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BACKGROUND This work focuses on the removal of perchloroethylene (PCE) from soils spiked with this hazardous chlorinated hydrocarbon and oil by a combination of two technologies: soil washing and anodic oxidation with diamond electrodes. The first attains the transfer of the pollutant from the soil to a soil washing fluid (SWF), from which the organics are then efficiently removed. RESULTS: Results show that high concentrations of sodium dodecyl sulphate (SDS) are required in the SWF for an efficient extraction of the chlorinated hydrocarbon and electrolysis has to be applied not only to the clarified liquid, but also to the interphase. The surfactant used interacts strongly with soil not only during the washing, but also during the electrolysis step. This interaction seems to play a protective role against the oxidation of SDS. The initial phase of the electrolysis is rather complex and there are several processes which modify the results importantly. CONCLUSIONS: Removal of PCE by electrolysis from soil is less efficient than its removal from synthetic solutions of this chlorinated pollutant. There are two first‐order kinetic zones, which indicate an important competition for the oxidation of the different organics contained in the SWF during the electrolysis. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND The design of new approaches that help to decrease both the environmental impact of industrial activities and the cost of existing water treatment technologies is becoming a key aspect of research. In the present work, an efficient and easy‐to‐use electrochemical device designed to dose iron coagulants is presented. RESULTS: The proposed device (the Electrochemically‐assisted Coagulant – production & dosing Unit, ECU) exhibits an efficient performance in the dosing of coagulants regardless of the ionic conductivity of the water matrixes tested (within the range 100 to 1000 µS cm−1), covering a wide range of potential real surface waters. The behaviour of the ECU device was compared to that of a conventional chemical dosing of iron, and showed better pH (pH ≈ 8 for ECU but < 4 for equivalent chemical dosing) and conductivity (decrease for ECU but increase up to 60% for equivalent chemical dosing) control. Moreover, the ECU unit produced a noticeable amount of Fe2+ ions, due to the limited access of atmospheric oxygen inside the device. CONLUSION: The device developed overcomes traditional chemical iron dosing and could be potentially applied in uses different from electrocoagulation, as it is the case of Fenton‐related technologies. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: BACKGROUND: This work is focused on the assessment of the performance of mini‐scale air‐breathing microbial fuel cells (MFCs), by monitoring the evolution of the bio‐electrogenic activity for a period of 40 days and by comparing the microorganisms populations developed in each of the MFCs after this period. RESULTS: Five MFCs were operated at sludge ages ranging from 1.4 to 10.0 days. Results showed the superb performance of the MFC operating under a sludge age of 2.5 days. Desulfuromonas, Syntrophothermus, Solitalea, Acholeplasma, Propionicimonas, Desulfobacula and Sphaerochaeta are proposed as potentially responsible for the bio‐electrogenic activity. CONCLUSIONS: Microbial population analysis through Illumina amplicon sequencing demonstrated that despite all MFCs being seeded with the same mixed culture inoculum, the biological cultures developed in the suspension and the biofilm are completely different and depend strongly on sludge age. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND This work compares the performance of three stacked microbial fuel cells constructed with different number of single-MFC (MFC1 with two stacked-MFCs, MFC2 with ten stacked-MFCs and MFC3 with twenty stacked-MFCs), and operated under the same conditions for one month. RESULTS According to results, algae suspensions can be used as fuel for MFC-stacks, although current efficiencies obtained are low. In comparing the effect of number of cells stacked on the performance of the stacks, it was found that the higher the number of cells stacked, the higher the energy harvested from algae. However, because of the very efficient consumption of COD in the first MFC of the stacks (not only by electrogenic but also by non-electrogenic microorganisms) and the sequential circulation of the fuel through the different cells of the stack, in all cases the systems ran out of fuel and this was reflected in lower production of electricity, compared with that expected taking into account the number of cells stacked. Results obtained from the polarization curves and the cathodic oxygen consumption also support this explanation. CONCLUSIONS Results demonstrate that algal biomass is a suitable fuel for energy generation using MFC technology and provides