This work presents experimental data and modelling of the release of Mo from high-burnup spent nuclear fuel (63 MWd/kgU) at two different pH values, 8.4 and 13.2 in air. The release of Mo from SF to ...the solution is around two orders of magnitude higher at pH = 13.2 than at pH = 8.4. The high Mo release at high pH would indicate that Mo would not be congruently released with uranium and would have an important contribution to the Instant Release Fraction, with a value of 5.3%.
Parallel experiments with pure non irradiated Mo(s) and XPS determinations indicated that the faster dissolution at pH = 13.2 could be the consequence of the higher releases from metallic Mo in the fuel through a surface complexation mechanism promoted by the OH− and the oxidation of the metal to Mo(VI) via the formation of intermediate Mo(IV) and Mo(V) species.
► Decentralized grey water treatment by MBR prototype was performed for water recycling. ► Treatment comprises: screening, biological oxidation, filtration and disinfection. ► Organic, surfactants ...and microbial parameters were under urban water reuse criteria. ► Disinfection is required to avoid health risk in storage and potential application. ► 430m3/year of potable water are potentially saved in toilet flushing application.
Grey water treatment and reuse for non-drinking water requirements has become of great interest in arid and semi-arid zones where water resources are becoming both quantitatively and qualitatively scarce. In this study a decentralized and automatic MBR prototype has been designed and installed in the REMOSA facilities for treatment of low-load grey water to be recycled in flushing-toilet application. The recycling treatment of grey water comprises four stages: screening, biological oxidation, filtration and a final disinfection by chlorination. The influent and effluent were monitored in order to determine the treatment efficiency and assessment of the quality potential of treated grey water. The results obtained indicate that recycling of grey water allows an effluent of excellent quality with organic, surfactants and microbial parameters under the limits defined by Spanish legislation for urban water reuse. The disinfection of treated grey water is required to ensure compliance with microbial standards and to avoid the health risk in storage and application of recycled water.
•Common social hotspots of supply chains of case studies are: China, India and Congo.•Areas of concern were “Occupational accidents rate” and “Organizational support for community initiatives”.•SLCA ...is a useful tool for companies to improve corporate social sustainability.•The structure of Social Hotspot Database limits the hotspot analysis level results.
Environmental pollution, resource scarcity, and freshwater shortage are critical world challenges facing humanity. Process industry produces large amounts of brine, a waste water with a high salinity level and often critical raw materials. This study applies the social life cycle assessment (S-LCA) to quantify societal benefits and risks in developing brine treatment systems. S-LCA is implemented for hotspot and site-specific levels on four case studies of the Zero Brine project. Hotspot analysis focused on the major commodities. Social Hotspot Database was used as source for data and endpoint indicators. In addition, site-specific analysis regarded the social performance of the case studies companies; interviews and questionnaires were performed with representatives of the four case studies. The collected data were converted to scores with subcategory assessment method and performance reference points. The results show that for all case studies “Labor rights and decent work” and “Health and safety” indicators result in the largest impacts due to imports of commodities from developing countries. Site-specific results show that the overall social sustainability performance of the case study companies is at a good level. The only potential areas for improvement are the “Occupational accidents” and “Contribution to the local community”. The former are minimally higher for silica plant and higher for coal mine in relation to these sectors average accidents rates. Furthermore, the coal mine company can contribute more to the local community and reduce conflicts concerning environmental impacts at the city level. Common identified hotspots among the case studies are: China, India and Congo. Reducing imports from these countries will significantly improve the societal performance of the brine systems.
•The socio-economic aspects of plasma gasification were assessed.•A comparison to the conventional incineration option was performed.•A hybrid importance-fulfilment matrix combining different aspects ...was developed.•Plasma gasification depicted high capital costs while enabling higher revenues.•The technical aspects were the most significant and the social sphere ranked last.
