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1
Kukunoor, Nagesh Sri. "Separation of ultrafines in dispersions using electrocoagulation." Thesis, Georgia Institute of Technology, 1990. http://hdl.handle.net/1853/11755.
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Dobson, Regina Louise. "Electrocoagulation concept for the separation of ultrafines." Thesis, Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/11855.
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Gunukula, Sampath Reddy. "ELECTROCOAGULATION/FLOTATION TREATMENT OF SYNTHETIC SURFACE WATER." Cleveland State University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=csu1304363574.
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Thole, Andile. "Application and evaluation of electrocoagulation techniques for the treatment of dyehouse effluents." Thesis, Cape Peninsula University of Technology, 2015. http://hdl.handle.net/20.500.11838/923.
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Thesis submitted in fulfillment of the requirements for the degree Master of Technology Chemical Engineering In the Faculty of Engineering at the Cape Peninsula University of TechnologyWet textile processing (WTP), is faced with many challenges that are related to operating costs and market competiveness. WTP uses large amounts of water and electricity, which constitute a big portion of operating costs of dyehouses and other costs are related to releasing large quantities of water, high concentrations of dyes and chemicals into the textile effluents with possible effluents discharge limits (EDL) penalty charges if EDL are exceeded. EDL penalty costs had become a normative part of the operating costs for some WTP textile factories, making the EDL penalties, a monthly cost item, because water utilities and the effluent discharge are not controlled and optimized. Cotton dyeing is a complicated chemi-physical-sorption process that is not easy to perform efficiently. Inefficient dyeing (off-shades and un-level dyeing) sometimes results in several reprocessing steps, leading to mega litres of water and chemical usage. Inefficient dyeing can also lead to higher concentrations of dyes and chemicals in the dyeing effluents. The main objectives of this study were to investigate the applicability of electrocoagulation (EC) in treatment of reactive dyes textile effluents for safe discharge into sewers or forreuse and also to evaluate EC reaction kinetics in removal of various pollutants from reactive dyes textile effluent with a batch electrocoagulation reactor (ECR). To achieve these objectives; textile effluents to be used had to be created instead of using factory effluents because textile effluents vary between dyeing batches and reaction kinetics study require constant and consistent composition of effluents. This was done by following the standard commercial sample cotton-dyeing procedures. The dyeing and pre-bleaching procedures were formulated from literature sources. The dyeing and pre-bleaching were done to create the reactive dyes textile effluents with commercial sample dyeing machines; Washtec-P and Pyrotec-MB2 at liquor ratios of 10:1 and 20:1.
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Rincon, Guillermo. "Kinetics of the electrocoagulation of oil and grease." ScholarWorks@UNO, 2011. http://scholarworks.uno.edu/td/131.
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Research on the electrocoagulation (EC) of hexane extractable materials (HEM) has been conducted at the University of New Orleans using a proprietary bench-scale EC reactor. The original reactor configuration forced the fluid to follow a vertical upward-downward path. An alternate electrode arrangement was introduced so that the path of flow became horizontal. Both configurations were evaluated by comparing the residence time distribution (RTD) data generated in each case. These data produced indication of internal recirculation and stagnant water when the fluid followed a vertical path. These anomalies were attenuated when the fluid flowed horizontally and at a velocity higher than 0.032 m s-1 . A series of EC experiments were performed using a synthetic emulsion with a HEM concentration of approximately 700 mg l-1. It was confirmed that EC of HEM follows first-order kinetics, and kinetic constants of 0.0441 s-1 and 0.0443 s-1 were obtained from applying both the dispersion and tanks-in-series (TIS) models, respectively. In both cases R2 was 0.97. Also, the TIS model indicated that each cell of the EC behaves as an independent continuous-stirred-tank reactor.
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Mechelhoff, Martin. "Electrochemical investigation of electrocoagulation reactors for water purification." Thesis, Imperial College London, 2009. http://hdl.handle.net/10044/1/8896.
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Holt, Peter Kevin. "ELECTROCOAGULATION: UNRAVELLING AND SYNTHESISING THE MECHANISMS BEHIND A WATER TREATMENT PROCESS." Thesis, The University of Sydney, 2002. http://hdl.handle.net/2123/624.