microorganisms not only of a carbon source but also with the required nutrients. However, the low coulombic efficiencies obtained in the three stacks indicate that feeding algae to MFC also promotes the formation of an important amount of non-electrogenic microorganisms that compete successfully with bioelectrogenic microorganisms for the substrate provided. © 2017 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND The aim of this work is to evaluate the effectiveness of complete treatment of soil spiked with 2,4-D, consisting of soil washing, followed by bioadsorption with activated sludge and electrochemical and photoelectrochemical oxidation of resulting wastewater using BDD anodes combined with UV light irradiation. RESULTS Results show that 2,4-D is very efficiently removed from synthetic soil by soil-washing without the use of surfactants. The effluent can be treated by bioadsorption with fresh activated sludge coming from a municipal wastewater treatment plant and the maximum adsorption capacity is 0.012 mg 2,4-D mg−1 biomass. Despite the low contact time between the biomass and the soil-washing effluent, results fit well to a Langmuir isotherm. CONCLUSIONS Photoelectrolysis with diamond anodes is more efficient than single electrolysis and the influence of potential radicalary oxidants produced on the anode surface from sulfate and chloride and activated by UV light can explain the better results. Both electrolysis and photoelectrolysis can lead to the complete mineralization of 2,4-D, regardless of the biomass/herbicide ratio applied in the previous bioadsorption process. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND Microbial fuel cells ( MFCs) can treat agro-industrial wastewater, but only a few studies have reported the treatment of winery waste and much work is needed in order to develop this interesting application of MFC technology, in particular in evaluating how the unfavorable COD/N and COD/P ratios may affect the MFC performance. In this work, a dual chamber MFC was used to treat real effluents from wine processing factories. RESULTS The MFC was not efficient in terms of COD removal, even when nutrients concentration was increased and daily removals which oscillated around 1000 mg L-1 d-1 were observed during the complete experimental period, with COD removals around 17%. Increases in the phosphorus and nitrogen concentrations positively influenced the production of electricity. By increasing the concentration of phosphorus and nitrogen, Coulombic efficiency was increased from 2% to almost 15%, and maximum power density from 105 to 465 mW m-2. CONCLUSIONS Results demonstrate that electricity can be produced efficiently and that the unbalanced nutrients/ COD ratio is a major challenge in the treatment of winery wastewater, in spite of the very high organic load contained in this type of wastewater. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: In recent years, the application of electrochemical wastewater treatment processes has proven to be very efficient in the removal of recalcitrant organic compounds. However, the scale-up of the boron-doped diamond (BDD) anode system for industrial applications has not been sufficiently evaluated. This study assesses the effect of increasing the number of compartments in the same electrochemicalmodule (DiaCell® 1001) on the treatment of synthetic wastewater with pesticide 2,4-D and chlorides. This commercial module can be considered to be a stack of cells, in which the number of single cells varies from 2-10 and the anode areas range from 140-700 cmâ'2. RESULTS: The results of the study demonstrate that an increase in the number of cells and a decrease in the resulting current density at the same current intensity caused an increase in the removal and mineralisation rates. Complete mineralisation was attained in all configurations tested. The production of hazardous species, such as chlorates and perchlorates, are also affected by the number of stacked cells, which causes them to be positioned lower in the stack due to the large number of cells. CONCLUSIONS: No distinct differences in electrochemical efficiency are observed among the different configurations tested. However, a distinct improvement in the energy efficiency (g kWhâ'1) with an increase in the number of stacked cells is observed due to the reduced stack potential caused by applying the same current intensity to the stack with the higher number of cells. [ABSTRACT FROM AUTHOR]

