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[Display omitted] • Anodic •OH role in cathodic electro-precipitation is investigated for the first time. • Anodic •OH reacts with CO 3 2– and decrease cathodic CaCO 3 electroprecipitation yield. • A new model is proposed to predict evolution of cathodic CaCO 3 electroprecipitation. Electrochemical systems are attracting increasing interest in environmental protection as relatively sustainable processes, particularly in wastewater treatment and reuse. However, cathode scaling in electrochemical processes for wastewater treatment is a major issue that is often overlooked. It is proposed for the first time to investigate the anodic contribution towards CaCO 3 electroprecipitation phenomena under the advanced electrooxidation conditions applied to remove organic biorecalcitrant pollutants. The contribution of the reaction of the hydroxyl radical (•OH) with carbonates, which reduces cathodic scaling at a micrometric interelectrode distance (500 µm) and at a high current density (16 mA cm−2), is described in detail. In addition, the anti-scaling effect of local anodic acidification should be considered. A new kinetic model of electroprecipitation fits the experimental curves well (root mean square error (RMSE) < 0.19 for Ca2+) and confirms this anodic role, combined with the gas hindrance and scale detachment induced by gas bubble electrogeneration at sufficiently high current intensities. [ABSTRACT FROM AUTHOR]

Bioethanol is expected to have a major contribution to transportation fuel consumption; hence, environmental analyses are crucial tools to evaluate its environmental performances. In this paper, a life cycle assessment is carried out to study the environmental performance of a bioethanol production system from Tunisian waste dates. The life cycle foreground data were derived from process simulation, while the background data were provided by the Ecoinvent 3.3 database. The impact assessment method applied is the ReCiPe midpoint (H). Seven environmental impact categories are discussed in detail in the interpretation section: global warming, acidification, eutrophication, agricultural land occupation, water depletion, cumulative energy, and cumulative exergy demands. The results indicate that 1 MJ of bioethanol produced from waste dates generates approximately 0.07 kg CO2-eq, which appears comparable with second-generation bioethanol production. One MJ of bioethanol requires approximately 1.087 MJ-eq of primary energy consumption of which 1.065 MJ is nonrenewable. The electric power generation process is the main contributor to most of the environmental impact categories (process hot spot). Therefore, it is strongly recommended to rely on renewable electricity generation to ensure relevant environmental improvements. [ABSTRACT FROM AUTHOR]

This study aims at contributing to the area of bio-based hydrogen production system development. A hydrogen production system via autothermal reforming of poultry fat was comprehensively investigated by life cycle assessment, after identification of the optimal thermodynamic operating conditions obtained via a detailed analysis of the involved chemical reactions. In the life cycle assessment, the system boundaries include reforming and rendering along with the required transportation processes. The rendering data are adapted from a literature review, whereas the reforming inventories data are derived from the process design and simulation of the entire hydrogen production process in Aspen Plus™ software. The life cycle inventories data for the hydrogen system are computationally implemented into SimaPro 7.3. Six relevant environmental impact categories are evaluated based on the CML baseline 2000. An energy analysis is also carried out based on cumulative energy demand and cumulative exergy demand as additional impacts categories. The life cycle assessment results are subjected to a systematic sensitivity analysis and compared to those achieved by other routes used for hydrogen production. The results show that poultry fat is a promising option for renewable hydrogen production considering the high productivity achievable with poultry fat (148.5 mol H 2 /kg of poultry fat); however, minimization of the heat requirement of the process is highly recommended to improve the system energetics and environmental performance. [ABSTRACT FROM AUTHOR]

This study investigated the chronic impact of sulfamethoxazole (SMX) on activated sludge sustaining an enriched nitrifying biomass. For this purpose, a laboratory scale fill and draw reactor was operated with 100 mg COD/L of peptone mixture and 50 mg N/L of ammonia at a sludge age of 15 days. Additionally, the biomass was exposed to a daily SMX dose of 50 mg/L once the reactor reached steady-state conditions. The reactor performance and microbial composition were monitored for 37 days with conventional parameters and molecular techniques based on the gene for ammonia monooxygenase subunit A ( amoA ) and the prokaryotic 16S rRNA gene. Denaturing gradient gel electrophoresis (DGGE) and 16S rRNA gene cloning analyses suggested a microbial community change concurrent with the addition of SMX. Specifically, quantitative polymerase chain reaction analyses (qPCR/RT-qPCR) revealed a significant reduction in the levels and activity of ammonia oxidizing bacteria (AOB). However, the acclimation period ended with high amoA mRNA levels and improved nitrification efficiency. Partial degradation of SMX by heterotrophic bacteria was also observed. [ABSTRACT FROM AUTHOR]

This study evaluated the chronic impact of tetracycline on biomass with enriched nitrifying community sustained in a lab-scale activated sludge system. For this purpose, a fill and draw reactor fed with 100 mg COD/L of peptone mixture and 50 mg N/L of ammonia was sustained at a sludge age of 15 days. At steady-state, the reactor operation was continued with a daily tetracycline dosing of 50 mg/L for more than 40 days, with periodic monitoring of the microbial composition, the nitrifying bacteria abundance, as well as the amoA and 16S rRNA gene activity, using molecular techniques. Changes in the kinetics of nitrification were quantified by modelling concentration profiles of major nitrogen fractions and oxygen uptake rate profiles derived from parallel batch experiments. Activated sludge modeling results indicated inhibitory impact of tetracycline on the growth of nitrifiers with a significant increase of the half saturation coefficients in corresponding rate equations. Tetracycline also inactivated biomass components of the enriched culture at a gradually increasing rate with time of exposure, leading to total collapse of nitrification. Molecular analyses revealed significant changes in the composition of the microbial community throughout the observation period. They also showed that continuous exposure to tetracycline inflicted significant reduction in amoA mRNA and 16S rRNA levels directly affecting nitrification. The chronic impact was much more pronounced on the ammonia oxidizing bacteria (AOB) community. These observations explained the basis of numerical changes identified in the growth kinetics of nitrifiers under stress conditions. [ABSTRACT FROM AUTHOR]

