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In the context of the global energy transition, renewable and sustainable resources are increasingly being explored as an alternative to fossil fuels. Lignocellulosic and organic waste biomass is abundant, low-cost, and represents a promising feedstock for bioenergy production. However, the valorization of abandoned or underutilized residues remains largely unexplored. This study evaluated the bioenergy potential of eight solid organic waste materials collected from abandoned sites, including: (1) landfilled woodwaste, (2) softwood and (3) hardwood sawdust, (4) fresh pine bark (5) decomposed pine bark, (6) decomposed leaf and yard waste, (7) decomposed organic food waste (8) and aged barn dust. Physicochemical characterization revealed their high organic matter content across all substrates, with volatile solids (VS) ranging from 40% to 95%, whereas the C/N ratio varied widely from 10 to 1297. To optimize conditions, co-digesting was performed at a fixed substrate-to-inoculum ratio (SIR) at 1, which effectively balanced the high carbon content and enhanced process stability. Under thermophilic anaerobic digestion, organic matter degradation ranged from 16% to 71%. The highest specific methane potential reached 89.9 ± 7.7 L CH4·kg VS added−1 for fresh pine bark, while the lowest was 25.2 ± 6.8 L CH4·kg VS added−1 for decomposed organic food waste. The resulting digestates were rich in nutrients, demonstrating high agronomic value. Anaerobic digestion of abandoned lignocellulosic and organic residues presents a dual benefit: it reduces pollution while producing renewable energy in the form of methane and valuable by-products that can be used as fertilizers, thereby ensuring a circular economy. This study demonstrates the significant potential of utilizing overlooked waste streams as valuable resources in sustainable bioenergy generation.
Situé dans une doline sur le Causse Noir, à une dizaine de kilomètres au nord-est de Millau, le petit abri de Combe-Grèze a d'abord été fouillé dans la seconde moitié du xxe siècle, puis a fait l'objet d'un récent retour sur le terrain par les auteurs du présent article. Ce site, occupé à différents moments de l'Holocène, a été largement mobilisé dans les scénarios de néolithisation des arrière-pays. Cependant, les travaux de terrain conduits depuis quelques années à l'extérieur de l'abri et un retour sur les collections anciennes permettent de nuancer nettement les interprétations anciennes, mettant notamment en évidence l'existence de nombreux problèmes de mélanges d'occupations. Ainsi, nous proposons ici une réactualisation des données disponibles concernant ce gisement, notamment pour ce qui concerne la nature des occupations, la chronologie, les productions matérielles issues des différentes occupations, les ressources exploitées et la précision du cadre paléo-environnemental.
The small shelter of Combe-Grèze, located in a dolina of the Causse Noir plateau about ten kilometres northeast of Millau in Southwestern France, was first excavated in the second half of the 20th century, and more recently has been subject to new investigations by the authors of this contribution. The site was repeatedly occupied during the Holocene and has been widely referred to in neolithisation scenarios regarding the Mediterranean hinterlands. However, fieldwork carried out over the last few years in the area outside the shelter and the reevaluation of ancient collections stemming from the site have largely modified previous interpretations and evidenced that the site reveals a palimpsest of occupations. We therefore propose here an updating of the available data concerning the site, more particularly with regard to the nature of its occupational stages, its chronology, and the material production associated with the different occupations, the exploited resources, and the palaeoenvironmental reconstructions.
Les problemes d’integration des enseignantes sont tres documentes au Burkina Faso et nous ne l’avons constate que fortuitement, lors d’une enquete sur la formation continue des enseignants du primaire. Les conditions d’integration de la femme dans les spheres du systeme educatif ont des similitudes, mais aussi des differences specifiques a chaque pays. Notre analyse par theorisation ancree nous a permis de degager quatre categories que nous presentons et discutons : les benefices de la presence des femmes enseignantes dans les zones rurales, les obstacles lies au lieu d’affectation, a leur situation matrimoniale et leurs effets cumules sur leur vie professionnelle.
