320 research outputs found
Gender stereotypes and empowerment of women in energy cooperatives : a comparative analysis from Italy and Belgium
Spółdzielnie energetyczne odnotowują znaczny wzrost w całej Unii Europejskiej. Jednak pomimo chęci integracji i wspierania różnorodności, reprezentacja kobiet w spółdzielniach energetycznych jest nadal ograniczona. Przedstawione badanie ma na celu zweryfikowanie siły stereotypów związanych z płcią w spółdzielniach energetycznych oraz, w przypadku kobiet, czynników, z którymi stereotypy te są powiązane. Dane zostały zebrane w dwóch spółdzielniach, ènostra we Włoszech i Ecopower w Belgii, razem od 5690 respondentek i respondentów. Oprócz tego, że są to jedne z najważniejszych spółdzielni w swoich krajach, stanowią one interesujący przypadek porównawczy, ponieważ w ènostra zarówno kobiety, jak i mężczyźni są prawie równo reprezentowani, a prezeską jest kobieta, podczas gdy w Ecopower kobiety są niedostatecznie reprezentowane, a zarząd jest zdominowany przez mężczyzn. Uzyskane wyniki sugerują, że w przypadku obu spółdzielni kobiety miały niższą samoocenę wiedzy na temat energii niż mężczyźni i że bardziej niż mężczyźni uznawały znaczenie obecności kobiet w zarządzie. Pozwoliły nam również stwierdzić, że kobiety kierujące się silniejszymi stereotypami ze względu na płeć na temat energii wykazywały niższą samoocenę wiedzy, ale większą tendencję do jej zwiększania po przystąpieniu do spółdzielni i przypisywały nieco większe znaczenie obecności kobiet w zarządzie spółdzielni.Energy cooperatives are witnessing substantial growth across the European Union. However, despite the desire to be inclusive and to foster diversity, the representation of women in energy cooperatives is still limited. The study aimed to verify the strength of the endorsement of gender stereotypes within energy cooperatives and, in the case of women, the factors stereotypes are associated to. Data were collected in two cooperatives, ènostra in Italy and Ecopower in Belgium, for a total of 5690 respondents. Apart from being among the most important cooperatives in their respective countries, the two represent an interesting comparative case because in ènostra women and men are almost equally represented and the president is a woman, while in Ecopower women are underrepresented and the board of directors is male-dominated. For both cooperatives, the results suggested that women had lower self-assessment of knowledge about energy than men and that they recognised, more so than men, the importance of the presence of women on the board of directors (BoD). Finally, we found that women with stronger gender stereotypes about energy exhibited lower self-assessment of knowledge but a greater tendency to increase it after joining the cooperative and they attributed slightly more importance to the presence of women on the cooperative BoD
Biohydrogen production from food waste: Influence of the inoculum-to-substrate ratio
In this study, the influence of the inoculum-to-substrate ratio (ISR) on dark fermentative hydrogen production from food waste (FW) was evaluated. ISR values ranging from 0.05 to 0.25 g VSinoculum/g VSsubstrate were investigated by performing batch tests at T = 39 °C and pH = 6.5, the latter being the optimal value identified based on a previous study. The ISR was found to affect the fermentation process, clearly showing that an adequate ISR is essential in order to optimise the process kinetics and the H2 yield. An ISR of 0.14 proved to optimum, leading to a maximum H2 yield of 88.8 L H2/kg VSFW and a maximum production rate of 10.8 L H2/kg VSFW∙h. The analysis of the fermentation products indicated that the observed highest H2 production mostly derived from the typical acetate/butyrate-type fermentation
Efficient Nitrogen Recovery from Agro-Energy Effluents for Cyanobacteria Cultivation (Spirulina)
The present study aimed to obtain an efficient liquid nitrogen fertilizer from the by-product of anaerobic digestion for its subsequent use in the production of cyanobacteria (Spirulina). A simple recovery technology was tested based on the stripping and acid absorption, modifying temperature (50 and 70 degrees C) and pH (10 and 12), of the ammonia nitrogen contained in the digestate produced in a large-scale plant treating livestock manure and grass silage. The results demonstrated how, at a relatively low temperature (50 degrees C), using sulfuric and citric acid solution, it is possible to recover nitrogen from a digestate in the form of ammonium sulfate and ammonium citrate with yields of 70% and 72.1% respectively. By carrying out Spirulina growth tests, promising results were obtained under semicontinuous production, with a maximum dry biomass daily productivity of 0.344 g L-1 day(-1) with ammonium sulfate and 0.246 gDW L-1 day(-1) with ammonium citrate. The results showed that nitrogen can be efficiently recovered on site by using the organic acid, digestate and waste heat from anaerobic digestion for Spirulina biomass production
Produzione biologica di idrogeno da miscele di residui
2008-11-25Aula Magna Facoltà di Ingegneria, CagliariLo stato dell’arte della ricerca scientifica nel settore della produzione di energia da biomass
An outlook on modern and sustainable approaches to the management of grape pomace by integrating green processes, biotechnologies and advanced biomedical approaches
Grape pomace is the main solid residue of wine industry, mainly composed of seeds, skins and stalks, all containing high amounts of valuable phytochemicals. Considering its high potential, in this review, an outlook on different resources and products, which can be obtained by the recovery of grape pomace is provided. Special attention has been devoted to the analysis of chemical, physical and biotechnological processes to be applied and also to the high value compounds and products, such as supplements, nutraceuticals and cosmeceuticals, that can be manufactured. In particular, in the first part of the review, an update on the composition of grape pomace has been provided along with the analysis of its traditional fate. In the second part, the more modern and green approaches tested to the sustainable management of grape pomace are reported and discussed
Trends and perspectives in the use of organic acids for critical metal recycling from hard-metal scraps