Chromium has two main oxidation states, Cr(III) and Cr(VI), that can occur simultaneously in natural waters. Current consensus holds that Cr(VI) is of high ecotoxicological concern, but regards Cr(III) as poorly bioavailable and relatively non-toxic. In this work, the effects and bioaccumulation of Cr(III), Cr(VI) and their mixture were studied using the freshwater clam Corbicula fluminea as a model organism. Mixture exposures were carried out using solutions isotopically enriched in 50Cr(III) or 53Cr(VI), allowing to quantify the contribution of each redox form to total Cr accumulation in the clams. Following exposure to individual redox forms, Cr(III) accumulated preferentially in the digestive glands and Cr(VI) in the gills of C. fluminea. In mixture exposures, both redox forms accumulated mainly in the gills; the concentration of Cr(III) in the digestive glands being much lowered compared with individual exposures. Both oxidation states affected the expression of biomarkers related to energy reserves, cellular damage and mitochondrial functioning, as well as the expression of mRNA for detoxification genes. The observed effects differed between gills and digestive glands. The present study suggests that Cr(III) is a bioavailable and biologically active elemental species deserving more consideration by the ecotoxicological community. [Display omitted] • Biomarkers expression responds to Cr redox state, concentration and exposure duration. • First use of isotopically enriched solutions to study Cr(III)/Cr(VI) mixtures. • Both Cr(VI) and Cr(III) accumulate in gills and digestive glands of Corbicula fluminea. • The presence of Cr(VI) changes the accumulation pattern of Cr(III). • Cr(III) is a biologically active species along with Cr(VI). [ABSTRACT FROM AUTHOR]

In this work, various assessment tools were comprehensively applied to investigate hydrogen production via glycerol autothermal reforming. These tools are used to study the chemical reactions, design and simulate the entire hydrogen production process, investigate the energetic and exergetic performances of the processes and perform parametric analyses (using intuitive and design of experiment-based methods). Investigating the chemical reactions of autothermal reforming (ATR) of glycerol reveals that the optimal conditions, based on maximizing the hydrogen production, minimizing the methane and carbon monoxide contents and eliminating coke formation at thermoneutral conditions, can be achieved at a water–glycerol feed ratio (WGFR), reforming temperature ( T ) and oxygen–glycerol feed ratio (OGFR) of 9, 900 K and 0.35, respectively. The energetic study of the resulting process indicates that approximately two-thirds of the energy fed to the process is recovered in the useful product (H 2 ) and that the remaining incoming process energy is exhausted in the off-gas. The exergetic investigation reveals that the exergetic efficiency of the ATR process is 57% and that 152 kJ are destroyed to generate 1 mol of hydrogen. The process operating conditions recommended by the chemical reaction investigation suffers from low performance because energetic and exergetic efficiencies are comparatively lower than values previously reported in literature for other reformates. The parametric investigation indicates that more accurate conditions are needed to convert glycerol–hydrogen. These conditions ensure the lowest consumption of energy to generate a given amount of hydrogen. This paper recommends WGFR = 5.5, T = 900 K and OGFR = 0.96 as the optimum conditions for the entire glycerol-to-hydrogen process. For this configuration, the thermal and exergetic efficiencies are 78.7% and 67.8%, respectively. [ABSTRACT FROM AUTHOR]

In this study, the adsorption and photocatalytic degradation of isoproturon (one of the most widely used herbicides in agriculture) was investigated in an annular photoreactor packed with a TiO2 photocatalyst. The results highlighted that the monolayer Langmuir adsorption isotherm model was well obeyed. The isoproturon adsorption equilibrium constant was determined experimentally. The codegradation of isoproturon and of other copollutants such as salicylic acid and phenol occurred, demonstrating that within the catalyst, the same type of sites can be involved in the adsorption of the two pollutants. The heat of adsorption fell in the range of 20 to 50 °C and was found to be ~43 kJ/mol. As expected, the adsorption constant Ka decreased with increasing the fluid flow due to the temperature rise. The kinetics of the photocatalytic degradation of isoproturon revealed a first-order reaction for initial concentrations between 3 and 43 ppm. In our experimental conditions, no by-products were detected and total disappearance of isoproturon was observed. [ABSTRACT FROM AUTHOR]

