Batch adsorption experiments were carried out to study the adsorptive removal and diffusion mechanism of para-chlorophenol (p-CP) onto Calgon Filtrasorb 400 (F400) activated carbon. The external mass transfer resistance is negligible in the adsorption process carried out under different conditions in batch operation. Intraparticle diffusion model plots were used to correlate the batch p-CP adsorption data; three distinct linear sections were obtained for every batch operation. The textural properties of F400 activated carbon showed that it has a large portion of supermicropores, which is comparable to the size of the p-CP molecules. Due to the stronger interactions between p-CP molecules and F400 micropores, p-CP molecules predominantly diffused and occupied active sites in micropore region by hopping mechanism, and eventually followed by a slow filling of mesopores and micropores. This hypothesis is proven by the excellent agreement of the intraparticle diffusion model plots and the textural properties of F400 activated carbon.

International audience

International audience

In Portugal, Atlantic codfish (Gadus morhua) is usually consumed after dry salting; this process is carried out by mixing deboned codfish with food-grade marine salt followed by stacking in a tank for 6 days. Along the salting process, codfish incorporates salt as well as it is partially dried by the release of water - up to 22 % (w/w). Currently, this wastewater is treated as a residue not being further valorized. However, the presence of a significant amount of valuable compounds in this rest, such as amino acids and proteins, may allow for valorization opportunities not yet explored. The present work focuses on the identification of the nitrogen-containing compounds present in such wastewater. Total nitrogen (WSN), trichloroacetic acid-soluble nitrogen (TCASN) and phosphotungstic acid-soluble nitrogen (PTASN) were evaluated by the micro-Kjeldahl method; Biuret method was used for total protein determinations and SDS-Page was performed for protein molecular weight screening. The results revealed an increase of WSN, TCASN and PTASN with time, with corresponding values of 3.17 g/L (WSN), 1.62 g/L (TCASN) and 1.16 g/L (PTASN) by the end of the process; the evolution of WSN versus the released water was approximately constant during the salting process, as well as the ratios of TCASN/WSN and PTASN/WSN with values of 51.25 and 36.55 % (w/w) at equilibrium, respectively.

conférence invitée (Key lecture)<br/>conférence invitée (Key lecture) | In France, 330 106 tons of organic wastes coming from agriculture (animal manure), industries and urban communities, are yearly recycled on cultivated soils (average of 11 ton/ha year on all the cultivated soils). Most manure have been always returned to soils but only 13% of the urban wastes on a total of potential 30 to 40% are recycled in agriculture. The French regulation requests the increase of composting and recycling up to 35% in 2012 and 45% in 2015. On the other hand, the decrease of organic matter content in soil is one of the threats towards soils that European Union has retained in the preparation of the Soil Directive regulation to control soil quality and prevent soil degradation. On the other hand in France, agriculture is geographically distributed and in many areas animal breeding has disappeared. In these regions, urban composts or other kinds of organic wastes represent valuable sources of organic matter for soils. In order to favour the development of recycling of organic wastes in agriculture, their agronomic value must be better known and their potential environmental impacts monitored in long-term field experiments. The presentation will focus on the effect of repeated organic waste application on potential carbon storage in soil and its simulation and on the control of organic pollutant potentially present in the organic wastes. Up to 60% of the applied organic carbon can be stored in soil and the potential efficiency of organic waste can be predicted based on their biochemical composition. Some persistent organic pollutants (PAH, PCB) and other more easily biodegradable (Nonylphenols, Phtalates and Linearalkylbenzene sulfonates) have been also measured in organic amendments, soil and crops in the field experiments and no accumulation have been observed. The waste treatments should be optimized to favour their dissipation before application. A model has been developed to simulate both organic matter and organic pollutant dynamics during waste composting

Current predictions as to the impacts of climate change in general and Arctic climate change in particular are such that a wide range of processes relevant to Arctic contaminants are potentially vulnerable. Of these, radioactive contaminants and the processes that govern their transport and fate may be particularly susceptible to the effects of a changing Arctic climate. This paper explores the potential changes in the physical system of the Arctic climate system as they are deducible from present day knowledge and model projections. As a contribution to a better preparedness regarding Arctic marine contamination with radioactivity we present and discuss how a changing marine physical environment may play a role in altering the current understanding pertaining to behavior of contaminant radionuclides in the marine environment of the Arctic region.

A field survey was conducted on two intensive shrimp farms using similar technical practices: one (DF) historically affected by a vibriosis, the other (HC) in which the pathogen has been observed although no mortality event has occurred. Because historical data suggest that eutrophication process may directly or indirectly play a role in the disease outbreak, we focussed our research on its dynamics. A higher variability of the phytoplanktonic compartment linked to an imbalance in the molar N:P ratio was observed in farm DF compared to farm HC, implying a modification on the linkage between the bacteria and phytoplankton compartments at DF. The beginning of the mortality outbreak at DF followed a shift from picoto nanophytoplankton. The organic matter mineralization process at the water-sediment interface may explain the disturbance observed in the water column during eutrophication. The consequences of this disturbance on shrimps' health status and pathogen ecology are discussed. (C) 2009 Elsevier Ltd. All rights reserved.

The impact of autochthonous anaerobic bacteria on the release of metals in river sediment was studied. The sediments were characterized and bacterial activity was monitored in a batch reactor, where the sediments were incubated with a synthetic substrate solution containing glucose as carbon source. The results showed that metal release was correlated to the bacterial growth (carbon mineralization). In particular, a relationship between iron reduction and metal release was observed indicating that iron-reducing bacteria had a strong influence. By reductive dissolution of iron oxides, bacteria also released their associated toxic elements into the liquid phase. While organic analysis showed acetate and butyrate production leading to a decrease in pH and indicating a Clostridium fermentative bacteria activity, the results did not indicate any direct role of organic acids in the dissolution of iron and their associated metals.

The uptake, elimination and transformation of six PBDE congeners (BDE-28, -47, -99, -100, -153, -209) were studied in juvenile common sole (Solea solea L) exposed to spiked contaminated food over a three-month period, and then depurated over a five-month period. Methoxylated (MeO-) and hydroxylated (OH-) PBDEs were determined in fish plasma exposed to PBDEs and compared to those obtained in control fish. While all MeO- and some OH- congeners identified in fish plasma were found to originate from non-metabolic sources, several OH- congeners, i.e., OH-tetraBDEs and OH-pentaBDEs, were found to originate from fish metabolism. Among these, 4 '-OH-BDE-49 was identified as a BDE-47 metabolite. Congener 4 '-OH-BDE-101, identified here for the first time, may be the result of BDE-99 metabolic transformation. Our results unequivocally showed that PBDEs are metabolised in juvenile sole via the formation of OH- metabolites. However, this was not a major biotransformation route compared to biotransformation through debromination. (C) 2010 Elsevier Ltd. All rights reserved.