The modalities of REDD+ to encourage a sustainable transition of the small farmers in São Felix do Xingu (Pará, Brésil) : Towards a consideration of the actors' diversity

Although the Brazilian Federal regulation approach against deforestation has been effective with large landowners, it has little touched smallholders and may have aggravated their poverty conditions. In this context, REDD+ is seen by many institutions as a useful tool to promote conservation by small farmers, as it could encourage a transition towards alternatives livelihoods, which would reduce deforestation. In the context of a REDD+ pilot project in São Felix do Xingu, we aimed at analysing the perceptions of deforestation by small farmers and what would bring them to stop. We concluded that an investment-based scheme might be more effective than a use-restricting payment, given that support in the form of technical assistance is essential for most of them. More specifically three groups are identified: the environmentalists, the innovators and the objectors. They each have very different needs to reduce deforestation, questioning the relevance of one-fits-it-all solutions even for an investment scheme. A REDD+ project would have to adapt to this diversity by offering various forms of support. This has implications both for the equity within a REDD+ project and the control of conditionality.( Résumé d'auteur

Performances des stations de pompages en irrigation : application aux forages de petits périmètres irrigués de la plaine de Kairouan (Tunisie) et impact des dysfonctionnements sur le prix de l'eau

International audienceLorsqu'une élévation de l'eau de nappes ou une mise en pression est nécessaire au fonctionnement des systèmes modernes d'irrigation dans un périmètre, on utilise presque exclusivement des pompes centrifuges. La facture énergétique représente donc une part importante du coût de l'eau. Or, le rendement de ces machines est très dépendant de leurs conditions de fonctionnement et de leur usure et toute déviation par rapport aux conditions optimales entraîne des surcoûts énergétiques importants. L'objectif est de proposer une méthodologie pour évaluer les performances de ces équipements. Des indicateurs accessibles (énergie unitaire, énergie volumique absorbée réelle, volume spécifique pompé, coefficient de volume spécifique pompé) sont définis et des valeurs de référence fournies à partir des données des constructeurs. Les différentes méthodes d'estimation des volumes pompés sont critiquées. Les tests proposés sur les données volumiques indiquent le type de mesure réalisé pour les volumes pompés ainsi que leur dérive dans le temps (utilisation du débit nominal, compteur volumétrique). Pour les mesures d'énergie, l'absence de synchronisation entre les relevés temporels et énergétiques implique de cumuler les données pour obtenir la puissance consommée - lors de conditions stables de fonctionnement des pompes et si chaque pompe dispose d'un compteur d'énergie. Un ensemble de 18 stations de pompage sur forage alimentant des petits périmètres irrigués de la plaine de Kairouan en Tunisie centrale a été testé. La vétusté des équipements peut engendrer des rendements très faibles dont la conséquence principale est une augmentation des coûts de pompage (consommation énergétique et surcoût de maintenance). Ce diagnostic met donc bien en évidence l'intérêt d'un suivi précis de chaque ouvrage. Les divergences observées dans les ratios entre les volumes pompés et l'énergie consommée par rapport à ceux attendus en conditions optimales de fonctionnement conduisent au raisonnement suivant : si les données obtenues sont justes, le dysfonctionnement provient de l'inadaptation de l'équipement hydroélectrique au fonctionnement hydraulique de l'installation ; ou bien si les données sont fausses, ce dysfonctionnement provient des erreurs de gestion des pompistes et les quantités d'eau pompées sont alors sous-estimées. Dans les deux cas, un surcoût est payé par l'Administration. Dans la moitié des stations, les surcoûts d'énergie dépassent 20 %, voire 50 % pour près du quart d'entre elles

Life cycle assessment of Polychlorinated Biphenyl contaminated soil remediation processes

