIVIL ET INGENIERIE ENVIRONNEMENTALE VILLEURBANNE FRA ; IRSTEA LYON UR MALY FRA ; SCIRPE SAINTE FOY LES LYON FRA ; UNIVERSITE DE LYON INSA LGCIE LABORATOIRE DE GENIE CIVIL ET INGENIERIE ENVIRONNEMENTALE VILLEURBANNE FRA
Résumé / Abstract
The aim of the study was to determine the effects on treatment efficiency of oxidation-reduction (redox) conditions that are caused by different water saturation levels within vertical-flow constructed wetlands (VFCW), with specific attention to phosphorus (P) retention. The study was conducted by monitoring over 18 weeks a pilot-scale system consisting of a biological aerobic trickling filter as a biological pre-treatment step, followed by ferric chloride (FeCl3) addition for phosphate removal and a stage of VFCW. By adjusting the water saturation level, the VFCW was operated successively under fully unsaturated, partly saturated, completely saturated (flooded), and then again unsaturated conditions. Redox potentials (Eh) were measured at three different levels within the VFCW. Results revealed that Eh was logically affected by the water-saturation level and the feeding-resting periods. Treatment efficiency was very good under fully unsaturated and partly saturated conditions. Under flooded conditions, the performance of the filter declined when the flood was maintained for around one week. However, VFCW regained its previous efficiency after the effluent was drained out and aerobic conditions were restored, indicating that the system was resistant and robust enough that periodical flooding did not affect its performance afterwards.
Ecological Engineering, vol. 80, p. 53 - 61