[Display omitted] • New mechanisms of mineral scaling on cathode at various interelectrode distances. • New model on Mg(OH) 2 and CaCO 3 depositions at various interelectrode gap. • Crucial roles of cathode potential, H 2 and O 2 gas evolutions on mineral scaling. • A decrease of internal ohmic resistance did not imply a reduction of mineral scaling. • Modeling of charge transfer resistance and double-layer capacitance at interface. For the first time, the roles of submillimetric interelectrode distances (d elec) and electrogenerated gas on cathodic mineral electro-precipitation have been investigated, particularly under advanced electro-oxidation condition with boron-doped diamond (BDD) anode. The main objective was to understand how to limit or favor the magnesium hydroxide (Mg(OH) 2) and calcium carbonate (CaCO 3) deposits that progressively passivate the cathode surface during the electrolysis of effluent initially containing calcium (Ca2+), magnesium (Mg2+) and bicarbonate/carbonate (HCO 3 –/CO 3 2–). As predicted by a new model taking into account the concomitant H 2 evolution reaction (HER), more mineral scaling (Mg(OH) 2 and CaCO 3) was observed in decreasing order of d elec from 3 mm to 100 μm at 4 mA cm−2. Contrastingly, no deposit was present at the lowest d elec (50 μm), which was due to non-faradaic condition. The applied cathode potential (E C) decreased with increase of d elec , which intensified the H 2 gas bubbles production and minimized the electro-precipitation. Supplementary experiments with identical E C highlighted the additional involvement of O 2 evolution at the anode towards the cathodic mineral scaling, whose role was intensified at submillimetric distances. Finally, novel predictive correlations have been proposed from impedance spectroscopy studies at cathode/electrolyte interface in order to link the charge transfer resistance (R CT) and the double-layer capacitance (C DL) with d elec. [ABSTRACT FROM AUTHOR]

Abstract: Three known types of ethanol reforming processes, ethanol steam reforming (ESR), partial oxidation (POX) and auto-thermal reforming (ATR), are investigated. Favorable operating conditions are identified for each reaction system to maximize the production of hydrogen from bioethanol. Each process consists of three sections: the main reactor (ESR, POX or ATR), the CO clean-up section comprised of the water gas shift reactor and preferential CO oxidation reactor and finally, the purification section. The performances of these processes are evaluated through mass, energy and exergy analyses. The material balances show that the total amount of ethanol required to generate 1mol of hydrogen is 0.23mol for the ATR, 0.24mol for the POX and 0.25mol for the ESR. The ATR reforming process is shown to have the highest energetic efficiency, i.e., the lowest amount of energy is consumed to produce the same amount of hydrogen from ethanol. Moreover, the ATR process has the best exergetic performance, as it presents the highest ratio of exergy recovered in the hydrogen stream to the total exergy supplied to the system. For all three of the systems, the exergy destruction occurs mainly in the reformer due to the high irreversibility of the reaction. [Copyright &y& Elsevier]

Abstract: Cadmium uptake by activated sludge was studied following modifications of sludge composition and surface properties induced by ozone treatment. Ozone leads to the solubilization of sludge compounds as well as their mineralization, especially humic like substances. Small particles were formed following floc disintegration, leading to a decrease of average floc size. The study of surface properties underlined the mineralization as the number of surface binding sites decreased with the increase of ozone dose. Depending on ozone dose, cadmium uptake by activated sludge flocs was either increased or decreased. Different mechanisms were involved: below 10mgO3/gTS, the increase of floc specific surface area following floc size decrease as well as the release of phosphate ions yielded an increase by 75% of cadmium uptake, due to the better availability of biosorption sites and the increase of precipitation. Inversely, at higher ozone doses, the number of biosorption sites decreased due to oxidation by ozone. Moreover, dissolved organic matter concentration increased and provided ligands for metal complexation. Cadmium uptake was therefore limited for ozone doses ranging from 10 to 16.8mgO3/gTS. [Copyright &y& Elsevier]

The aim of this study was to assess the potential of the woody nickel hyperaccumulator species Blepharidium guatemalense (Standl.) Standl. for agromining in southeastern Mexico. Pot trials consisting of nickel dosing (0, 20, 50, 100, and 250 mg Ni kg−1), and synthetic and organic fertilization were conducted. Field trials were also undertaken with different harvesting regimes of B. guatemalense. Foliar nickel concentrations increased significantly with rising nickel additions, with a 300-fold increase at 250 mg Ni kg−1 treatment relative to the control. Synthetic fertilization strongly increased nickel uptake without any change in plant growth or biomass, whereas organic fertilization enhanced plant shoot biomass with a negligible effect on foliar nickel concentrations. A 5-year-old stand which was subsequently harvested twice per year produced the maximum nickel yield tree−1 yr−1, with an estimated total nickel yield of 142 kg ha−1 yr−1. Blepharidium guatemalense is a prime candidate for nickel agromining on account of its high foliar Ni concentrations, high bioconcentration (180) and translocation factors (3.3), fast growth rate and high shoot biomass production. Future studies are needed to test the outcomes of the pot trials in the field. Extensive geochemical studies are needed to identify potential viable agromining locations. Novelty Statement Our research team is a pioneer in the discovery of metal hyperaccumulator plants in Mesoamerica with at least 13 species discovered in the last 2 years. This study is the first to assess the potential of nickel agromining (phytomining) in Mexico (and in all the American continent), using one of the strongest nickel hyperaccumulators reported so far. The promising results of this study are the basis for optimal agricultural management of Blepharidium guatemalense. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Minor pollutants emitted during wood combustion play an important role in the GWP. • A low GWP bio impact factor is required for bioenergy scenarios to be competitive. • Local, forest-specific assessment are necessary before encouraging wood use to grow. Abstract In this work wood-to-heat chains are assessed on environmental and micro-economical aspects. Wood combustion produced various minor pollutants, which should be considered in life cycle assessment. For this purpose different wood combustion processes have been modeled under Aspen Plus® software in order to assess pollutant emissions (CO 2 , aromatic compounds, CO, etc.) based on industrial emission data and therefore to obtain a rigorous life cycle inventory. Different technologies are assessed for a fixed heating demand and hot water production of a typical French house: district heating fueled by wood chips, individual stoves or boilers fueled by wood logs or pellets. Electricity, natural gas, and fuel oil solutions complete the scenario set. The different heating solutions are compared in terms of their greenhouse gas emissions and of the cost of the final energy (including investment and operating costs). The important effect of minor pollutants (such as CO and volatile organic compounds) on the global warming potential of wood-to-heat chains is highlighted. The performance of wood scenarios compared to fossil-based ones is also highly dependent on the impact factor assumed for the biogenic CO 2. The wood-based scenarios present a wide range of costs with pellet solutions being more expensive on investment and pellet production. [ABSTRACT FROM AUTHOR]