BACKGROUND: In the search for novel technologies for the treatment of urban wastewater, combined anaerobic-algae membrane bioreactors have become a very interesting choice. Recovery of algae produced in these reactors has become the key point to obtain a good economic efficiency with this technology. In thiswork, electrocoagulation is studied as an alternative for the coarse removal of algae from a biological culture. RESULTS: Results demonstrate that the electrochemical technology is a suitable technology for this purpose allowing the removal of more than 90% of the algae without modifying significantly the pH and with an operating cost below 0.04 € m−3. The same general trends are observed for applied current charge and current density supplied when aluminum or iron are used as electrodes although aluminum was muchmore efficient. CONCLUSIONS: The dose of coagulant reagents required is very low, indicating that coagulant generated in the process is very efficiently used. The best results in terms of algae and turbidity removals are obtained operating at low current densities with aluminum electrodes. According to pH and z-potential values, insoluble metal hydroxide and anion M(OH)4- seems to be the primary coagulation species involved in the electrocoagulation process. [ABSTRACT FROM AUTHOR]

BACKGROUND This work aims to describe the removal of a model anion (nitrate) from clay soils using electrokinetically assisted soil flushing coupled with permeable reactive barriers consisting of beds of anion exchange resin and to assess the influence of the electric field on the efficiency of this technology. RESULTS Experiments have been carried out at bench scale with spiked soil using electric fields ranging from 1.0 to 2.0 V cm−1. Results show that removal of nitrates with this remediation technology is very efficient. About 90% of the nitrates contained in the soil can be removed in less than 1 week of operation with energy consumptions below 75 kWh m−3. An electric field of 1.2 V cm−1 was used because no improvements were found operating at higher voltages. CONCLUSIONS The proposed technology for the removal of nitrates is very effective, making it very promising for the removal of anionic pollutants from soils. The main path of change observed is the direction from anode to cathode. Dispersion in the axial direction is very small. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND In this work, the electrolysis of dimethyl phthalate ( DMP, a widely-use plasticizer) with conductive-diamond anodes is studied. RESULTS Results show that this technology is capable of depleting this pollutant in a wide range of initial concentrations. Although mass transfer limits the kinetics of the process, there is a significant contribution of mediated oxidation and the rate of the processes improve with increasing current density, while the efficiency decreases. A first stage in the oxidation of DMP consists of the attack on the methyl ester groups, and monomethyl phthalate and phthalate are the main aromatic intermediates. Further oxidation of these species results in the formation of maleic and oxalic acid, which behave as intermediates and are completely mineralized during the electrolysis. The presence of chloride in water leads to the formation of many more aromatic chlorinated intermediates from the action of hypochlorite on aromatics intermediates. Intermediates found and oxidation mechanisms proposed are consistent with those reported in the literature for other advanced oxidation processes. CONCLUSIONS DMP, TOC (total organic carbon) and COD (chemical oxygen demand) can be successfully removed using electrolysis with conductive-diamond anodes. DMP removal is faster than that of COD and TOC indicating the formation of reaction intermediates. © 2013 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

BACKGROUND: Removal of triclosan by conductive-diamond electrochemical oxidation (CDEO) and sonoelectrochemical oxidation (CDSEO), either in methanol/water or methanol solutions is studied in the range of concentration 0.1 to 100 mg dm−3. Effects of current density and of electrolyte on the process efficiency are assessed. RESULTS: Concentration of triclosan can be removed below the detection limit of HPLC. In methanol/water solutions, there are two stages: a rapid decrease in the concentration and a less efficient process in which the rate is slower. In methanol solutions, experimental results clearly fit first-order kinetics. Mediated oxidation plays a significant role. Electrolyses in sulphate media are more efficient than in chloride media and the second low-rate stage in methanol/water solution appears for higher triclosan removal. The main intermediates are catechol, chlorohydroquinone, 4-chlorocatechol, acetic acid and dichloroacetic acid. They were only detected during the electrolysis of highly concentrated solution, suggesting a very energetic oxidation. CONCLUSIONS: CDEO and CDSEO are very efficient for the removal of triclosan. CDSEO improves mass-transfer processes and gives a more efficient removal at lower concentrations. The removal of methanol is improved significantly, in spite of its concentration being well over the limiting value for mass transport control. The reaction sequence for triclosan mineralization is consistent with literature reports. © 2012 Society of Chemical Industry [ABSTRACT FROM AUTHOR]