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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.

The influence of total solid contents during anaerobic mesophilic treatment of the organic fraction of municipal solid waste (MSW) has been studied in this work. The work was performed in batch reactors of 1.7L capacity, during a period of 85-95 days. Two different organic substrate concentrations were studied: 931.1 mgDOC/L (20% TS) and 1423.4 mgDOC/L (30% TS). Experimental results showed that the reactor with 20% total solids content had significantly higher performance. Thus, the startup phase ended at 14 days and the total DOC removal was 67.53%. The startup in reactor R30 ended at 28 days obtaining 49.18% DOC removal. Also, the initial substrate concentration contributed substantially to the amount of methane in the biogas. Hence, the total methane production in the methanogenic phase was 7.01 L and 5.53 L at the end of the experiments for R20 and R30, respectively.

In this work, we conducted a study that is to bleach wastewater model solutions loaded with dyes of indigo and sulfur black, while using and optimizing the process of hybridized treatment of textile effluents by torque of coagulation-ultrafiltration (CO-UF). According to the separate optimization of coagulation processes (optimum dose of the coagulant (lime) and ultrafiltration membrane (hydrodynamic characterization of the membrane based on polysulfone (PSU)), we combined the two methods in order to increase performance fading exploited colored waters. The results of the rate of discoloration separated by the methods of coagulation and ultrafiltration are respectively of the order of 33.55% and 80.36% for the water loaded with indigo and of the order of 25.33% and 60.78% for those charged with the black sulfur. While the results of the bleaching obtained by the hybrid method CO-UF have shown that the bleaching rate was calculated as around 98% for the indigo and of the order of 92% for the black sulfur, obviously very interesting with respect to the coagulation and ultrafiltration used separately. Moroccan Journal of Chemistry, Vol. 4, No 1 (2016)

The European Union is currently in the process of transformation toward a circular economy model in which different areas of activity should be integrated for more efficient management of raw materials and waste. The wastewater sector has a great potential in this regard and therefore is an important element of the transformation process to the circular economy model. The targets of the circular economy policy framework such as resource recovery are tightly connected with the wastewater treatment processes and sewage sludge management. With this in view, the present study aims to review existing indicators on resource recovery that can enable efficient monitoring of the sustainable and circular solutions implemented in the wastewater sector. Within the reviewed indicators, most of them were focused on technological aspects of resource recovery processes such as nutrient removal efficiency, sewage sludge processing methods and environmental aspects as the pollutant share in the sewage sludge or its ashes. Moreover, other wide-scope indicators such as the wastewater service coverage or the production of bio-based fertilizers and hydrochar within the wastewater sector were analyzed. The results were used for the development of recommendations for improving the resources recovery monitoring framework in the wastewater sector and a proposal of a circularity indicator for a wastewater treatment plant highlighting new challenges for further researches and wastewater professionals.

The inhibition of undesirable nitrite oxidizing bacteria (NOB) and desirable ammonium oxidizing bacteria (AOB) by free ammonia (FA) and free nitrous acid (FNA) in partial nitritation (PN) is crucially affected by the biomass growth mode (suspended sludge, biofilm, encapsulation). But, the limitations of these modes towards less concentrated reject waters (≤600 mg-N L-1) are unclear. Therefore, this work compares the start-up and stability of three PN sequencing batch reactors (SBRs) with biomass grown in one of the three modes: suspended sludge, biofilm and biomass encapsulated in polyvinyl alcohol (PVA) pellets. The SBRs were operated at 15°C with influent total ammonium nitrogen (TAN) concentrations of 75-600 mg-TAN L-1. PN start-up was twice as fast in the biofilm and encapsulated biomass SBRs than in the suspended sludge SBR. After start-up, PN in the biofilm and suspended sludge SBRs was stable at 150-600 mg-TAN L-1. But, at 75 mg-TAN L-1, full nitrification gradually developed. In the encapsulated biomass SBR, full nitrification occurred even at 600 mg-TAN L-1, showing that NOB in this set-up can adapt even to 4.3 mg-FA L-1 and 0.27 mg-FNA L-1. Thus, PN in the biofilm was best for the treatment of an influent containing 150-600 mg-TAN L-1.