Hard-metal sector, strategic for the industrial economies, is suffering from the reduced availability and price volatility of its main feedstock: critical W and Co. In 2021, a 73.5 kt W and 9.2 kt Co demand for hard-metal production (65% and 5.3% of global demand, respectively), was recorded. Hard-metal scrap recycling is hence desirable for both environmental and economic reasons. A significant recovery of W and Co from manufacturing by-products and scraps is already good practice in the hard-metal industry (42% for W and 22% for Co). However, there is still a lot to do to meet the technical-economic-environmental sustainability in materials and energy enhancement for pursuing a green economy model. Indeed, Chemical Modification and Direct Recycling, which are the most widely employed industrial approaches, typically involve energy and/or harsh chemicals-intensive treatments which require expensive equipment and skilled workers. In the last decade, research efforts have been spent on implementing alternative materials reclamation processes from hard-metal scraps based on the use of bio-based organic acids with the view to increase the rate and quality of the recycled materials exploiting their peculiar metal complexing action as well as to preserve natural resources and prevent the disposal of potentially toxic/polluting substances. Despite the preliminary stage of the research, organic acids were demonstrated to be powerful but gentle agents for the selective leaching of cobalt from WC-Co-based materials as well as promising agents for WO3 dissolution. Indeed, thanks to their acid and complexing properties, they can stabilize metals in their oxidized form giving soluble products and preventing passivation phenomena. Furthermore, organic acids can be obtained by renewable biomass transformation, limiting the request for high-impact industrial chemicals. Hence they points out key features making them promising for the design of eco-friendly recovery processes. In this context, the different industrial approaches to the recovery and recycling of Hard-metal wastes, with specific reference to the role of bio-derived organic acids in hydro- and solvo-metallurgical processes, will be critically reviewed with the view of opening a discussion on the perspectives of their use in designing circular economy models in HM manufacturing as economically, technically and environmentally sustainable as possible
Disposable Mater-Bi® bioplastic tableware: Characterization and assessment of anaerobic biodegradability
In this study commercial starch-based (Mater-Bi®) disposable bioplastic tableware items, which are among the most widely used commercial products available on the market, were selected for lab-scale anaerobic degradability tests. Since the knowledge of the biodegradation profile of bioplastic products is still incomplete, the study was aimed at investigating the maximum biodegradation potential of the materials under ideal anaerobic conditions, as well as the biodegradability degree as a function of treatment time. The experiments were carried out under mesophilic and thermophilic conditions at different food to microorganism ratios and test material sizes, and the specific biogas production and associated kinetics were evaluated. Biogas production was observed only under thermophilic conditions, with conversion yields in the range 602–898 mL/gTOC for the tested cups and 1207 ± 52.8 mL/gTOC for the knives. The degrees of biodegradation and disintegration were found to be strongly dependent on the product composition. Physical, chemical and morphological analyses were used to characterize the tested materials before and after the degradation and potential correlations among process parameters and bioplastic characteristics were derived
Combining Different Approaches for Grape Pomace Valorization: Polyphenols Extraction and Composting of the Exhausted Biomass
Grape pomace represents 60%, by weight, of the solid side-streams of the wine-making process. The quantities produced, seasonality, and the presence of polyphenols pose economic and environmental issues that require proper management approaches based on the principles of sustainability and circular economy. The present work focuses on the combined application of solid-liquid extraction of polyphenols from ground grape pomace using a hydroethanolic mixture and the composting of the exhausted pomace. The obtained results support the possibility of recovering approximately 76.5 g of extract per kg of dry grape pomace (or 1.8 g of total phenols per kg of dry grape pomace). The composting process was not affected by the extraction process. On the contrary, the composting process was enhanced by the pomace particle size reduction, in terms of final biostability and content of humic acids
A Case Study of Implementation of Circular Economy Principles to Waste Management: Integrated Treatment of Cheese Whey and Hi-Tech Waste
In a global context characterized by severe environmental problems and increasing resource scarcity, waste represents both a challenge and an opportunity. This study aims to demonstrate with a real case the potential for optimizing the waste valorization action attainable through the synergic application of different treatments to residues of equally different nature and origin. In particular, bio-chemical (dark fermentation), chemical-physical (selective leaching) and thermo-chemical (hydrothermal carbonization) treatments were applied for the integrated valorization of whey from sheep cheese production and Hi-Tech waste (discarded electrical and electronic equipment). The treatments were applied at a laboratory scale on real samples of these residues. The organic acids used for selective leaching of valuable metals from Hi-Tech waste were obtained by dark fermentation of the cheese whey, while hydrothermal carbonization was used to convert the waste from previous stages into hydrochar feasible as solid fuel or soil improver. The dark fermentation tests have highlighted the possibility of recovering ≈ 100 g of organic acids from 1 L of whey; furthermore, it is also possible to recover bio-hydrogen depending on the operating conditions applied and the type of targeted organic acids. The leaching tests have demonstrated how the organic acids from whey fermentation have selective and quantitative mobilization capacities comparable to those of the same acids available on the market. The carbonization tests produced carbon-enriched hydrochar with promising fuel properties, as well as process waters suitable for anaerobic digestion with methane production. The results of the project led to the filing of an international patent
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