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[EN]A systematic approach is developed for the conceptual optimal design of biomethane production via carbon capture. A hybrid heuristic-mathematical procedure is proposed to determine the optimal technology and operating conditions. The heuristic step consists of a literature-based screening of the available technologies. After the prescreening stage, the technologies selected are amine absorption, pressure swing adsorption (PSA), and membrane separation. The mathematical stage is composed of two steps. First, different alternatives for each technology are modeled based on first principles and rules of thumb. These models are used to select the optimal configuration for each process considered. Second, a superstructure model for biomethane production is developed integrating the pre-selected upgrading technologies to select the optimal process, as well as to determine the optimal operating conditions. Four waste sources are analyzed: cattle manure, swine manure, municipal food waste, and sludge. The results suggest that the best amine is diethanolamine (DEA), the best membrane material is the polyimide, and the suggested zeolite is 13X among the ones studied. Finally, among the three technologies, the overall results show that carbon capture using a PSA system using zeolite 13X results in lower production and investment costs, but very close to the use of membranes. The results indicate that food waste shows the lowest production cost for biomethane 0.36 €/Nm3, due to the largest organic matter content, whereas the investment costs are 67 M€, considering a biogas production rate of 0.035 kg of biomethane per kg of waste and the processing of 311 kt/yr of food waste. Credits or incentives are still needed for biomethane to be competitive with fossil natural gas. Junta de Castilla y León y USAL

Although recent research has demonstrated that waste orange peel (WOP) is a potentially valuable resource that can be transformed into high value products, heat generation, biomethanisation and composting might be considered the most feasible alternatives in terms of yield. This study revealed that WOP can be successfully valorised through combustion. However, a previous drying step, which generates hazardous wastewater, is required and harmful NOx are emitted with the flue gases. In contrast, a high yield of renewable methane (280LSTPCH4/kg added COD, chemical oxygen demand) and an organic amendment can be obtained through the thermophilic biomethanisation of WOP following the removal of valuable essential oils from the peel. Co-composting of WOP combined at different proportions (17-83%) with the organic fraction of municipal solid waste (OFMSW) was also demonstrated to be suitable. Moreover, a 37% reduction in odour generation was observed in co-composting of WOP compared to single composting of OFMSW.

In membrane bioreactors applied to wastewater treatment, fouling is typically a complex function of sludge characteristics. A pilot-scale tertiary submerged membrane bioreactor (tMBR) was continuously operated for over 200 days to assess the effect of biomass physiological state and environmental stress on process performance. Sludge characteristics were evaluated in terms of suspended solid concentration (MLSS and MLVSS), apparent viscosity, bioflocculation state, filterability, bioactivity, biopolymeric clusters (BPCs) and soluble microbial products. During the initial period of the tMBR start-up, when MLSS was below 3000 mg/L, the biomass was found to be very sensitive to environmental stress by sudden oxygen increase or organic shock loading, resulting in temporary biomass deflocculation and BPC release, and consequently, severe induced membrane fouling. However, at higher MLSS values, low stable biomass growth (0.04 ± 0.002 kg MLVSS/kg COD) was measured, regardless of organic overloading shocks or feeding failures. This period was also characterised by low bioactivity, BPC content and membrane fouling. Statistical analysis showed that BPCs have an important role when compared with other sludge properties as indicators of its fouling potential.

The global energy demand is growing substantially. Clean and secure energy supply is a must for our civilization's sustainable development. Solar and wind energy is growing fast and can contribute significantly to meet the goals set by many countries to reduce greenhouse gas emissions. A deep and wide investigation of the environmental impact of solar and wind energy is important before any solar or wind plants' construction is made. In this study, the literature is reviewed to summarize the environmental impact of solar and wind energy systems in terms of the following factors; land use, water consumption, impact on biodiversity, visual and noise effects, health issues, and impact on micro climate. Although the benefits of solar and wind energy are obvious and great, negative perception of these technologies can inhibit their wide penetration in some regions. This review paper includes a critical and an inclusive analysis of solar and wind energy’s environmental impact and may serve as an important tool to conduct a proper environmental impact assessment. This critical analysis may serve also as a tool for developers, policy, and decision-when planning future solar and wind farms.

