title: pH and Eh effects on phosphorus fate in constructed wetland's sludge surface deposit.
abstract: The objective of the present study was to assess the influence of extreme pH and redox potential (Eh) conditions on phosphorus (P) retention within the surface sludge deposit layer of a vertical flow constructed wetland (VFCW) where phosphorus was captured by FeCl3 injection. Series of 27 successive batch leaching tests were conducted under acidic, alkaline or reductive conditions using a representative sludge sample taken from an 8-year old VFCW plant. Experiments were followed by monitoring the pH and Eh variations and analysing the releases of P and other selected elements into the solutions. The sludge material was also analyzed before and after leaching, using solution (31)P NMR spectroscopy and sequential chemical extractions, in order to evaluate dissolutions of both organic and inorganic P-bearing species and their respective contributions to P release. The correlations between the monitored variables were analyzed and visualized through principal components analyses (PCA). Results showed a very good stability of P retention in the sludge deposit and a relatively good acid-buffering capacity of the sludge, revealing that the risk of accidental P release into the environment would be extremely low during the real plant operation.
authors: Univ Lyon, INSA Lyon, DEEP, 20 av. A. Einstein, 69621 Villeurbanne Cedex, France; SCIRPE, Society of Design and Production Engineering for Wastewater Purification, 5 Allée Alban Vistel, 69110 Sainte-Foy-Lès-Lyon, France. Electronic address: boram.kim@insa-lyon.fr.
authors: Boram
authors: B
authors: Kim
authors: Univ Lyon, INSA Lyon, DEEP, 20 av. A. Einstein, 69621 Villeurbanne Cedex, France. Electronic address: mathieu.gautier@insa-lyon.fr.
authors: Mathieu
authors: M
authors: Gautier
authors: Univ Lyon, INSA Lyon, DEEP, 20 av. A. Einstein, 69621 Villeurbanne Cedex, France.
authors: Arnaud
authors: A
authors: Simidoff
authors: Univ Lyon, ISA, Institut des Sciences Analytiques, 5 rue de la Doua, 69100 Villeurbanne Cedex, France.
authors: Corinne
authors: C
authors: Sanglar
authors: Univ Lyon, INSA Lyon, DEEP, 20 av. A. Einstein, 69621 Villeurbanne Cedex, France.
authors: Vincent
authors: V
authors: Chatain
authors: SCIRPE, Society of Design and Production Engineering for Wastewater Purification, 5 Allée Alban Vistel, 69110 Sainte-Foy-Lès-Lyon, France.
authors: Philippe
authors: P
authors: Michel
authors: Univ Lyon, INSA Lyon, DEEP, 20 av. A. Einstein, 69621 Villeurbanne Cedex, France.
authors: Rémy
authors: R
authors: Gourdon
mesh_terms: D002712:Chlorides; D005290:Ferric Compounds; D005602:France; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D010758:Phosphorus / Q000032:analysis*; D012722:Sewage / Q000737:chemistry*; D014865:Waste Disposal, Fluid / Q000379:methods*; D053833:Wetlands
chemical_list: D002712:Chlorides; D005290:Ferric Compounds; D012722:Sewage; D010758:Phosphorus; C024555:ferric chloride
keywords: Environmental engineering; Phosphorus leaching; Redox; Surface deposit; Vertical flow constructed wetland; pH