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Electrocoagulation is an empirical (and largely heuristic) water treatment technology that has had many different applications over the last century. It has proven its viability by removing a wide range of pollutants. The approach to reactor design has been haphazard, however, with little or no reference to previous designs or underlying principles. This thesis reviewed these reactor designs, identifying key commonalities and synthesising a new design hierarchy, summarised by three main decisions: 1. Batch or continuous operation; 2. Coagulation only or coagulation plus flotation reactors, and; 3. Associated separation process if required. This design decision hierarchy thereby provides a consistent basis for future electrocoagulation reactor designs. Electrochemistry, coagulation, and flotation are identified as the key foundation sciences for electrocoagulation, and the relevant mechanisms (and their interactions) are extracted and applied in an electrocoagulation context. This innovative approach was applied to a 7 L batch electrocoagulation reactor treating clay-polluted water. Structured macroscopic experiments identified current (density), time, and mixing as the key operating parameters for electrocoagulation. A dynamic mass balance was conducted over the batch reactor, for the first time, thereby enabling the extraction of a concentration profile. For this batch system, three operating stages were then identifiable: lag, reactive, and stable stages. Each stage was systematically investigated (in contrast to the previous ad hoc approach) with reference to each of the foundation sciences and the key parameters of current and time. Electrochemical behaviour characterised both coagulant and bubble generation. Polarisation experiments were used to determine the rate-limiting step at each electrode's surface. Consequently the appropriate Tafel parameters were extracted and hence the cell potential. At low currents both electrodes (anode and cathode) operated in the charge-transfer region. As the current increased, the mechanism shifted towards the diffusion-limited region, which increased the required potential. Polarisation experiments also define the operating potential at each electrode thereby enabling aluminium's dissolution behaviour to be thermodynamically characterised on potential-pH (Pourbaix) diagrams. Active and passive regions were defined and hence the aluminium's behaviour in an aqueous environment can now be predicted for electrocoagulation. Novel and detailed solution chemistry modelling of the metastable and stable aluminium species revealed the importance of oligomer formation and their rates in electrocoagulation. In particular, formation of the positively trimeric aluminium species increased solution pH (to pH 10.6), beyond the experimentally observed operable pH of 9. Thereby signifying the importance of the formation kinetics to the trimer as the active coagulant specie in electrocoagulation. Further leading insights to the changing coagulation mechanism in electrocoagulation were possible by comparison and contrast with the conventional coagulation method of alum dosing. Initially in the lag stage, little aggregation is observed until the coagulant concentration reaches a critical level. Simultaneously, the measured zeta potential increases with coagulant addition and the isoelectric point is attained in the reactive stage. Here a sorption coagulation mechanism is postulated; probably charge neutralisation, that quickly aggregates pollutant particles forming open structured aggregates as indicated by the low fractal dimension. As time progresses, pollutant concentration decreases and aluminium addition continues hence aluminium hydroxide/oxide precipitates. The bubbles gently sweep the precipitate through the solution, resulting in coagulation by an enmeshment mechanism (sweep coagulation). Consequently compact aggregates are formed, indicating by the high fractal dimension. Flotation is an inherent aspect of the batch electrocoagulation reactor via the production of electrolytic gases. In the reactor, pollutant separation occurs in situ, either by flotation or settling. From the concentration profiles extracted, original kinetic expressions were formulated to quantify these competing removal processes. As current increases, both settling and flotation rate constants increased due to the additional coagulant generation. This faster removal was offset by a decrease in the coagulant efficiency. Consequently a trade-off exists between removal time and coagulant efficiency that can be evaluated economically. A conceptual framework of electrocoagulation is developed from the synthesis of the systematic study to enable a priori prediction. This framework creates predictability for electrocoagulation, which is innovative and original for the technology. Predictability provides insights to knowledge transfer (between batch and continuous), efficient coagulant and separation path, to name just a few examples. This predictability demystifies electrocoagulation by providing a powerful design tool for the future development of scaleable, industrial electrocoagulation water treatment design and operation process.