The main purpose of this study is to comprehensively investigate a biodiesel production system by transesterification of mutton tallow. To this end, an exergo-environmental life cycle assessment was applied. Exergetic investigation identifies the location, magnitude and sources of the thermodynamic inefficiencies in the biodiesel production process (the highest priority components for process improvement from the thermodynamic point of view). In contrast, environmental life cycle assessment identifies the environmental hot spot subsystems of the entire mutton tallow-to-biodiesel system (the highest priority life cycle steps for environmental improvement). The results obtained show that approximately 83.3% of the exergy fed to the process is recovered in the useful product (biodiesel). The transesterification reactor should have the highest priority for process improvement from the thermodynamic point of view. However, the environmental improvements of the entire biodiesel production system should be focused on minimizing methanol consumption. The net energy ratio of the system is approximately 2.3. Therefore, the biodiesel system presents a net energy gain. Using economic allocation instead of the mass-based approach leads to an increase in the life cycle indicators by approximately 11%. However, this difference is only 6.7% when considering energy allocation. [ABSTRACT FROM AUTHOR]

Being an internationally accepted standard for the activated sludge modeling, the Activated Sludge Model No.1 (ASM1) was used to simulate the treatment of paper mills effluent in an industrial full-scale sequencing batch reactor (SBR). Key characteristic parameters were estimated and corrected with the wastewater temperature: maximum heterotrophic growth rate μ H (9.69/day), heterotrophic yield Y H (0.625 g cell COD/g COD oxidized) and heterotrophic decay rate b H (1.98/day). The wastewater chemical oxygen demand (COD) was fractionated as slowly biodegradable substrate X S (20%), particulate inert organic matter X I (58%), readily biodegradable substrate S S (18%) and soluble inert organic matter S I (4%). Finally, the SBR operation was simulated with field data from the paper mill. The average relative error of the simulated effluent COD was 12.7%. The results showed that the ASM1 could be reasonably used in the papermaking wastewater treatment simulation. [ABSTRACT FROM AUTHOR]

The photocatalytic degradation of an antibiotic (spiramycin) has been studied using immobilized titanium dioxide (TiO 2 ) as a photocatalyst in a laboratory reactor under ultraviolet illumination (365 nm). The degradation of the antibiotic was monitored by ultraviolet spectrophotometry and high-pressure liquid chromatography and confirmed by an antibacterial activity evaluation. Two types of TiO 2 (P25 and PC500) immobilized on glass plates were compared. For TiO 2 PC500 immobilization on glass and paper was also studied. A slightly better degradation was obtained with TiO 2 P25 for which the degradation kinetics were investigated. The Langmuir–Hinshelwood kinetic model is satisfactorily obeyed at initial time and in the course of the reaction. Adsorption and apparent rate constants were determined. These results show a complete degradation of spiramycin, which was confirmed by the inhibition of the antibacterial activity of Staphylococcus xylosus , when exposed to spiramycin solutions treated with photocatalyst for a short time. In addition, the codegradation of spiramycin and tylosin was investigated and showed that tylosin had a higher affinity to the catalyst TiO 2 P25 than spiramycin. The complete degradation of spiramycin confirms the feasibility of such a photocatalytic treatment process for spiramycin elimination from contaminated water. [ABSTRACT FROM AUTHOR]

Agromining is the recovery of valuable heavy metals from soils with high metal concentrations, using hyperaccumulator plants, to produce value added products. It allows the exploitation of low-grade ores for which conventional mining techniques are too expensive and detrimental to the environment. It is also a means for the restoration of closed mines and heavy metal contaminated soils. On lands of low fertility and high concentration in metals, e.g. serpentine soils in the Balkans, it can provide income sources for the local farmers and improve soil fertility and resistance to erosion. We presented here the Life Cycle Assessment of an agromining supply chain. This chain included i) the recovery of nickel from serpentine soils in the Balkans with cropped hyperaccumulator Alyssum murale, and ii) the production of ammonium nickel sulfate hexahydrate (ANSH) from the resulting ashes using hydrometallurgical processes. Results showed that if not controlled by anti-erosion practices, soil loss at farm scale is responsible for significant impacts, especially on human and environmental health, due to the high heavy metal content of soil particles. However, agromining has a similar impact as normal agricultural practices implemented on the territory. It may be used as cover crop instead of leaving bare soils. Its impact would therefore be beneficial. Heat recovery from biomass combustion avoids significant impact, depending on the energy source it may replace. Proper combustion fume filtration and fly ash recovery reduce risks on human health and maximize metal recovery. Byproducts derived from the process may return to the field to compensate nutrient uptake by crops and improve soil fertility. In conclusion, LCA demonstrated that the whole agromining chain offers the opportunity to promote new agricultural practices and preserve valuable resources. Improvements of the industrial processes are however necessary to increase Ni recovery, purity and added value of final products. [ABSTRACT FROM AUTHOR]

