http://hdl.handle.net/10498/6842 2026-09-21T19:32:04Z http://hdl.handle.net/10498/39767 Radiological assessment of wastes from copper mining in Iberian Pyrite Belt Ramírez-Perez, Juan Antonio; Barba Lobo, Alejandro; Gázquez González, Manuel Jesús; Bolívar, Juan Pedro The Iberian Pyrite Belt (IPB), located in SW Spain, is the geographical area where more mining activities related to polymetallic minerals have been developed from around 4000 years before present, being especially intense from the second half of 19th century, generating huge amounts of wastes stored along the basins of the Odiel and Tinto rivers. According to the radiological European Union regulation, and the international one, the polymetallic mining is considered as a NORM (Naturally Occurring Radioactive Material) activity, and therefore, it is necessary to carry out an evaluation of the radiological risks associated with these mining activities. To achieve this objective the waste repositories of several mining areas were sampled trying to obtain the most representative wastes of the study area (roasted pyrite, floating mud, slags, leached pyrite, between others). The activity concentrations of natural radionuclides and multielement composition of the collected samples were measured, and different radiological indexes were calculated (Raeq, Hex, Ic, Fc238U and Fc232Th). The main conclusion of this work has been that all these indexes are below the threshold stablished by regulation to assure an effective dose smaller than 1 mSv per year, and therefore the mining waste deposited in the IPB can be used in valorization processes for building materials without radiological restrictions. 2025-07-11T00:00:00Z http://hdl.handle.net/10498/39573 Comparative Bibliometric Analysis of Biomethane Production from Anaerobic Digestion of Pig Slurry and Slaughterhouse Wastewater: Research Trends and Gaps Candel Pecellin, María; Fernández Rodríguez, Juana; Solera del Río, María del Rosario; Pérez García, Montserrat This bibliometric study evaluates scientific production between 2015 and 2025 inclusive on anaerobic digestion of pig slurry and slaughterhouse wastewater for biomethane generation. A total of 1.414 documents were identified for pig slurry and 250 for slaughterhouse wastewater, reflecting a marked imbalance in research attention. For pig slurry, the literature shows strong consolidation, with consistent focus on biogas yield optimization, emission mitigation, and agricultural valorization of digestate. By contrast, slaughterhouse wastewater research is comparatively limited, fragmented across technical case studies, and often concerned with process inhibition, pretreatment strategies, and integrated treatment systems. Despite this disparity, both residues are recognized as important feedstocks for renewable energy recovery, with co-digestion offering particular promise in terms of process stability and biomethane enhancement. 2025-11-01T00:00:00Z http://hdl.handle.net/10498/39359 Global trends and challenges in biogas purification and CO2 capture for renewable energy and climate mitigation Marchiori, Priscila; Ferreira, Vanessa C.; Fröner-Lacerda, Luana R. R.; Castro, Luiz Eduardo N.; Sillero Moreno, Leonor María; Zanin, Hudson G.; Forster Carneiro, Tania Biogas purification technologies facilitate the production of value-added products such as biomethane and industrial chemicals. This review was based on the assumption that biogas purification is underrepresented in the literature despite its significant potential for clean energy and greenhouse gas mitigation, warranting a comprehensive bibliometric and scientometric analysis. Using data from Clarivate Analytics’ ISI Web of Science, the study examines research on biogas purification and CO2 capture. The results show relatively few in-depth publications, but there is growing interest in biogas as a sustainable alternative to natural gas and conventional fuels, driven by emission reduction goals. Key challenges include high costs, limited technological advances (e.g., membranes, chemical absorption), and insufficient regulatory support. The leading areas of publication are energy fuels, environmental engineering, and environmental sciences. China, UK, and the USA are major contributors; however, the EU leads in commercial deployment, reflecting more advanced integration into sustainable energy systems. In addition to biogas, the fermentation process produces organic residues with significant potential for valorization through nutrient recovery, composting, and extraction of high-value products, enhancing resource efficiency and sustainability. Biogas represents a promising solution for energy transition, sustainable development, and circular economy integration. 2025-06-13T00:00:00Z http://hdl.handle.net/10498/39300 Potential biomethane productivity in the temperature phased anaerobic digestion process: Impact of organic load rate and solid retention time of acidogenic phase Díaz Domínguez, Encarnación; Ibáñez López, María Eugenia; Pérez García, Montserrat; Fernández-Morales, Francisco Jesús; García Morales, José Luis This study evaluated the biochemical methanogenic potential (BMP) of effluents from a thermophilic acidogenic anaerobic membrane bioreactor (AMBR) operated semi-continuously at different hydraulic retention times (HRT) and solids retention times (SRT). Thus, the influence of organic loading rate (OLR) and sludge age on mesophilic methane production was evaluated. In addition, two kinetic models (Gompertz and Cone) were proposed as tools for modelling methane production. An 18.7 % increase in OLR (from 4.48 to 5.32 gVS/L·d) in the acidogenic reactor results in a 9.4 % increase in effluent biodegradability, which enhances the methanogenic phase and increases methane production by 23.9 % in volume (from 271.05 to 335.84 mL CH4) and 42.8 % in yield (from 127.85 to 182.52 mL CH4/gVSadded). For an OLR of 4.48 gVS/L·d, extending the SRT from 6 to 12 days results in a 20.9 % increase in methane production volume (from 271.05 to 327.65 mL CH4) and a 14.9 % increase in yield (from 127.85 to 146.93 mL CH4/gVSadded). For an OLR of 5.32 gVS/L·d, extending the SRT from 4 to 8 days results in improved total solids (TS) and volatile solids (VS) removal, as well as a 20.9 % increase in methane production by volume (from 335.84 to 406.12 mL CH4). In both scenarios, extending the SRT leads to a longer lag time (λ) for methane production, with the Gompertz model fitting better than the Cone model. 2025-06-12T00:00:00Z