Fossil fuels contribute to climate changes, negatively affecting the environment. Waste has been seen as a possible resource for energy production, constituting a cleaner alternative to replace non-renewable fuels through waste-to-energy (WtE) techniques. Plasma gasification is a procedure that decomposes the molecules at high temperatures, affording a synthetic gas (syngas) that can further produce electricity, fuels and chemicals. Within the most used WtE technologies, plasma gasification is recent and therefore not yet widely applied. Thus, a viability study to support the thorough understanding and implementation of this treatment is required.
This paper assesses the socio-economic aspects of plasma gasification promoting a more sustained waste management system, also taking advantage of the commodity assets granted by the technique. To the best of the authors’ knowledge, this is the first time that an importance-fulfilment matrix is specifically developed to appraise the socio-economic viability of plasma gasification, combining environmental, technical, economic and social aspects. Although depicting high capital costs, plasma gasification enabled high revenues, rebating the operational costs. The sensitivity analysis exhibited a descending impact in the profitability of the plant for varying electricity sales price, landfill fee, discount rate, vitrified slag sales price and initial investment.
Catalonia is one of the most important world producers of cork, a natural material from which wine stoppers, champagne stoppers and derived products are produced. Within this process, approximately ...15% of the extracted raw cork ends up as forestry waste, while considerable shares of the processed cork are also considered cork residues, as for instance defective stoppers or agglomerate plates. Indeed, cork residues are usually sent to landfill with no recovery or second use.
In this study, gasification is used as a thermal strategy to convert cork wastes into energy, in order to demonstrate the valorisation of cork waste. This contributes to the implementation of the Waste Framework Directive (2008/98/CE) following the objectives and goals of the Roadmap for a Resource-Efficient Europe. Technological, R&D and industrial partners were gathered under the framework of the LIFE + Ecorkwaste Project and thus, a gasification plant with capacity to treat 15 kg of cork residues per day was designed. The ultimate goal was to develop and optimize the experimental procedure so that the gasification plant could be implemented at an industrial scale. In order to assess the environmental, techno-economic and social impacts of this technology, life cycle assessment (LCA) and life cycle cost (LCC) were performed, as well as a socio-economic matrix integrating various aspects of the technique was developed. The functional unit was the production of 1 MWh by means of cork valorisation through gasification technology and a comparison with the conventional scenario of using the national electricity grid was performed. Three scenarios of possible management strategies for the produced wastes were modelled for the LCA using Simapro Developer and two scenarios of different operation regimes were considered for the LCC under the CAPEX-OPEX concept. As main findings it was shown that the gasification strategy has a sustainable profile with lower environmental impacts than the conventional scheme of energy production. Moreover, this thermal scheme entails lower costs than the conventional scheme and allows net savings in the order of several hundred thousand €, for a 20-year lifespan of the plant.
•Gasification is used as a thermal strategy to convert cork wastes into energy.•Life cycle and cost analysis are rendered for environmental and economic appraisal.•Char valorisation depicted the most sustainable profile, amongst other scenarios.•Social features were infered wihin environmental, technical and economic aspects.•Landfill reduction and clean energy production supported circular economy.
Display omitted
•This study reviewed the effect of biomass type on the properties of biochar.•The biomass composition significantly impacted biochar specifications.•Pyrolysis condition was a key ...parameter influencing biochar properties.•Suggestions are given to obtain biochar of desired property.
Owing to the diversity of biomasses and many variables in pyrolysis process, the property of biochar from varied biomass feedstock or even same biomass could differ significantly. Since the property of biochar governs the further application of biochar, this review paid particular attention to the correlation between the nature of biomass feedstock and the specifications of biochar in terms of yield, elemental composition, pH, functionalities, heating value, pore structures, morphologies, etc. The property of the biochar from the pyrolysis of cellulose, hemicellulose, lignin, woody biomass (pine, mallee, poplar, acacia, oak, eucalyptus and beech), bark of woody biomass, leaves of woody biomass, straw, algae, fruit peels, tea waste was compared and summarized. In addition, the differences of the biochar of these varied origins were also analyzed. The remaining questions, about the correlation of biomass nature with biochar characteristics, to be further investigated are analyzed in detail. The deduced information about the relationship of the nature of biochar and biomass feedstock as well as key pyrolysis parameters is of importance for further development of the methods for tailoring or production of the biochar of desirable properties. The results from this study could be interesting technically and commercially for the technology developer using biochar as the source of carbon in different applications.