Abstract: The challenges in reducing the world's dependence on crude oil and the greenhouse gas accumulation in the atmosphere, while simultaneously improving engine performance through better fuel efficiency and reduced exhaust emissions, have led to the emergence of new fuels, with formulations blending petrodiesel, biodiesel, bioethanol and water in various proportions. In parallel, the sustainability of the new biofuel industries also requires to maintain a high level of biodiversity while playing on techno-diversity, using a variety of resources that do not compete with edible crops (nor by using arable land for energy crops or food crops for energy production) and flexible conversion technologies satisfying the eco-design, eco-energy and eco-materials criteria. In addition, it would be relevant to consider blending ethyl biodiesel, instead of methyl biodiesel, with petrodiesel, particularly if the fuel formulation is completed with bioethanol (or even water). The supercritical ethanolysis of lipid resources to produce ethyl biodiesel is a simple but efficient route that should have the potential to satisfy the sustainability criteria if analyzed holistically. Therefore, this review focuses specifically on the production of ethyl biodiesel via triglyceride supercritical ethanolysis within a global analysis “feedstocks-conversion-engine”. The scientific and technical bottlenecks requiring further development are highlighted by emphasizing (i) the kinetic and thermodynamic aspects (experiments and modeling) required for the process simulation, the results of which aim at securing the life cycle assessment, first at the process level and then at the fuel level; (ii) the proposals to improve the supercritical process performance in terms of eco-material and eco-energy; (iii) the impacts of ethyl vs. methyl biodiesel fuels and of biodiesel–ethanol–petrodiesel blends (with or without water) on the diesel engine emissions and performance; (iv) the technological flexibility of the supercritical process allowing its conversion toward production of other key products. Finally, built on the state-of-the art review, a new R&D direction combining supercritical ethanolysis of lipids with the addition of CO2, glycerol recovery, and cogeneration, according to the biorefinery concept, is proposed and discussed. [Copyright &y& Elsevier]

Abstract: Various assessment tools are applied to comprehensively investigate a glycerol-to-hydrogen production system. These tools investigate the chemical reactions, design and simulate the entire hydrogen production process, study the energetic and exergetic performances and perform parametric analyses (using intuitive and design of experiment-based methods). Investigating the chemical reaction of steam glycerol reforming reveals that the optimal conditions, determined based on maximizing the hydrogen production while minimizing the methane and carbon monoxide contents and coke formation, can be achieved at a reforming temperature and a water-to-glycerol feed ratio (WGFR) of 950 K and 9, respectively. The thermal and exergetic efficiencies of the resulting process are 66.6% and 59.9%, respectively. These findings are lower than those cited in the literature and relative to other reformates (methane, ethanol and methanol). The parametric investigation indicates that the performance of the process (energetic and exergetic) could be ensured by using an appropriate and judiciously selected combination of the reactor temperature and WGFR. Based on the parametric energetic and exergetic investigation, WGFR = 6 and T = 1100 K appear to be the most accurate parameters for the entire glycerol-to-hydrogen process. For this recommend configuration, the thermal and exergetic efficiencies are 78.1% and 66.1%, respectively. [Copyright &y& Elsevier]

Abstract: The effect of surface topography on the long-term development (≈10 weeks) of biofilms has been investigated using a monitoring technique based on images produced by a flat-bed scanner and initially developed for flat surfaces. The biofilm response to rotation speed changes in lab-scale rotating biological contactors (RBCs) has been studied. Two RBCs, each containing five discs (two with flat surfaces and three with rough surfaces) were run initially at two different rotation speeds: 4rpm for reactor I and 40rpm for reactor II. After 47 days, the rotation speed was increased in reactor I to 40rpm and decreased in reactor II to 4rpm. Prior to the rotation speed change, the biofilm on the flat discs underwent large detachments in both reactors, but the biofilm on rough discs was less extensively damaged. The increase in rotation speed induced large detachments of the biofilm in reactor I on all discs, but the biofilm on the rough discs recovered more effectively with faster regrowth. In reactor II, the decrease in rotation speed favored the development of the biofilm. Wall stress distributions obtained from CFD simulations on flat and rough discs at different rotation speeds were well correlated with experimental observations. [Copyright &y& Elsevier]

Abstract: The tertiary treatment of paper mill wastewaters was investigated by testing the effect of batch electrocoagulation for 90min with two parallel iron or aluminum plates at two values of the current density (100 and 150A/m2). Dissolved organic carbon removal ranged between 24% and 46%, and chemical oxygen demand removal ranged between 32% and 68%. UV–visible spectroscopy showed a reduction of the aromaticity of the treated effluent. The process was also very efficient for the removal of lignin-based pollution, characterized by the fluorescence of humic substances. Arsenic was selected as an example of a non-organic micropollutant and was also satisfactorily removed (from 4 to 0.5μg/L). The settling characteristics of the sludge obtained after the electrocoagulation treatment were also evaluated. The sludge aptitude to settling is better with Fe electrodes than with Al electrodes. The experimental results obtained in the present study indicate that electrocoagulation treatment can be very effective and was capable of improving the paper mill wastewaters’ quality downstream of the biological treatment. [Copyright &y& Elsevier]