Goal and scope. A life-cycle assessment (LCA) was performed to evaluate the environmental impacts of the remediation of industrial soils contaminated by polychlorobiphenyl (PCB). Two new bioremediation treatment options were compared with the usual incineration process. In this attributional LCA, only secondary impacts were considered. The contaminated soil used for the experiments contained 200 mg of PCB per kg. Methods. Three off-site treatments scenarios were studied: 1) bioremediation with mechanical aeration, 2) bioremediation with electric aeration and 3) incineration with natural gas. Bioremediation processes were designed from lab-scale, scale-up and pilot experiments. The incineration technique was inspired by a French plant. A semi-quantitative uncertainty analysis was performed on the data. Environmental impacts were evaluated with the CML 2001 method using the Simapro software program. Results and discussion. In most compared categories, the bioremediation processes are favorable. Of the bioremediation options, the lowest environmental footprint was observed for electric aeration. The uncertainty analysis supported the results that compared incineration and bioremediation but decreased the difference between the options of aeration. The distance of transportation was one of the most sensitive parameters, especially for bioremediation. At equal distances between the polluted sites and the treatment plant, bioremediation had fewer impacts than incineration in eight out of thirteen categories. Conclusions. The use of natural gas for the incineration process generated the most impacts. Irrespective of the aeration option, bioremediation was better than incineration. Recommendations. The time of treatment should be taken into account. More precise and detailed data are required for the incineration scenario. More parameters of biological treatments should be measured. LCA results should be completed using ecological and health risk assessment and an acceptability evaluation

Nitrate reducing bacterial activity in concrete cells of nuclear waste disposal

Leaching experiments of solid matrices (bitumen and cement pastes) have been first implemented to define the physicochemical conditions that microorganisms are likely to meet at the bitumen-concrete interface (see the paper of Bertron et al.). Of course, as might be suspected, the cement matrix imposes highly alkaline pH conditions (10 < pH < 11). The screening of a range of anaerobic denitrifying bacterial strains led us to select Halomonas desiderata as a model bacterium capable of catalyzing the reaction of nitrate reduction in these extreme conditions of pH. The denitrifying activity of Halomonas desiderata was quantified in batch bioreactor in the presence of solid matrices and / or leachate from bitumen and cement matrices. Denitrification was relatively fast in the presence of cement matrix (< 100 hours) and 2 to 3 times slower in the presence of bituminous matrix. Overall, the presence of solid cement promoted the kinetics of denitrification. The observation of solid surfaces at the end of the experiment revealed the presence of a biofilm of Halomonas desiderata on the cement paste surface. These attached bacteria showed a denitrifying activity comparable to planktonic bacterial culture. On the other side, no colonization of bitumen could be highlighted as either by SEM or epifluorescence microscopy. Now, we are currently developing a continuous experimental bioreactor which should allow us a more rational understanding of the bitumen-cement-microbe interactions

Phenotypic Landscape of Saccharomyces cerevisiae during Wine Fermentation: Evidence for Origin-Dependent Metabolic Traits

The species Saccharomyces cerevisiae includes natural strains, clinical isolates, and a large number of strains used in human activities. The aim of this work was to investigate how the adaptation to a broad range of ecological niches may have selectively shaped the yeast metabolic network to generate specific phenotypes. Using 72 S. cerevisiae strains collected from various sources, we provide, for the first time, a population-scale picture of the fermentative metabolic traits found in the S. cerevisiae species under wine making conditions. Considerable phenotypic variation was found suggesting that this yeast employs diverse metabolic strategies to face environmental constraints. Several groups of strains can be distinguished from the entire population on the basis of specific traits. Strains accustomed to growing in the presence of high sugar concentrations, such as wine yeasts and strains obtained from fruits, were able to achieve fermentation, whereas natural yeasts isolated from “poor-sugar” environments, such as oak trees or plants, were not. Commercial wine yeasts clearly appeared as a subset of vineyard isolates, and were mainly differentiated by their fermentative performances as well as their low acetate production. Overall, the emergence of the origin-dependent properties of the strains provides evidence for a phenotypic evolution driven by environmental constraints and/or human selection within S. cerevisiae