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Compact unsaturated/saturated vertical flow constructed wetland system under tropical conditions: Nitrogen removal and footprint reduction | Filtre planté non saturé/saturé compact en milieu tropical : traitement de l'azote et emprise foncière 全文
2016
Lombard Latune, R. | Mangeot, L. | Pelus, L. | L'Etang, F. | Fina, N | Leguennec, B. | Molle, Pascal
The French Overseas Territories experience big sanitations problems and have to comply with both French and EU regulations. Vertical flow constructed wetland (VFCW) appear well adapted to the context of these regions, but their adaptation to tropical climate requires new guidelines to be defined (area needed, number of filters, species of plants, material to be used …). To this end ATTENTIVE project was build up in the French Antilles with local water offices and supported by the national water authorities. Three different VFCW fed with raw wastewater were built in Martinique and Guadeloupe and are now under monitoring. While the 3 plants are actually in operation, this paper will focus on Taupinière plant (Martinique), sized for 900 p.e., in operation since October 2014. The treatment plant is composed of aunsaturated/saturated vertical flow constructed wetland, receiving raw domestic wastewaters, followed by a simplified trickling filter.The first stage is 0,8m²/p.e. with two filters in parallel (360 m² each), with a 40 cm unsaturated first layer of 2/4 mm gravel, a 15 cm transition layer of 11/22 with intermediate passive aeration pipes and a 60 cm saturated layer at the bottom made of 20/40 pea gravel. The trickling filter(116 m²)is composed of 150 cm of pumice stones. The sludge accumulated at the bottom of the trickling filter is sent back to the first stage.A recirculation loop is implemented on the trickling filter. Before the outlet, effluent passes through UV. The regulationobjectives is to achieve 90% removal for COD, BOD5 and TSS, 80% for TKN, and less than 1000 unit per 100 mL for E.coli and intestinal streptococcus. Nevertheless, the monitoring look after optimal operation to increase TN removal rates as well as the maximum loads that can be treated. The monitoring consists on classical daily composite samples at each treatment stages (30 campaigns) as well as online measurements. The later aim at measuring flows, climatic conditions, and COD, BOD5, and Nitrate (UV/visible analysis) at each treatment stages. Three different loading phases has been implemented from 30 % of the nominal load to 150 %. The paper will present performances of this compact (less than 1 m²/p.e.) treatment system in both dry and rainy season and discuss the optimization of TN removal as well as the footprint reduction with the high loads that can be implemented.
显示更多 [+] 显示较少 [-]Annual variation in neustonic micro- and meso-plastic particles and zooplankton in the Bay of Calvi (Mediterranean–Corsica) 全文
2014
Collignon, Amandine | Hecq, Jean-Henri | Galgani, François | Collard, France | Goffart, Anne
peer reviewed | The annual variation in neustonic plastic particles and zooplankton was studied in the Bay of Calvi 23 (Corsica) between 30 August 2011 and 7 August 2012. Plastic particles were classified into three size classes, small microplastics (0.2–2 mm), large microplastics (2–5 mm) and mesoplastics (5–10 mm). 74% of the 38 samples contained plastic particles of varying composition: e.g. filaments, polystyrene, thin plastic films. An average concentration of 6.2 particles/100 m2 was observed. The highest abundance values (69 particles/100 m2) observed occurred during periods of low offshore wind conditions. These values rose in the same order of magnitude as in previous studies in the North Western Mediterranean. The relationships between the abundance values of the size classes between zooplankton and plastic particles were then examined. The ratio for the intermediate size class (2–5 mm) reached 2.73. This would suggest a potential confusion for predators regarding planktonic prey of this size class.
