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Use of a pilot-scale fixed-film bioreactor was investigated for remediation of bromate contamination within groundwater. Bromate reduction with stoichiometric production of bromide was observed, providing supporting evidence for complete reduction of bromate with no production of stable intermediates. Reduction of 87-90% bromate from an influent concentration of 1.1 mg L(-1) was observed with retention times of 40-80 h. Lower retention times led to decreases in bromate reduction capability, with 11.5% removal at a 10 h retention time. Nitrate reduction of 76-99% from a 30.7 mg L(-1) as NO(3)(-) influent was observed at retention times of 10-80 h, although an increase in nitrite production to 2.7 mg L(-1) occurred with a 10 h retention time. Backwashing was not required, with the large plastic packing media able to accommodate biomass accumulation without decreases in operational efficiency. This study has provided proof of concept and demonstrated the potential of biological bromate reduction by fixed-film processes for remediation of a bromate contaminated groundwater source.

The phosphate (P) fertilizer industry generates a highly hazardous and acidic wastewater. The present study reports the evaluation of an integrated precipitation and Enhanced Biological Phosphorus Removal (EBPR) process for the treatment of fertilizer plant wastewater and effluent detoxification, assessed by microtoxicity and seed germination tests. Effluent samples were collected from a local P fertilizer industry and were characterized by their high fluoride and P content. First, the samples were pre‐treated by precipitation of P and fluoride ions using hydrated lime. The resulting low‐fluoride and phosphorus effluent was then treated with the EBPR process to monitor the simultaneous removal of carbon, nitrogen, and phosphorus. Phosphorus removal included a two‐stage anaerobic/aerobic system operating under continuous flow. Pre‐treated wastewater was added to the activated sludge and operated for 160 days in the reactor. The operating strategy included increasing the organic loading rate from 0.3 to 1.2 g chemical oxygen demand (COD)/L day. The stable and high removal rates of COD, NH4+‐N, and PO43−‐P were then recorded. The mean concentrations of the influent were approximately 3600 mg COD/L, 60 mg N/L and 14 mg P/L, which corresponded to removal efficiencies of approximately 98%, 86%, and 92%, respectively. The microtoxicity of the treated wastewater was then monitored by LUMIStox and its phytotoxicity was investigated on cress, tomato, wheat, maize, ryegrass, and alfalfa seed germination. LUMIStox tests showed that treatment allowed a significant toxicity removal. Moreover, the untreated wastewater inhibited the species germination even when diluted 10 times, whereas a positive effect of treated wastewater was noticed. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 463–471, 2014