CSP plant are facing the new challenge of being water thrifty because of their desert, hot and arid usual location. Actually, the water consumption of a CSP plant can reach around 2500 m3/GWh. Solutions have to be found to face the constraint of a reducing water availability in the concerned areas. Regarding the different water use items (power block's cooling : 90% of the total water use, solar field cleaning, up to 5% and steam generation), the WASCOP project is aiming at proposing different kind of solution in a holistic approach that will support the reduction of the water used by the whole plant without affecting its profitability. Regarding cooling, dry cooling is turning to zero the water use but the plant efficiency and profitability is significantly affected due to capacity limitations under high ambience and additional utilities costs. The solutions proposed in WASCOP are turned to increase the efficiency of the cooling systems under high ambience, through the addition of heat storage for delayed heat exhaust, the addition of water spray for enthalpic air refreshment of dry cooling systems and their increased efficiency and the optimized management of hybrized cooling system (wet/dry). For the cleaning needs of the plant, WASCOP proposes to develop different cleaning strategies. Firstly, limitation of the dust settlement on the optical surfaces is done through dust barriers and antisoiling coatings (both for reflectors and absorber's glasses). Secondly detection of the soiling level, for adapted cleaning frequencies at different locations within the solar field, is proposed thanks to different kind of soiling sensors : at low cost for a wide distribution, or with a capacity to discriminate soiling to mirror permanent degradation, or for specifically absorbers glasses. Thirdly, innovative cleaning devices using very few water, are proposed such as an ultrasonic cleaner, removing settled dust with a thin water layer thanks to cavitation properties, and a heliostat cleaner using the optical surface condensed water, and the rotating properties of the heliostat to remove dust with an adapted rotating cleaning lip. All the solutions developed in WASCOP are supported by numerical modelling as to be able to propose them within a single toolbox, selecting the most adapted solutions, depending on the plant technologies (type of solar field : PTC, LFR or ST and type of current cooling : WCC,ACC, Hybridized…) and locations (DNI, soiling rate…). Current results show that the proposed solutions are able to reduce the water use significantly both for cooling and cleaning purposes without affecting the plant global efficiency. Additional works have whatever to be done to better quantify the associated water reduction of individual solution and their synergy potentials.

The paper presents the comparative analysis of the amount of waste generated in Ukraine and European countries (except for radioactive waste) based on the official EU and Ukrainian statistical data. The data on waste generation are compiled according to the following classification: by economic activity and household, waste category, grades of hazard, and regions. In Ukraine, 352.3 million tons of waste was generated in 2018. By 2018, almost 13 billion tons of waste had been accumulated at the managed dumpsites, including about 12 million tons of hazardous and over 200 million tons of household waste. In the European Union, 2.6 billion tons of waste was generated in 2018. Over 70% of it was generated by 10 countries: Germany, France, England, Poland, Romania, Italy, Sweden, the Netherlands, Spain and Finland. By economic activity, the largest amounts of waste in Ukraine are generated by the mineral extraction and processing industry, the smallest – from water treatment and construction. In the EU countries, these values are somewhat different. For example, in Germany and France, the largest amounts of waste are generated from construction and manufacturing, the smallest – from agriculture, forestry and fishery. By waste category, the waste generated both in the EU countries and in Ukraine is mineral and solid waste. In Ukraine, the largest amounts of waste are produced and accumulated in the Dnipropetrovsk, Donetsk and Zaporizhzhia regions which accommodate large enterprises for extraction and mineral processing of iron and manganese ores, titanium-zirconium placers, coal, dolomite, and metallurgical limestone, as well as metallurgical and ferroalloy plants.

The steel industry is the largest consumer of energy in the world among industrial sectors. It is generally acknowledged that energy and environment are intimately related. Steel production is an energy intensive process that has a significant environmental impact. This paper reviews the progress made on energy consumption, carbon dioxide emissions and water consumption in the steel industry worldwide. The reduction in the availability of fresh water resources combined with the effects of global warming and climate change have increased pressure on industries, especially steel, to reduce its overall pollution, and specifically its water and carbon footprint. The implications of these effects on the value chain is discussed in this review. The contribution of new emerging technologies of iron and steelmaking is also reviewed. Finally, the important issues that contribute to define a sustainable industrial activity such as the recycling of steel and of by-products of steel production are studied. The history of steel industry is full of lessons, one of which is the need to keep the dreams alive. There are indeed expectations to solve problems created by technical progress.

Abstract In addition to CO2 released by the combustion of fossil fuel and leading to climate change, large steelworks emit pollutants that have other environmental impacts. ArcelorMittal Gent, an integrated steelwork producing ca. 5 × 106 tons of steel per year, not only decreased its specific energy consumption and CO2-emissions, but also reduced the environmental impact of its other emissions. This is illustrated by means of the evolution of 6 partial eco-efficiency indicators for the impact categories acidification, photo-oxidant formation, human toxicity, freshwater aquatic ecotoxicity, eutrophication and water use. The partial eco-efficiency indicators are eco-intensities, defined as the environmental impact in the respective impact category, divided by the amount of liquid steel produced. In the period 1995 – 2005 these indicators decreased by 45, 4, 52, 9, 11 and 33% respectively, whereas the steel production increased by 17%. The net impact of discharges of wastewater is negligible for human toxicity and is negative (concentrations lower than in the canal water used) for freshwater aquatic toxicity and eutrophication. For acidification, human toxicity (only emissions to air) and water use, the decoupling between environmental impact and production was absolute; for photo-oxidant formation, freshwater aquatic ecotoxicity (only emissions to air) and eutrophication, it was relative.