显示更多 [+] 显示较少 [-]Assessing Migration of Uranium through Chalk Substrate: Field Study and Reactive Transport Modelling 全文
2012
Crançon, Pierre | Mangeret, Arnaud | De Windt, Laurent
The migration of uranium from polluted soil has been investigated in the field, and through modelling of thermodynamics and kinetics of uranium-water-rock interactions. Field monitoring following surface contamination by uranium deposits revealed up to 5 m deep uranium migration in soil and chalk substrate, as well as uranium concentrations in groundwater significantly higher than the geochemical background. Such observations can hardly be explained by a pure reactive transport dominated by reversible adsorption of uranium onto mineral phases. Therefore, a reactive transport model using the HYTEC code has been developed to better assess uranium migration through soil to the carbonate aquifer. Reactive transport modelling shows that adsorption of U (VI) at equilibrium on goethite at pH 7 is responsible for strong immobilization of uranium in the soil and carbonate matrix, matching uranium concentration profiles observed in boreholes. Simulations considering highly mobile ternary complex Ca2UO2(CO3)3(aq) in the aqueous phase cannot account alone for the rapid migration of uranium through the unsaturated zone. Without a mobile colloidal phase, the model clearly underestimates the concentration of aqueous U(VI) that reached groundwater underneath polluted soils.
显示更多 [+] 显示较少 [-]Life Cycle environmental Assessment (LCA) of sanitation systems including sewerage: Case of Vertical Flow Constructed Wetlands versus activated sludge 全文
2010
Roux, P. | Boutin, C. | Risch, E. | Heduit, A.
L'article présente l'application de l'Analyse du Cycle de Vie (ACV) à un système d'assainissement complet, incluant le réseau d'égout. Il présente d'abord les hypothèses retenues pour l'ACV concernant les deux systèmes de traitement des eaux usées ayant tous les deux la même charge nominale quotidienne de la DBO 5 et associés au même réseau d'égouts. Ces systèmes correspondent respectivement à (i) un "filtre planté de roseaux à lit vertical (VFCW)" pour lequelle un inventaire détaillé des flux émis et des ressources consommées a été élaboré et (ii) une STEP à « boues activées » boues » issue de la base de données d'ACV Ecoinvent LCI. Les résultats d'ACV soulignent l'importance de l'eutrophisation qui peut facilement s'expliquer par la suppression incomplète de l'azote total et du phosphore total dans un VFCW. De façon plus surprenante, l'impact du réseau semble considérable. Enfin, l'article analyse l'applicabilité et les limites de l'ACV pour les systèmes de traitement des eaux usées. / The article presents the application of Life Cycle Assessment (LCA) to a complete sanitation system including the sewer network. It first describes the LCA hypothesis which concerns two types of waste water-treatment plant with the same daily nominal load in BOD5 and associated to the same sewer network derived from the Life Cycle Inventory (LCI) database Ecoinvent. The two wastewater treatment systems compared are (i) a Vertical Flow Constructed Wetlands (VFCW) for which a detailed inventory was elaborated and (ii) an activated sludge stemming from the LCI database Ecoinvent. LCA scores of VFCW highlight the importance of eutrophication which can be easily explained by the incomplete removal of total N and total P in a VFCW. In a more surprising way, the impact of the network seems considerable. Finally, the article analyses the applicability and limitations of LCA for wastewater treatment with regard to water quality and the needed improvements of water status in LCA.
显示更多 [+] 显示较少 [-]Metal pollution of agricultural soils: risk assessment and management 全文
2010
Pellerin, Sylvain, | Nguyen, Christophe | Laporte, Marie-Aline | Denaix, Laurence
Phosphorus removal by apatite in horizontal flow constructed wetlands: kinetics and treatment reliability 全文
2008
Harouiya, N. | Molle, Pascal | Prost Boucle, S. | Liénard, A.