Abstract: Photocatalysis, based on UV irradiation of a TiO2 support to generate oxygen free radicals, has been shown to have antibacterial properties, but the process has yet to be optimized. Photocatalytic inactivation of Gram negative bacteria, E. coli, was studied on five different photocatalytic supports, in terms of TiO2 type (Degussa P25/Millennium PC500) and configurations (catalyst was impregnated on supports, alone or with binder, or suspended in water). Several irradiation times were tested. Effective UV-A doses were estimated using a simulation based on a Monte Carlo approach to facilitate comparison between supports. For the same TiO2 type, inactivation efficiency was best with the “suspension” configuration (up to 4 log in 120min) followed by the “impregnated without binder” configuration (up to 2 log in 120min) and finally the configuration with binder (only 0.5 log after 120min). In the “suspension” configuration, TiO2 P25 appeared to be more effective than TiO2 PC500. This may be due to smaller dispersed particle sizes. Our experiments highlight the importance of optimizing contact between the bacteria to be inactivated and titanium dioxide particles. Bacterial regrowth was compared on two culture media with different nutrients, and revealed metabolic damage induced by photocatalysis. Based on the classical Chick–Watson model, the kinetics of the photocatalytic process were determined, including a lag time for several supports. [Copyright &y& Elsevier]

Abstract: This study investigates erythromycin toxicity toward activated sludge as a function of exposure time and antibiotic concentration. Batch experiments were conducted and microscopic techniques ranging from bright-field microscopy to epifluorescence and confocal laser scanning microscopy (CLSM), combined with a fluorescent viability indicator (BacLight ® Bacterial Viability Kit, Molecular Probes), allowed us to study erythromycin time-kill activity. The erythromycin toxicity was observed at lower concentration when exposure time increased. A 4μg/L erythromycin concentration was toxic to heterotrophic bacteria on a 5-day time exposure, and a 5mg/L concentration inhibited nitrification. These findings are in agreement with the microscopic studies, which showed a latency time before the lower antibiotic concentrations began to kill bacteria. Microscope slide wells were used as micro-reactors in which erythromycin concentration ranged from 0.1 to 1mg/L. After 45min there were 94% (SD 3.8) of living bacteria in control micro-reactors, 67% (SD 3.1) in micro-reactors that contained 0.1mg/L erythromycin and 37% (SD 18.6) in micro-reactors that contained 1mg/L erythromycin. CLSM allowed visualization of isolated stained cells in the three-dimensional structure of damaged flocs. [ABSTRACT FROM AUTHOR]

Abstract: Hydrogen is expected to play a significant role in future energy systems. The efficient production of hydrogen at a minimum cost and in an environmentally acceptable manner is crucial for the development of a hydrogen-including economy. The exergy analysis is a powerful tool to quantify sustainable development potential. An important aspect of sustainable development is minimizing irreversibility. The purpose of this study is to perform the exergy analysis of a steam methane reforming (SMR) process for hydrogen production. As a first step, an exergy analysis of an existing process is shown to be an efficient tool to critically examine the process energy use and to test for possible savings in primary energy consumption. The results of this investigation prove that the exergetic efficiency of the SMR process is 65.47%, and the majority of destroyed exergy is localized in the reformer with a 65.81% contribution to the whole process destroyed exergy. Next, an exergetic parametric study of the SMR has been carried out with a factorial design of experiment (DOE) method. The influence of the reformer operating temperature and pressure and of the steam to carbon ratio (S/C) on the process exergetic efficiency has been studied. A second-order polynomial mathematical model has been obtained through correlating the exergetic efficiencies with the reformer operating parameters. The results of this study show that the rational choice of these parameters can improve the process exergetic performance. [Copyright &y& Elsevier]

The solid waste of olive oil extraction processes (olive pomace, OP) was converted into activated carbon (AC) by treating it with NaOH and then encapsulating it within sodium alginate (SA) in beads by crosslinking (SA-AC beads). The prepared SA-AC beads were utilized as an adsorbent for the elimination and recovery of phenolic compounds (PCs) from olive mill wastewater (OMWW) following a zero liquid and waste discharge approach to implement and promote the circular economy concept. The novel AC and SA-AC beads were characterized by scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) and Brunauer, Emmett and Teller (BET) analysis. The adsorption performance of these beads was evaluated in batch and fixed-bed reactors operated in a concurrent flow system. The results revealed that an adsorption capacity of 68 mg g−1 was attained for 4000 mg L−1 phenolic compounds. The kinetics of the adsorption process of the PCs fit a pseudo second-order model, and the most likely mechanism took place in two stages. The adsorption isotherm conformed to the Langmuir model, representing the monolayer adsorption of the phenolic compounds. The dynamic models were used, and they accurately represented the breakthrough curves. Considering PC recovery and process reusability, a regeneration experiment of SA-AC beads was carried out in fixed-bed reactors. SA-AC beads showed a high percentage desorption >40% using ethanol and were efficient after several cycles of OMWW treatment and phenol recovery. [Display omitted] • Porous beads based on activated carbon from olive pomace was prepared. • The removal efficiency of phenolic compounds using beads improved significantly. • The adsorption kinetics, isotherms and thermodynamic were studied. • Breakthrough curves from fixed-bed adsorption columns were evaluated and modeled. • 40% recovery of phenolic compounds using ethanol was achieved. [ABSTRACT FROM AUTHOR]