La cuenca hidrográfica de Ikkour situada en la montaña del Atlas Medio (Marruecos) ha sido objeto de graves problemas de erosión del suelo. Este estudio tuvo como objetivo evaluar la susceptibilidad a la erosión del suelo en esta cuenca montañosa utilizando la Ecuación Universal de Pérdida de Suelos (USLE) e índices espectrales integrados con el entorno del Sistema de Información Geográfica (SIG). El modelo USLE requirió la integración de mapas de factores temáticos que son la agresividad de la lluvia, la longitud y la pendiente del talud, la cobertura vegetal, la erosionabilidad del suelo y las prácticas de control de la erosión. Estos factores se calcularon utilizando datos de teledetección y SIG. La evaluación basada en USLE mostró que la pérdida potencial de suelo anual total estimada fue de aproximadamente 70,66 toneladas ha-1 año-1. Esta pérdida de suelo se ve favorecida por las pendientes pronunciadas y la cubierta vegetal degradada. El método del índice espectral, que ofrece una evaluación cualitativa de la erosión hídrica, mostró diferentes grados de degradación del suelo en la cuenca del estudio según FI, BI, CI y NDVI. Los resultados de este estudio mostraron un acuerdo entre el modelo USLE y el enfoque del índice espectral, e indicaron que la tasa de erosión del suelo prevista puede deberse a la topografía más accidentada de la tierra y al aumento de las áreas agrícolas. De hecho, estos resultados pueden ayudar aún más a los responsables de la toma de decisiones en la implementación de un programa de protección adecuado para reducir la erosión del suelo. Le bassin versant d'Ikkour situé dans la montagne du Moyen Atlas (Maroc) a fait l'objet de graves problèmes d'érosion des sols. Cette étude visait à évaluer la sensibilité à l'érosion des sols dans ce bassin versant montagneux à l'aide de l'équation universelle de perte de sol (USLE) et d'indices spectraux intégrés à l'environnement du système d'information géographique (SIG). Le modèle USLE a nécessité l'intégration de cartes de facteurs thématiques qui sont l'agressivité des précipitations, la longueur et la pente de la pente, la couverture végétale, l'érodabilité des sols et les pratiques de contrôle de l'érosion. Ces facteurs ont été calculés à l'aide de données de télédétection et de SIG. L'évaluation basée sur l'USLE a montré que la perte potentielle totale annuelle estimée des sols était d'environ 70,66 tonnes ha−1 an−1. Cette perte de sol est favorisée par les pentes abruptes et la couverture végétale dégradée. La méthode de l'indice spectral, offrant une évaluation qualitative de l'érosion hydrique, a montré différents degrés de dégradation des sols dans le bassin versant d'étude selon FI, BI, CI et NDVI. Les résultats de cette étude ont montré un accord entre le modèle USLE et l'approche de l'indice spectral, et ont indiqué que le taux d'érosion du sol prédit peut être dû à la topographie des terres les plus accidentées et à une augmentation des zones agricoles. En effet, ces résultats peuvent aider davantage les décideurs à mettre en œuvre un programme de conservation approprié pour réduire l'érosion des sols. The Ikkour watershed located in the Middle Atlas Mountain (Morocco) has been a subject of serious soil erosion problems. This study aimed to assess the soil erosion susceptibility in this mountainous watershed using Universal Soil Loss Equation (USLE) and spectral indices integrated with Geographic Information System (GIS) environment. The USLE model required the integration of thematic factors' maps which are rainfall aggressiveness, length and steepness of the slope, vegetation cover, soil erodibility, and erosion control practices. These factors were calculated using remote sensing data and GIS. The USLE-based assessment showed that the estimated total annual potential soil loss was about 70.66 ton ha−1 year−1. This soil loss is favored by the steep slopes and degraded vegetation cover. The spectral index method, offering a qualitative evaluation of water erosion, showed different degrees of soil degradation in the study watershed according to FI, BI, CI, and NDVI. The results of this study displayed an agreement between the USLE model and spectral index approach, and indicated that the predicted soil erosion rate can be due to the most rugged land topography and an increase in agricultural areas. Indeed, these results can further assist the decision makers in implementation of suitable conservation program to reduce soil erosion. كان مستجمع مياه إيكور الواقع في جبل الأطلس الأوسط (المغرب) موضوعًا لمشاكل خطيرة تتعلق بتآكل التربة. تهدف هذه الدراسة إلى تقييم حساسية تآكل التربة في مستجمعات المياه الجبلية هذه باستخدام معادلة فقدان التربة العالمية (USLE) والمؤشرات الطيفية المتكاملة مع بيئة نظام المعلومات الجغرافية (GIS). يتطلب نموذج USLE تكامل خرائط العوامل المواضيعية وهي شدة هطول الأمطار، وطول المنحدر وانحداره، والغطاء النباتي، وقابلية تآكل التربة، وممارسات مكافحة التعرية. تم حساب هذه العوامل باستخدام بيانات الاستشعار عن بعد ونظم المعلومات الجغرافية. أظهر التقييم القائم على USLE أن إجمالي الخسارة السنوية المحتملة للتربة كان حوالي 70.66 طن هكتار-1 سنة-1. ويفضل فقدان التربة هذا المنحدرات الشديدة والغطاء النباتي المتدهور. أظهرت طريقة المؤشر الطيفي، التي تقدم تقييمًا نوعيًا للتآكل المائي، درجات مختلفة من تدهور التربة في مستجمعات المياه في الدراسة وفقًا لـ FI و BI و CI و NDVI. أظهرت نتائج هذه الدراسة وجود اتفاق بين نموذج USLE ونهج المؤشر الطيفي، وأشارت إلى أن معدل تآكل التربة المتوقع يمكن أن يكون بسبب تضاريس الأراضي الأكثر وعورة وزيادة في المناطق الزراعية. في الواقع، يمكن أن تساعد هذه النتائج صناع القرار بشكل أكبر في تنفيذ برنامج الحفظ المناسب للحد من تآكل التربة.