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Perng, Yuan-Shing, and Ha-Manh Bui. "Decolorization of Reactive Red 195 solution by electrocoagulation process." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2015. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-176597.
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In this study, the application of bipolar electrocoagulation (EC) with iron electrode has been assessed for color removal of simulated wastewater containing Reactive Red 195. The influence of initial pH, sodium sulfate concentration, initial dye concentration, electrolysis time, and electric current were examined. The optimum operational parameters were found to be pH =11, concentration of dye = 50 mg L-1, sodium sulfate concentration = 1200 mg L-1, electrolysis time = 5 min and electric current = 4 A. In such condition, color removal efficiency achieved over 99%. This result indicates that EC can be used as an efficient and “green” method for color removal from reactive dye solutionTrong nghiên cứu này, quá trình khử màu nhuộm hoạt tính (Reactive Red 195) được khảo sát bằng hệ thống keo tụ điện hóa điện cực kép, với vật liệu sắt. Các yếu tố ảnh hưởng đến quá trình khử màu như pH, nồng độ màu nhuộm, nồng độ muối Na2SO4, thời gian phản ứng và cường độ dòng được lựa chọn nghiên cứu. Kết quả cho thấy hệ thống điện hóa trên loại gần như hoàn toàn màu nhuộm với hiệu suất đạt trên 99 % tại pH 11, nồng độ màu 50 mgL-1 và nống độ muối Na2SO4 1200 mgL-1 trong khoảng thời gian 5phút. Kết quả trên cho thấy keo tụ điện hóa có thể xem là một phương pháp xử lý hiệu quả và “xanh” trong việc loại bỏ hoàn toàn màu từ nước thải nhuộm hoạt tính
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Andrade, Milton. "Heavy metal removal from bilge water by electrocoagulation treatment." ScholarWorks@UNO, 2009. http://scholarworks.uno.edu/td/1092.
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The purpose of this research was to observe the removal efficiency for copper (Cu), nickel (Ni), and zinc (Zn) using Electrocoagulation (EC) technique in a continuous flow reactor with a synthetic bilge water emulsion; and additionally, to discuss the operation cost of the treatment. The optimal configuration for EC treatment used combined electrodes, aluminum and carbon steel; flow rate of 1 L/min; effluent recycling and 7.5 amps; this optimal configuration achieved 99% of zinc removal efficiency, 70% of both, copper and nickel removal efficiency, and low operation costs. The current intensity did not have significance incidence on the removal efficiency. The analysis of cost per gram of removed contaminant indicated that nickel had an average cost of $1.95 per gram removed, zinc and copper had $0.60 and $0.88 per gram removed, respectively. To develop additional experiments with the EC reactor are required in order to optimize metal removal efficiency.
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MAMBRINI, PIERRE. "Traitement palliatif des stenoses neoplasiques oesophagiennes par sonde d'electrocoagulation bipolaire." Aix-Marseille 2, 1994. http://www.theses.fr/1994AIX20838.
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CASQUEIRA, RUI DE GOES. "REMOVAL OF ZINC AND CADMIUM USING ELECTROFLOTATION AND ELECTROCOAGULATION TECHNIQUE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=6095@1.
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CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOA remoção de metais pesados presentes em soluções aquosas em concentrações reduzidas (entre 10-7 e 10-4 moles.dm-3) não encontra resultados satisfatórios nos métodos tradicionais que não conseguem a Remoção adequada para o enquadramento do efluente nos parâmetros de emissão. A técnica de remoção de metais pesados presentes em solução através da flotação iônica vêm sido estudada como uma possibilidade viável capaz de tratar grandes volumes de efluentes em áreas relativamente pequenas e que aceita combinações com outras técnicas, como a coagulação. O uso da eletroflotação agrega vantagens ao processo de flotação, principalmente quanto à uniformidade e ao tamanho diminuto das bolhas formadas eletroliticamente. Como complementação do processo de eletroflotação, a eletrocoagulação tem sido comumente estudada como uma técnica complementar ao processo de eletroflotação. Este trabalho teve como objetivo projetar e construir uma unidade experimental para ensaios de eletroflotação e eletrocoagulação, e estudar algumas variáveis mais importantes que influenciam o processo de eletroflotação e a influência do uso conjugado da eletroflotação com a eletrocoagulação na remoção de zinco e cádmio contido em soluções sintéticas contendo 20mg.l-1 do metal e o coletor aniônico dodecilsulfato de sódio (DSS). Foi estudada a influência de diversos parâmetros: pH, concentração de coletor, tensão, densidade de corrente e força iônica. A introdução de eletrodos para a produção in situ do agente coagulante também foi observada. Os resultados obtidos mostraram que o equipamento utilizado é capaz de produzir resultados satisfatórios para remoção de zinco e cádmio dentro da faixa de valores investigada. Na presença de DSS na razão de três para um e em pH da solução de entrada por volta de sete, foram obtidos os melhores resultados, quando foi registrado até 96 por cento de remoção.