Mercury (Hg) represents a growing environmental and health major concern. It originates from natural sources and mainly from anthropogenic processes and it is widely distributed in the natural media. According to the last Global Mercury Assessment (2013), annual global emissions from both sources were estimated to be from 5,000 to 8,000 metric tons per year. Among the different mercury species released to the environment, methylmercury (MeHg) is considered as the most toxic form due to its ability to bioaccumulate, being then threatening even at very low concentrations.Its presence depends onHg(II) bioavailability and global amount.This explains the urgent need to ensure a continuous Hg(II) monitoring. Many efforts have been made in order to develop reliable systems able to deliver quick data and to comply with low detection limits, in accordance with the threshold value delivered by the World Health Organization (1µg L-1/ 5 nM). Spectroscopic techniques such as CV-AFS and CV-AAS are routinely used for Hg(II) determination. Although these methods can afford good sensitivity and low concentrations determination, they require sample preparation step, complex procedures and expensive material, which limits their use for on-site measurements. In this context, electrochemical sensors present excellent candidates for in situ Hg(II) trace analysis, taking in account their numerous advantages compared to spectroscopic techniques: easier handling, simple procedure, low energy consuming, low cost material and portability. In this work, we will propose a new electrochemical approach aiming to conceive and optimize an electrochemical Hg(II) sensor. The method consists in the functionalization of a glassy carbon electrode (GC) with gold nanoparticles (AuNPs) and Diazonium Salts. The main idea is to combine the interesting properties of both AuNPs and Diazonium salts. AuNPs were chosen for their electrocatalytic effect, large surface area, mass transport enhancement and for the strong affinity to mercury which will improve the sensor sensitivity. On the other hand, diazonium salts are used to improve the sensor stability by anchoring the AuNPs to the GC surface. First, nanometricorganic layer were grafted of the polished GC surface, by electrochemical reduction of 1.5 mM4-thiophenol diazonium (SH) using Constant Potential Electrolysis (CPE) in 0.1 M HCl solution at -0.55 V for 300 seconds. Electrochemical characterization performed by Cyclic Voltammetry (CV) and redox probes (ferricyanide and hexaamineruthenium(III)) revealed a total suppression of the signal, confirming the formation of a continuous blocking layer. This was confirmed by Atomic Force Microscopy (AFM)used to estimate the layer thickness, which was found to be 4 nm. Second, AuNPs were electrodeposited, for the first time, onto the diazonium multilayer by CPE in NaNO3 solution containing 0.25 mM HAuCl4for 300 seconds. Once more, redox probes were used to characterize the resulting interface and a total signal restauration and enhancement was observed after AuNPs electrodeposition, which highlights the effective AuNPs onto the organic layers. Field emission gun scanning microscopy (FEG-SEM) was used to provided further evidence and to quantify particle size and density of the AuNPs deposits. Both size and density are dependent on the CPE duration. Small homogeneous AuNPs with 27±3 nm average diameter and 158 NPs/µm2density were observed when the CPE was carried out during 300 seconds, while larger particles with 63±6 nm average diameter and lower density (63 NPs/µm2) were obtained when a longer CPE duration (600 seconds) is used. Finally, AuNPs were activated by cyclic voltammetry in H2SO4 prior to Hg(II) detection in order to homogenize the surface and to rearrange the crystallographic plans of the AuNPs. Herein, the well-known gold oxides reduction peak was observed and used to calculate the electroactive surface area (ESA) of the functionlized electrode. The electrochemical response of the final generated GC/SH/AuNPs interface towards Hg(II) was recorded by Square Wave Anodic Stripping Voltammetry (SWASV) in 0.01 M HCl solution containing different amounts of Hg(II). The SWASV procedure consists on the Hg(II) preconcentration at the electrode surface followed by the preconcentrated Hg(0) reoxidation in Hg(II). Under optimized conditions, and for a preconcentration time of 300 seconds, a well-defined peak, corresponding to Hg(0) reoxidation, was observed around 0.5 V/ECS. The sensor showed a linearity range from 1 up to 10 nM and allowed to reach picomolar level. The stability in HCl, phosphate buffer and air was also studied over several weeks: Once a week, the activation procedure was performed and followed by Hg(II) determination in order to evaluate the analytical performances of the sensor over time. Finally, Hg(II) detection assays were conducted in natural water samples collected from different sampling points. Figure 1

<p>High temperature aquifer thermal energy storage (HT-ATES) can play a key role for a sustainable interplay between different energy sources and in the overall reduction of CO<sub>2</sub>emission. In this study, we numerically investigate the thermo-hydraulic processes of an HT-ATES in the Greater Geneva Basin (Switzerland). The main objective is to investigate how to handle the yearly excess of heat produced by a nearby waste-to-energy plant. We consider potential aquifers located in different stratigraphic units and design the model from available geological and geophysical data. Aquifer properties, flow conditions and well strategies are successively tested to evaluate their influence on the HT-ATES economic performance and environmental impact. This was achieved using a new open-access, user-friendly and efficient code that we also introduce here as a possible tool for geothermal applications.</p><p> </p><p>The results highlight the importance of thorough numerical simulations based on more realistic exploitation when designing HT-ATES systems. We show that relations between thermal performance and the shape of the injected thermal volume are generally hard to derive when complex well schedules are imposed because the injected/produced volumes may not be equal. Despite more complex storage strategies to comply with legal regulations, the shallower group of investigated aquifers in this study remains economically more suitable for storage up to 90ºC. In average four well doublets will be required to store the yearly excess of energy. The deeper group of investigated aquifers, however, become interesting for storage at higher temperatures.</p>

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 The mean squared slowing-down distance (Flux Age) and relaxation length have been measured in water using AmBe neutron source. With BF 3 -proportional detector the mean squared slowing-down distance was determined at cadmium resonance of 0.6 eV. The epithermal and thermal fluxes as a function of distance from source dipped in water were measured. The relaxation length for AmBe source is 10.8 ± 1.0 cm in water. The relaxation length was employed to extrapolate the observed data. The flux age comes to 58.5 ± 4.1 cm 2 . The effect of extrapolation of fast flux beyond measured values on flux age was also determined.

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.