A prototype pilot plant testing for a novel complete treatment strategy for landfill leachate aimed to decrease its environmental impact was studied. Pre-treatment of leachate was performed by means ...of a membrane bioreactor (MBR) decreasing inorganic carbon concentration by 92 ± 8% and achieving N removals of 85%. Suspended solids removal in the MBR >99.9% conditioned leachate for the next membrane step. Spiral-would reverse osmosis (RO) regenerated membranes were used to treat the MBR effluent. This RO unit achieved a global recovery of 84% along with operation and rejections of >95% for most of the analyzed compounds. Since RO permeate did not meet discharge standards, promising results were obtained after a second RO pass was applied. The RO brine produced was further concentrated by an electrodialysis reversal (EDR) unit, achieving an averaged recovery of 67% throughout the operation. The average recovery of the whole pilot plant system was >90%. The reduction of global brine volume together with the use of regenerated membranes are key to the environmental impact of the process and contribute to closing the loop of the circular economy. Life Cycle Assessment (LCA), performed according to ILCD Handbook guidelines, demonstrated that proposed new treatment had lower environmental impact than conventional treatments currently used in landfill facilities. Concretely, for the nine impact categories evaluated, the proposed treatment presented an average impact reduction of 93% compared to an advanced oxidation system and an average reduction of 26% when compared to a conventional RO treatment.
Herein, it is aimed to investigate the effect of zeolite catalyst on the co‐pyrolysis process of waste tyre and poplar wood. A laboratory‐sized reactor is used to pyrolyze 15 g of sample at 500 °C ...under atmospheric pressure. In the results, it is indicated that co‐pyrolysis affects the properties of the products. Comparing to single feedstock, the co‐pyrolysis enhances the yields of bio‐oil, while reducing the formation of char. The pyrolysis of poplar wood produces 23.3 wt% of bio‐oil, while the pyrolysis of tyre yields 25 wt% of bio‐oil. However, it is 31.29 wt% for the co‐pyrolysis process. Higher content of valuable compounds are formed in the bio‐oil, which improve the fuel properties of the bio‐oil. The zeolite catalyst alters the characteristics of the products obtained from the co‐pyrolysis process. The gaseous products show a decrease in the concentrations of carbon monoxide and carbon dioxide when the catalyst is present. The liquid product analysis reveals the presence of light aromatics such as ethyl benzene and light linear compounds such as alkanes including octane, hexane, etc. The analysis of the catalysts suggests that a very small amount of coke deposits on the catalyst due to the slight increase in carbon content.
Herein, it is aimed to investigate the effect of zeolite catalyst on the co‐pyrolysis process of waste tyre and poplar wood. A laboratory‐sized reactor is used to pyrolyze 15 g of sample at 500 °C ...under atmospheric pressure. In the results, it is indicated that co‐pyrolysis affects the properties of the products. Comparing to single feedstock, the co‐pyrolysis enhances the yields of bio‐oil, while reducing the formation of char. The pyrolysis of poplar wood produces 23.3 wt% of bio‐oil, while the pyrolysis of tyre yields 25 wt% of bio‐oil. However, it is 31.29 wt% for the co‐pyrolysis process. Higher content of valuable compounds are formed in the bio‐oil, which improve the fuel properties of the bio‐oil. The zeolite catalyst alters the characteristics of the products obtained from the co‐pyrolysis process. The gaseous products show a decrease in the concentrations of carbon monoxide and carbon dioxide when the catalyst is present. The liquid product analysis reveals the presence of light aromatics such as ethyl benzene and light linear compounds such as alkanes including octane, hexane, etc. The analysis of the catalysts suggests that a very small amount of coke deposits on the catalyst due to the slight increase in carbon content.
Co‐pyrolysis of wood and tyre enhances the yield tar and improves its quality. The catalyst used shows high resistance in front of coke formation and upgrades the fuel properties of the tar.