The removal of heavy metals from diluted aqueous solutions (in the range of 10-3 to 10-4 models.dm-3) do not produce good results using classical methods which cant t reach enough removal efficiency in agreement with environmental quality standards. The use of ionic flotation as an efficient method to remove heavy metals has been studied as a promising technique to treat large amount of effluents in a relatively small units which may be used combined with others techniques a coagulation. The use of electroflotation joins some advantages to the flotation process, mainly due the small bubble size formed on the electrodes surface. The electrocoagulation, applied with the electroflotation, has been studied as a complementary operation working with the electroflotation. The aim of this work was to project and build an electroflotation/electrocoagutation experimental unitm some of its important variables and the influence of its variables in the removal of zinc and cadmium from synthetic solutions wich contains 20 mg.l-4 of each metal concentration and sodium dodecil sulphate (SDS) as an anionic collector. The influence of some important parameters: pH, collectos concentrations, tension, current density and ionic strength were analyzed. An introduction of a pair of electrodes of aluminum and stainless steel to produce the coagulant agents was also investigated to bring the electrocoagulation of the particles. The results showed that the experimental unit can bring satisfactory results of removal of the metals withim the range studied. In the best results, 96 percent of removal of cadmium was obtained using SDS as a collector in stoichiometric proportion equal to three and inlet pH around seven.
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RIBEIRO, THIAGO DA SILVA. "FUNDAMENTAL ASPECTS OF BORON REMOVAL FROM WASTEWATERS BY ELECTROCOAGULATION METHOD." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2017. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=36398@1.
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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROCOORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR
FUNDAÇÃO DE APOIO À PESQUISA DO ESTADO DO RIO DE JANEIRO
PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO
BOLSA NOTA 10
Compostos de boro são utilizados na indústria metalúrgica, microeletrônica, de vidros, na agricultura, etc. Esse elemento é um micronutriente essencial no desenvolvimento de microrganismos, plantas, animais e humanos. No entanto, pode ser tóxico em grandes concentrações e por isso necessita ser removido de águas e efluentes. No Brasil, o limite padrão é de 0,5mg/L para águas doces de classe I e II, estabelecido pela resolução do Conama 357/2005. Por sua vez, a resolução do Conama 430/2011 estabelece um padrão de lançamento de efluentes de 5mg/L. A presente dissertação tem como objetivo geral estudar a remoção de boro por eletrocoagulação para o tratamento de águas e efluentes contendo boro, utilizando uma célula com um arranjo de 4 eletrodos de alumínio (2 catodos e 2 anodos) monopolares em paralelo. Os resultados obtidos mostram que o processo de eletrocoagulação é uma alternativa viável para a remoção de boro, e alcança eficiências em torno de 70 por cento (em pH inicial igual à 4; densidade de corrente igual à 18,75mA/cm2 e tempo de eletrólise igual à 90min). O modelo cinético que melhor descreve a remoção de boro foi o de pseudo-primeira ordem. O modelo de Langmuir se ajustou muito bem aos dados experimentais obtidos. O valor de qm obtido pelo modelo de Langmuir refletiu a elevada capacidade de adsorção máxima (qm é igual à 334mg/g). Através das análises por Microscopia Eletrônica de Varredura (MEV) e por Espectroscopia de Energia Dispersiva (EDS) na superfície dos eletrodos, observou-se a presença de corrosão do tipo localizada nos catodos e a corrosão do tipo uniforme nos anodos. A morfologia do lodo produzido no processo de eletrocoagulação foi analisada por MEV, indicando a presença de uma morfologia heterogênea na superfície, enquanto que a análise por Difração de Raios-X (DRX) apresentou picos largos característicos de um material amorfo e a fase de alumínio predominante foi a boehmita, AlO(OH), finalmente, através da análise por Espectroscopia por Perda de Energia de Elétrons (EELS) foi possível a detecção do boro no lodo, além da detecção de alumínio e de oxigênio. Diante dos resultados obtidos no estudo de otimização a partir da Metodologia de Superfície de Resposta (RSM) constatou-se que o desenvolvimento de um modelo matemático por análise de regressão possibilitou a avaliação do efeito das variáveis independentes (densidade de corrente, pH inicial e tempo de eletrólise) e as suas interações na remoção de boro.