• Local cathodic alkalization occurs predominantly due to H 2 O reduction not O 2. • Electromigration does not influence electro-precipitation within the conditions. • Mg(OH) 2 electro-precipitation depends only on applied current density. • Gas evolution and Mg2+ ion decrease CaCO 3 electro-precipitation. • Models to predict electro-precipitation in thin-film cell have been proposed. It is presented for the first time the occurrence and modelling of cathodic mineral electro-precipitation in microfluidic thin-film configuration of electrochemical advanced oxidation process (EAOP), in order to better understand and predict the cathode's scaling when treating water containing Mg2+ and Ca2+. Upon a systematic study, the main results show that when an inter-electrode distance of 500 µm is used at 4 mA cm−2, local alkalization on cathode surface occurs despite the absence of dissolved O 2 suggesting that it takes place due predominantly to water reduction (current efficiency > 99%) and not dissolved O 2 reduction. Moreover, electromigration phenomenon could be neglected when varying ionic strength from 0.02 to 0.1 mol L−1, while diffusion was the kinetic rate-limiting step. In addition, Ca(OH) 2 and MgCO 3 precipitates were not formed under all investigated conditions. Mg(OH) 2 electro-precipitation was found to be highly dependent on current density, but independent of other ionic species jointly present in electrolyte. Mg(OH) 2 precipitated once interfacial pH of 10.2 was reached. More CaCO 3 was electro-precipitated at lower current density (ca. 7.2%) owing to more vigorous gas evolution when higher current density was applied. 12% less CaCO 3 electro-precipitation was found in the presence of Mg2+ confirming its inhibiting effect towards CaCO 3 scaling. The mathematical model proposed could fit well the experimental curves (Root mean square error (RMSE) < 0.1163) and permit to predict the evolution of concentration of depositing species (i.e. Mg2+, Ca2+ and CO 3 2−). Furthermore, the role of hydroxyl radicals (•OH) produced at boron-doped diamond (BDD) anode could be neglected upon the applied conditions, meaning that the outcome of this study is reliable across all types of water containing Mg2+, Ca2+ and/or CO 3 2− in compliance to their ubiquity when it is to be treated by electrolysis in general. [ABSTRACT FROM AUTHOR]

Anthropogenic activities linked to various new technologies are increasingly disrupting REEs biogeochemical cycles. A catchment-based perspective is therefore necessary to distinguish between natural (i.e., changes in lithology) and human-related sources of REEs variability. In the present study, REEs patterns, anomalies and fluxes were investigated in the French part of the Moselle River basin (Moselle River itself and some of its headstreams and tributaries). The REEs patterns in the headstream waters were highly variable and mostly related to the complex underlying lithology (granite, sandstone, tuff and graywacke). Along the Moselle River, the presence of positive Gd anomalies and a regular LREEs depletion/HREEs enrichment pattern on sandstone/limestone substrates were the most distinctive features. The Gd anomaly varied from 1.8 to 8.7, with anthropogenic Gd representing 45 to 88% of the total Gd. A linear relationship was obtained between the anthropogenic Gd flux and the cumulative population along the watershed. However, the magnitude of the Gd anomalies was shown to depend on the methodological approach chosen for their calculation. The use of a threshold value to identify the presence of an anthropogenic Gd anomaly may therefore be basin (and lithology) dependent, and care has to be taken in comparing results from different rivers or lithologies. Concentration of anthropogenic Gd in the Moselle River and its tributaries were close to, or above, the value of 20 ng/L reported in literature to elicit adverse biological effects in laboratory cell cultures. The ecotoxicological significance of Gd anomalies deserves further investigation because concentrations of anthropogenic Gd may also vary depending on the methodological approach used for calculating Gd anomalies. Unlabelled Image • REEs patterns of headstream waters depend on lithology • Gd anomaly calculation method influences its numerical value • The extent of Gd anomalies can be driven by changes in natural Gd levels • Anthropogenic Gd flux linearly correlates to cumulated population in the watershed • The ecotoxicological potential of anthropogenic Gd requires further investigation [ABSTRACT FROM AUTHOR]

This study newly investigates in detail the fate of inorganic chlorinated species and potential interference with other inorganic compounds such as phosphate, inorganic carbon and nitrogenous species during the electro-Fenton treatment of synthetic and reclaimed wastewater. A mathematical model was proposed to validate reaction pathways and rate constants of chlorinated species. The comparison of modeling results with experimental data of both synthetic and real solutions was quite good, with root mean square error (RMSE) values less than 0.084. Upon further testing, the results also showed that adding carbonate, phosphate and inorganic nitrogen species did not affect the chlorate and volatile chlorinated species accumulation subsequent to the decay of chloride ions during electro-Fenton. The established pathway in both synthetic and real chlorinated matrices could help to understand and predict the concentration profiles of chlorinated species in wastewater when implementing such electrocatalysis as a complementary treatment. This work also highlights the need to take into account the management of chlorinated intermediates when implementing this technology at larger scale. [ABSTRACT FROM AUTHOR]

Despite being an old process from the end of the 19 th century, electrosorption has attracted renewed attention in recent years because of its unique properties and advantages compared to other separation technologies and due to the concomitant development of new porous electrode materials. Electrosorption offer the advantage to separate the pollutants from wastewater with the possibility of selectively adsorbing and desorbing the targeted compounds. A comprehensive review of electrosorption is provided with particular attention given to the electrosorption of organic compounds, unlike existing capacitive deionization review papers that only focus on inorganic salts. The background and principle of electrosorption are first presented, while the influence of the main parameters (e.g., electrode materials, electrode potential, physico-chemistry of the electrolyte solutions, type of compounds, co-sorption effect, reactor design, etc.) is then detailed and the modeling and engineering aspects are discussed. Finally, the main output and future prospects about recovery studies and combination between electro-sorption/desorption and degradation processes are given. This review particularly highlights that carbon-based materials have been mostly employed (85% of studies) as porous electrode in organics electrosorption, while existing studies lack of electrode stability and durability tests in real conditions. These electrodes have been implemented in a fixed-bed reactor design most of the time (43% of studies) due to enhanced mass transport. Moreover, the electrode potential is a major criterion: it should be applied in the non-faradaic domain otherwise unwanted reactions can easily occur, especially the corrosion of carbon from 0.21 V/standard hydrogen electrode or the water oxidation/reduction. Furthermore, there is lack of studies performed with actual effluents and without addition of supporting electrolyte, which is crucial for testing the real efficiency of the process. The associated predictive model will be required by considering the matrix effect along with transport phenomena and physico-chemical characteristics of targeted organic compounds., (Copyright © 2021 Elsevier Inc. All rights reserved.)

