Effet des macrophytes aquatiques sur le traitement d’eau contaminée à l’ACC et au PCP

L’objectif principal de ce projet est d’évaluer le potentiel d’un système de marais filtrants combinés pour le traitement d’un lixiviat contaminé aux agents de préservations du bois - l’arséniate de cuivre chromaté (ACC) et le pentachlorophénol (PCP) - en portant une attention particulière au rôle des plantes. Pour ce faire, une expérience en pot faisant varier la concentration d’exposition de quatre espèces de macrophyte (Typha angustifolia, Phalaris arundinacea, Phragmites australis americanus et Phragmites australis australis) a été effectuée. Le suivi de quatre marais filtrants à écoulement horizontal sous-surfacique, plantés d’une des quatre espèces de macrophyte et d’un bassin planté de saules (Salix Miyabeana SX67) a également été réalisé. La résistance des plantes au milieu contaminé, la capacité de bioaccumulation des macrophytes et les efficacités de traitement des différents systèmes ont été analysés. Nos résultats montrent que la concentration d’exposition n’influence pas la capacité des plantes à croître en milieu contaminé. Par contre, il existe une relation dose-réponse entre la concentration d’exposition et la capacité de bioaccumulation des macrophytes. Les quatre marais pilotes ont tous des efficacités de traitements supérieures à 55% en 2013 et 82% en 2014 pour les contaminants à l’étude. Le bassin de saule a la capacité théorique d’évapotranspirer jusqu’à 1200 L par jour. De plus, ses efficacités de traitements sont supérieures à 59% pour tous les composés à l’étude. L’utilisation de marais filtrants pour le traitement d’un lixiviat contaminé aux agents de préservations du bois est donc une alternative intéressante aux méthodes de traitement conventionnel.The main objective of this project is to evaluate the capacity of a combined constructed wetland system to treat a leachate polluted with two wood preservatives-chromium copper arsenate (CCA) and pentachlorophenol (PCP)- according a particular importance to the role of plants. The effect of the exposure concentration on four macrophytes species (Typha angustifolia, Phalaris arundinacea, Phragmites australis americanus and Phragmites australis australis) was evaluated using a pot experiment. Four HSSF pilot constructed wetlands, planted with one of these plants species, were monitored. The role of an HSSF constructed wetland, planted with willow (Salix Miyabeana SX67), placed at the end of the treatment chain was also assessed. The plants growth and survival and their bioaccumulation capacity were measured, and the system treatment efficiencies were monitored. There was no effect of the concentration on plants growth but the higher exposure concentration resulted in a higher bioaccumulation in the roots of the four macrophytes. All four pilots CW showed treatment efficiencies superior to 55% in 2013 and to 82% in 2014 for the pollutants tested. The willows CW have the theorical capacity to evapotranspirate up to 1200 L of water. Its treatments efficiencies were over 59% for all the pollutants tested. A combined constructed wetland system is a good alternative to conventional methods to treat a leachate polluted with wood preservatives

Treatment of a mixed wood preservative leachate by a hybrid constructed wetland and a willow planted filter

The performance and removal mechanisms of a hybrid constructed wetland (HCW) followed by a willow planted filter (WPF) were evaluated for the treatment of a leachate contaminated by wood pole preservatives (pentachlorophenol (PCP) and chromated copper arsenate) to reach the storm sewer discharge limits. The HCW aimed to dechlorinate the PCP and polychlorodibenzo-p-dioxins/polychlorodibenzofuran (PCDD/F) and to remove metals by adsorption and precipitation. The HCW was efficient in removing PCP (>98.6%), oil, arsenic (99.4%), chromium (>99.2%), copper (>99.6%%) and iron (29%) to under their discharge limits, but it was unable to reach those of Mn and PCDD/F, with residual concentrations of 0.11 mg Mn/L and 0.32 pg TEQ/L. Iron and manganese could be removed but were subsequently released by the HCW due to low redox conditions. No dechlorination of PCDD/F was observed since its chlorination profile remained the same in the different sections of the HCW. Adsorption was the most probable removal mechanism of PCDD/F. The WPF was able to remove some residual contamination, but it released Mn at a gradually decreasing rate. Total evapotranspiration of the leachate by a larger fertilized WPF and the construction of an underground retention basin are proposed to prevent any discharge of PCDD/F traces in the environment

Macrophyte Potential to Treat Leachate Contaminated with Wood Preservatives: Plant Tolerance and Bioaccumulation Capacity