Boron compounds are used in the metallurgical industry, microelectronics, glassware, agriculture, etc. This element is an essential micronutrient in the development of microorganisms, plants, animals and humans. However, it can be toxic in high concentrations and therefore needs to be removed from water and effluent. In Brazil, the standard limit is 0.5mg/L for Class I and II freshwaters, established by Conama Resolution 357/2005. In turn, the Conama 430/2011 resolution establishes an effluent discharge standard of 5mg/L. The present dissertation aims to study the removal of boron by electrocoagulation for the treatment of water and effluents containing boron, using a cell with an arrangement of 4 monopolar aluminum electrodes (2 cathodes and 2 anodes) in parallel. The results show that the electrocoagulation process is a viable alternative for the removal of boron and reaches efficiencies around 70 per cent (at initial pH equals to 4, current density equals to 18.75mA/cm2 and electrolysis time equals to 90min). The kinetic model that best describes the removal of boron was pseudo-first order. The Langmuir model fitted very well to the experimental data obtained. The value of qm obtained by the Langmuir model reflected the high maximum adsorption capacity (qm equals to 334mg/g). Through the analysis by Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS) on the surface of the electrodes, it was observed the presence of pitting corrosion in the cathodes and uniform corrosion in the anodes. The morphology of the sludge produced in the electrocoagulation process was analyzed by SEM, indicating the presence of a heterogeneous surface morphology, while the X-ray diffraction (XRD) analysis showed broad peaks characteristic of an amorphous material and the predominant aluminum phase was boehmite, AlO(OH), finally, through the Electron Energy Loss Spectroscopy (EELS) analysis, it was possible to detect boron in the sludge, as well as aluminum and oxygen. In view of the results obtained in the optimization study from the Response Surface Methodology (RSM), it was verified that the development of a mathematical model by regression analysis made possible the evaluation of the effect of the independent variables (current density, initial pH and time of electrolysis) and their interactions in the removal of boron.
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Lin, Jack. "Pre-treatment of coal seam water with coagulation and electrocoagulation." Thesis, Queensland University of Technology, 2017. https://eprints.qut.edu.au/105358/4/Jack_Lin_Thesis.pdf.
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This thesis examined innovative methods for pre-treatment of coal seam water. In order to prevent scaling and fouling of downstream reverse osmosis membranes we investigated both electrocoagulation and chemical coagulation using aluminium and iron based electrodes and/or coagulants. Application of electrocoagulation was found to significantly reduce the presence of problematic dissolved species such as silica and also alkaline earth ions which potentially can scale membranes and equipment. Chemical coagulation could also remove dissolved silica from simulated coal seam water samples but was found to be relatively ineffective when treating real coal seam water. The future study of electrocoagulation is worthy in order to determine its applicability to a wider range of coal seam water compositions and to minimise costs of use.
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Yehya, Tania. "Etude des procédés electrochimiques et biologiques pour le traitement des eaux : application à l'élimination des nitrates et de la carbamazépine." Thesis, Clermont-Ferrand 2, 2015. http://www.theses.fr/2015CLF22660/document.