The effect of the lockdown imposed to limit the spread of SARS-CoV-2 in France between March 14 and May 11, 2020 on the wastewater characteristics of two large urban areas (with between 250,000 and 300,000 inhabitants) was studied. The number of outward and inward daily commuters was extracted from national census databases related to the population and their commuting habits. For urban area A, with the larger number of daily inward commuters (110,000, compared to 53,000 for B), lockdown was observed to have an effect on the monthly load averages of chemical oxygen demand, biochemical oxygen demand, total Kjeldahl nitrogen, total suspended solids and total phosphorus, all of which decreased (confidence level of 95%). This decrease, which varied between 20% and 40% and reached 45% for COD, can be related to the cessation of catering and activities such as hairdressing, which generate large amounts of graywater. The ammonium loads, due to the use of toilets before leaving for work and after returning from work, remained constant. In the case of urban area B, lockdown had no noticeable effect. More data would be necessary in the long term to analyze the effect of changes in the balance between ammonia and carbon sources on the operation of wastewater treatment plants.

The World Health Organization Global Action Plan recommends integrated surveillance programs as crucial strategies for monitoring antibiotic resistance. Although several national surveillance programs are in place for clinical and veterinary settings, no such schemes exist for monitoring antibiotic-resistant bacteria in the environment. In this transnational study, we developed, validated, and tested a low-cost surveillance and easy to implement approach to evaluate antibiotic resistance in wastewater treatment plants (WWTPs) by targeting cefotaxime-resistant (CTX-R) coliforms as indicators. The rationale for this approach was: i) coliform quantification methods are internationally accepted as indicators of fecal contamination in recreational waters and are therefore routinely applied in analytical labs; ii) CTX-R coliforms are clinically relevant, associated with extended-spectrum β-lactamases (ESBLs), and are rare in pristine environments. We analyzed 57 WWTPs in 22 countries across Europe, Asia, Africa, Australia, and North America. CTX-R coliforms were ubiquitous in raw sewage and their relative abundance varied significantly (<0.1% to 38.3%), being positively correlated (p < 0.001) with regional atmospheric temperatures. Although most WWTPs removed large proportions of CTX-R coliforms, loads over 10 3 colony-forming units per mL were occasionally observed in final effluents. We demonstrate that CTX-R coliform monitoring is a feasible and affordable approach to assess wastewater antibiotic resistance status., (Copyright © 2020 The Authors. Published by Elsevier Ltd.. All rights reserved.)

To rapidly monitor the surface water quality in terms of organic pollution of an industrial river undergoing restoration, optical methods (UV-visible spectrometry and fluorescence) were applied in parallel to classical physical-chemical analyses. UV-visible spectra were analyzed using the maximum of the second derivative at 225 nm (related to nitrates), specific absorbance at 254 nm (SUVA 254 ), and the spectral slope between 275 and 295 nm (S 275-295 ) (related to the aromaticity and molecular weight of dissolved organic carbon). The synchronous fluorescence spectra (wavelength difference = 50 nm) exhibited a high variability in the composition of dissolved organic material between the upstream and downstream sections and also versus time. The principal components analysis of the entire set of synchronous fluorescence spectra helped to define three river sections with different pollution characteristics. Spectral decomposition was applied to the two most upstream sections: five fluorophores, classical in rivers impacted by domestic sewage and related to protein-like (λ ex  = 280 nm) and humic-like fluorescence (M-type with λ ex  ≈ 305-310 nm and C-type with λ ex  ≥ 335 nm), were identified. The irregular shape of the synchronous fluorescence spectra in the most downstream section is likely due to organic pollutants of industrial origin; however, their variability and the complexity of the spectra did not allow the further elucidation of their nature.

UV/titanium dioxide (TiO(2)) degradation of two xanthene dyes, erythrosine B (Ery) and eosin Y (Eos), was studied in a photocatalytic reactor. Photocatalysis was able to degrade 98% of Ery and 73% of Eos and led to 65% of chemical oxygen demand removal. Experiments in buffered solutions at different initial pH values reveal the pH dependence of the process, with better results obtained under acidic conditions due to the electrostatic attraction caused by the opposite charges of TiO(2) (positive) and of anionic dyes (negative). Batch activity tests under methanogenic conditions showed the high toxicity exerted by the dyes even at low concentrations (~85% with initial concentration of 0.3 mmol L(-1)), but the end products of photocatalytic treatment were much less toxic toward methanogenic bacteria, as detoxification of 85 ± 5% for Eos and 64 ± 7% for Ery were obtained. In contrast, the dyes had no inhibitory effect on the biogenic-carbon biodegradation activity of aerobic biomass, obtained by respirometry. The results demonstrate that photocatalysis combining UV/TiO(2) as a pretreatment followed by an anaerobic biological process may be promising for the treatment of wastewaters produced by many industries., (© 2012 Wiley Periodicals, Inc. Photochemistry and Photobiology © 2012 The American Society of Photobiology.)