Abstract Pyrolysis is currently being considered as an alternative method of treating sewage sludge. It yields residual oils and gases, which can be used as fuels, and a solid which can either be burned or physically activated with air or CO 2 . The aim of this work was to study the influence of different pyrolysis conditions (e.g. temperature and heating rate) on the reactivity in air and in CO 2 of carbonaceous materials obtained from these types of residues. An anaerobic sewage sludge produced in a Spanish urban waste water treatment plant, containing 5 wt.% moisture after air-drying, was pyrolyzed in an electrical laboratory furnace under different pyrolysis conditions. Non-isothermal reactivities (up to 1100°C) in air and in CO 2 of the carbonaceous materials obtained after pyrolysis were performed in a thermobalance. The TG and DTG curves obtained from these experiments are discussed.

Chalcocite (Cu2S) has the fastest kinetics of dissolution of Cu in chlorinated media of all copper sulfide minerals. Chalcocite has been identified as having economic interest due to its abundance, although the water necessary for its dissolution is scarce in many regions. In this work, the replacement of fresh water by sea water or by reject brine with high chloride content from desalination plants is analyzed. Additionally, the effect of adding MnO2 from available manganese nodules in vast quantities at the bottom of the sea is studied. Reject brine shows better results than sea water, and the addition of MnO2 to the brine significantly increases the kinetics of chalcocite dissolution in a short time. H2SO4 concentration is found to be irrelevant when working at high concentrations of chloride and MnO2. The best results, 71% Cu extractions in 48 h, are obtained for reject brine, 100 mg of MnO2 per 200 g of mineral and H2SO4 0.5 mol/L. The results are expected to contribute to a sustainable process of dissolution of chalcocite by using the reject brine from desalination plants.

Anaerobic digestion is a commercial reality for several kinds of waste. Nonetheless, anaerobic digestion of single substrates presents some drawbacks linked to substrate characteristics. Anaerobic co-digestion, the simultaneous digestion of two or more substrates, is a feasible option to overcome the drawbacks of mono-digestion and to improve plants economic feasibility. At present, since 50% of the publication has been published in the last two years, anaerobic co-digestion can be considered the most relevant topic within anaerobic digestion research. The aim of this paper is to present a review of the achievements and perspectives of anaerobic co-digestion within the period 2010-2013, which represents a continuation of the previous review made by the authors [3]. In the present review, the publications have been classified as for the main substrate, i.e., animal manures, sewage sludge and biowaste. Animal manures stand as the most reported substrate, agro-industrial waste and the organic fraction of the municipal solid waste being the most reported co-substrate. Special emphasis has been made to the effect of the co-digestion over digestate quality, since land application seems to be the best option for digestate recycling. Traditionally, anaerobic co-digestion between sewage sludge and the organic fraction of the municipal solid waste has been the most reported co-digestion mixture. However, between 2010 and 2013 the publications dealing with fats, oils and greases and algae as sludge co-substrate have increased. This is because both co-substrates can be obtained at the same wastewater treatment plant. In contrast, biowaste as a main substrate has not been as studied as manures or sewage sludge. Finally, three interdisciplinary sections have been written for addressing novelty aspects in anaerobic co-digestion, i.e., pre-treatments, microbial dynamics and modeling. However, much effort needs to be done in these later aspects to better understand and predict anaerobic co-digestion.