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L'eau est vitale pour l'existence de tous les organismes vivants, mais cette ressource précieuse est de plus en en plus menacée et polluée à cause de l’augmentation de la demande en eau potable qui résulte à la fois de l’accroissement de la population mondiale mais aussi de l’activité économique tant au niveau de l’agriculture que de l’industrie. La préservation de cette ressource est aujourd'hui l'une des premières préoccupations de la recherche dans le domaine du traitement des eaux. Dans ce travail, l’élimination de deux polluants typiques des activités humaines, les nitrates et la carbamazépine, est étudiée au moyen de méthodes de traitements électrochimiques et biologiques non-conventionnelles. Le travail se concentre d'une part sur l'électrocoagulation (EC) qui associe les avantages d'être non-spécifique et de combiner plusieurs mécanismes de dépollution simultanés (adsorption, électro-oxydation ...); d’autre part, un traitement biologique innovant de faible coût utilisant une algue verte, Ankistrodesmus braunii, a été développé. Enfin, les avantages, limitations et perspectives de ces deux procédés sont comparés à ce qui existe dans la littérature et sont discutésWater is vital to the existence of all living organisms, but this valued resource is increasingly being threatened and polluted as human populations and activities grow and demand more water of high quality for domestic purposes and economic activities. Wastewater treatment for resource preservation is nowadays one of the first concerns of research in this field of science. In this work, two typical pollutants from agriculture and domestic activity, Nitrates and Carbamazepine, are quantitatively addressed by non-conventional electrochemical and biological treatment methods. The study focuses, on the one side, on electrocoagulation (EC) that exhibits the advantages to be non-specific and to combine various depollution mechanisms (adsorption, electro-oxidation...) that act simultaneously; on the other side, innovative and low-cost biological treatments using green algae, Ankistrodesmus braunii, are developed. Finally, the respective advantages, limitations and perspectives of these processes are compared to the literature and discussed
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Holt, Peter Kevin. "Electrocoagulation unravelling and synthesising the mechanisms behind a water treatment process /." Connect to full text, 2002. http://hdl.handle.net/2123/624.
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Thesis (Ph. D.)--University of Sydney, 2003.Title from title screen (viewed Apr. 28, 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Dept. of Chemical Engineering, Faculty of Engineering. Degree awarded 2003; thesis submitted 2002. Includes bibliography. Also available in print form.
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Hansson, Henrik. "Reduction of Pollutants in Stormwaterand Processwater from the WoodIndustry by Electrocoagulation." Thesis, University of Kalmar, School of Pure and Applied Natural Sciences, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:hik:diva-2530.
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Although wood floor production does not use water in the production process, water consumptionis related to cleaning and washing of floor and machineries in different steps of the process line,which generate a number of small flows that are highly polluted.Besides this, the industry has a need to store large amounts of wood outside to be able to havecontinuity in the production. This takes up a lot of space outdoors and once it rains the water thathas been in contact with wood, oil and metals forms stormwater, which transports pollutants.Stormwater has for a long time not been seen as a problem and has often been discharged intorecipient water bodies without any treatment. During cold seasons, this also involves snowmelt thatcan transport high concentrations of different pollutants.This report describes the composition of process- and stormwater from a wood floor industry inNybro, Sweden regarding parameters such as COD, phenol, tannin and lignin. The concentrationsof phenols in the stormwater were found in a range considered toxic to marine life.Regarding the process water, high values was found for COD (Chemical Oxygen Demand) and forother substances and elements potentially toxic (e.g. formaldehyde, wood resins, detergents andmetals). If these waters are directly released to a sewage treatment plant without any pre-treatmentprocess it can disturb the plant treatment efficiency; if released to a recipient water body, it cancause oxygen deficiency and consequently, death to marine life.The possibility of reducing the levels of pollutants through the use of electrocoagulation has beenexamined in this study. This has been done both for process water and stormwater from the woodfloor industry. A 250 ml batch unit for electrocoagulation EC was setup with iron (Fe) andaluminium (Al) electrodes for treating process water and stormwater. The results show that the ECprocess can reduce COD concentration from stormwater at least 70%. On the other hand, lessefficiency of EC for treating process water was observed.A method for simulating a snowmelt period in lab scale was also developed. Snow collected from awood floor industry was melted according to real temperature and the quality of these samples hasthen been compared to on-site samples of stormwater
Development of an integrated approach for industrial wastewater and stormwater management in the wood-industry sector
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Holt, Peter Kevin. "ELECTROCOAGULATION: UNRAVELLING AND SYNTHESISING THE MECHANISMS BEHIND A WATER TREATMENT PROCESS." University of Sydney. Chemical Engineering, 2003. http://hdl.handle.net/2123/624.