Phosphorus removal in constructed wetlands have received particular attention last decades by using specific materials promoting adsorption/precipitation mechanisms. Recent studies have shown interest in using apatite materials to promote P precipitation onto the particle surface. As previous trials were mainly done by lab experiments, this present study aims to evaluate the real potential of apatites to remove P from wastewater in pilots and a full-scale plant. Two different apatites have been studied in 1.5 m² pilots fed with wastewater from the outlet of a trickling filter. They were monitored to follow inlet/oulet flows, hydraulic gradient, meteorological conditions, pH, temperature, and redox potential. Treatment performances were evaluated by regular complete analysis (COD, BOD, SS, nitrogen and phosphorus forms, Ca) as well as PO4-P by a WTW online analyser. At the same time a full-scale experiment study have been done to point out P retention properties in real conditions over a 2 years period. P retention kinetics of two qualities of apatites are presented and discussed according to the temperature dependence. In this work apatite appears to have high retention capacity and is still an interesting way for P removal in constructed wetlands. However, other qualities of apatite must be studied for a better reliability of treatment.
显示更多 [+] 显示较少 [-]Comparison of different stomatal conductance algorithms for ozone flux modelling 全文
2007
Buker, P. | Emberson, L.D. | Ashmore, M.R. | Cambridge, H.M. | Jacobs, C.M.J. | Massman, W.J. | Müller, J. | Nikolov, N. | Novak, K. | Oksanen, E. | Schaub, M. | Torre Llorente, Daniel de la
A multiplicative and a semi-mechanistic, BWB-type [Ball, J.T., Woodrow, I.E., Berry, J.A., 1987. A model predicting stomatalconductance and its contribution to the control of photosynthesis under different environmental conditions. In: Biggens, J. (Ed.), Progress in Photosynthesis Research, vol. IV. Martinus Nijhoff, Dordrecht, pp. 221–224.] algorithm for calculating stomatalconductance (gs) at the leaf level have been parameterised for two crop and two tree species to test their use in regional scale ozone deposition modelling. The algorithms were tested against measured, site-specific data for durum wheat, grapevine, beech and birch of different European provenances. A direct comparison of both algorithms showed a similar performance in predicting hourly means and daily time-courses of gs, whereas the multiplicative algorithm outperformed the BWB-type algorithm in modelling seasonal time-courses due to the inclusion of a phenology function. The re-parameterisation of the algorithms for local conditions in order to validate ozone deposition modelling on a European scale reveals the higher input requirements of the BWB-type algorithm as compared to the multiplicative algorithm because of the need of the former to model net photosynthesis (An)
显示更多 [+] 显示较少 [-]Maintaining viable earthworm populations in frequently inundated river flood plains. Does plasticity in maturation in Lumbricus rubellus promote population survival?
2004
Klok, C. | Zorn, M. | Koolhaas, J.E. | Eijsackers, H.J.P. | Gestel, C.A.M. van
Growth response to ozone of annual species from Mediterranean pastures 全文
2004
Gimeno, Benjamín | Bermejo, V. | Sanz, J. | Torre Llorente, Daniel de la | Elvira, S.
Ozone (O3) phytotoxicity has been reported on a wide range of plant species. However, scarce information has been provided regarding the sensitivity of semi-natural grassland species, especially those from dehesa Mediterranean grasslands, in spite of their great biological diversity and the high O3 levels recorded in the region. A screening study was carried out in open-top chambers (OTCs) to assess the O3-sensitivity of representative therophytes of these ecosystems based on the response of selected growth-related parameters. Three O3 treatments and 3 OTCs per treatment were used. Legume species were very sensitive to O3, because 78% of the tested species showed detrimental effects on their total biomass relative growth rate (RGR) following their exposure to O3. The Trifolium genus was particularly sensitive showing O3-induced adverse effects on most of the assessed parameters. Gramineae plants were less sensitive than Leguminosae species because detrimental effects on total biomass RGR were only observed in 14% of the assessed species. No relationship was found between relative growth rates when growing in clean air and O3 susceptibility. The implications of these effects on the performance of dehesa acidic grasslands and on the definition of ozone critical levels for the protection of semi-natural vegetation are discussed.
显示更多 [+] 显示较少 [-]A study of the impact of polluted sea-spray on needles of Pinus halepensis (The possible role of surfactants) 全文
1993
Richard, Béatrice
A study of the impact of polluted sea-spray on needles of Pinus halepensis (The possible role of surfactants). 1.Air Pollution Research 2. Status Seminar of Tree Physiological Projects
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