Pentachlorophenol and chromated copper arsenate (CCA) have been used worldwide as wood preservatives, but these compounds can toxify ecosystems when they leach into the soil and water. This study aimed to evaluate the capacity of four treatment wetland macrophytes, Phalaris arundinacea, Typha angustifolia, and two subspecies of Phragmites australis, to tolerate and treat leachates containing wood preservatives. The experiment was conducted using 96 plant pots in 12 tanks filled with three leachate concentrations compared to uncontaminated water. Biomass production and bioaccumulation were measured after 35 and 70 days of exposure. There were no significant effects of leachate contamination concentration on plant biomass for any species. No contaminants were detected in aboveground parts of the macrophytes, precluding their use for phytoextraction within the tested contamination levels. However, all species accumulated As and chlorinated phenols in belowground parts, and this accumulation was more prevalent under a more concentrated leachate. Up to 0.5 mg pentachlorophenol/kg (from 81 µg/L in the leachate) and 50 mg As/kg (from 330 µg/L in the leachate) were accumulated in the belowground biomass. Given their high productivity and tolerance to the contaminants, the tested macrophytes showed phytostabilization potential and could enhance the degradation of phenols from leachates contaminated with wood preservatives in treatment wetlands

Macrophyte potential to treat leachate contaminated with wood preservatives: plant tolerance and bioaccumulation capacity

Pentachlorophenol and chromated copper arsenate (CCA) have been used worldwide as wood preservatives, but these compounds can toxify ecosystems when they leach into the soil and water. This study aimed to evaluate the capacity of four treatment wetland macrophytes, Phalaris arundinacea, Typha angustifolia, and two subspecies of Phragmites australis, to tolerate and treat leachates containing wood preservatives. The experiment was conducted using 96 plant pots in 12 tanks filled with three leachate concentrations compared to uncontaminated water. Biomass production and bioaccumulation were measured after 35 and 70 days of exposure. There were no significant effects of leachate contamination concentration on plant biomass for any species. No contaminants were detected in aboveground parts of the macrophytes, precluding their use for phytoextraction within the tested contamination levels. However, all species accumulated As and chlorinated phenols in belowground parts, and this accumulation was more prevalent under a more concentrated leachate. Up to 0.5 mg pentachlorophenol/kg (from 81 mu g/L in the leachate) and 50 mg As/kg (from 330 mu g/L in the leachate) were accumulated in the belowground biomass. Given their high productivity and tolerance to the contaminants, the tested macrophytes showed phytostabilization potential and could enhance the degradation of phenols from leachates contaminated with wood preservatives in treatment wetlands

Les commensaux : Quand l'art se fait circonstances = Les commensaux : When Art Becomes Circumstance

Published to document Skol’s 2000-2001 season dedicated to new forms of “relational” practices, this anthology doubles as a catalogue featuring comments and meditations on that theme, present in the proceedings of a seminar entitled “Des formes de l’art aux formes de vie.” More than 35 contributions by artists and theoreticians are grouped under the following four headings: infiltration (investing the public space), circulation (using the object), encounters (questioning being together) and resistance (redefining “being an artist”). Index. Texts in French and English. Biographical notes. 120 bibl. ref

Frontières, marges et confins

Cet ouvrage met en question les termes de frontières, de marges et de confins dans une perspective pluridisciplinaire. Il aborde respectivement, l’éthique des frontières, l’espace psychique, l’altérité et les marges telles qu’elles sont vécues et perçues dans les champs de la sociologie, de l’histoire, de l’histoire de l’art et des arts du spectacle. Il interroge également les marginalités créatrices de l’écriture et la représentation des marges en littérature. Témoin de la volonté d’un groupe de chercheurs en sciences humaines de sortir des champs de leur discipline pour esquisser un espace transfrontalier, il inaugure la collection « Chemins croisés ». En faisant émerger de nouveaux objets d’investigation, de nouveaux paradigmes dans une zone frontalière où s’épanouissent les échanges, ces chercheurs souhaitent, tels les drogmans d’antan, servir d’interface en incarnant la fécondité des espaces d’entre-deux dans lesquels s’enrichissent les langues et les cultures. Penser la frontière, les marges et les confins, c’est convoquer la figure de l’étranger, esquisser celle du passeur, dévoiler l’in-su que chacun porte en soi et instaurer des passerelles entre générations et civilisations ; c’est affirmer, pour reprendre les termes de Montaigne, que nous « pensons toujours ailleurs »