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Electrocoagulation is an empirical (and largely heuristic) water treatment technology that has had many different applications over the last century. It has proven its viability by removing a wide range of pollutants. The approach to reactor design has been haphazard, however, with little or no reference to previous designs or underlying principles. This thesis reviewed these reactor designs, identifying key commonalities and synthesising a new design hierarchy, summarised by three main decisions: 1. Batch or continuous operation; 2. Coagulation only or coagulation plus flotation reactors, and; 3. Associated separation process if required. This design decision hierarchy thereby provides a consistent basis for future electrocoagulation reactor designs. Electrochemistry, coagulation, and flotation are identified as the key foundation sciences for electrocoagulation, and the relevant mechanisms (and their interactions) are extracted and applied in an electrocoagulation context. This innovative approach was applied to a 7 L batch electrocoagulation reactor treating clay-polluted water. Structured macroscopic experiments identified current (density), time, and mixing as the key operating parameters for electrocoagulation. A dynamic mass balance was conducted over the batch reactor, for the first time, thereby enabling the extraction of a concentration profile. For this batch system, three operating stages were then identifiable: lag, reactive, and stable stages. Each stage was systematically investigated (in contrast to the previous ad hoc approach) with reference to each of the foundation sciences and the key parameters of current and time. Electrochemical behaviour characterised both coagulant and bubble generation. Polarisation experiments were used to determine the rate-limiting step at each electrode�s surface. Consequently the appropriate Tafel parameters were extracted and hence the cell potential. At low currents both electrodes (anode and cathode) operated in the charge-transfer region. As the current increased, the mechanism shifted towards the diffusion-limited region, which increased the required potential. Polarisation experiments also define the operating potential at each electrode thereby enabling aluminium�s dissolution behaviour to be thermodynamically characterised on potential-pH (Pourbaix) diagrams. Active and passive regions were defined and hence the aluminium�s behaviour in an aqueous environment can now be predicted for electrocoagulation. Novel and detailed solution chemistry modelling of the metastable and stable aluminium species revealed the importance of oligomer formation and their rates in electrocoagulation. In particular, formation of the positively trimeric aluminium species increased solution pH (to pH 10.6), beyond the experimentally observed operable pH of 9. Thereby signifying the importance of the formation kinetics to the trimer as the active coagulant specie in electrocoagulation. Further leading insights to the changing coagulation mechanism in electrocoagulation were possible by comparison and contrast with the conventional coagulation method of alum dosing. Initially in the lag stage, little aggregation is observed until the coagulant concentration reaches a critical level. Simultaneously, the measured zeta potential increases with coagulant addition and the isoelectric point is attained in the reactive stage. Here a sorption coagulation mechanism is postulated; probably charge neutralisation, that quickly aggregates pollutant particles forming open structured aggregates as indicated by the low fractal dimension. As time progresses, pollutant concentration decreases and aluminium addition continues hence aluminium hydroxide/oxide precipitates. The bubbles gently sweep the precipitate through the solution, resulting in coagulation by an enmeshment mechanism (sweep coagulation). Consequently compact aggregates are formed, indicating by the high fractal dimension. Flotation is an inherent aspect of the batch electrocoagulation reactor via the production of electrolytic gases. In the reactor, pollutant separation occurs in situ, either by flotation or settling. From the concentration profiles extracted, original kinetic expressions were formulated to quantify these competing removal processes. As current increases, both settling and flotation rate constants increased due to the additional coagulant generation. This faster removal was offset by a decrease in the coagulant efficiency. Consequently a trade-off exists between removal time and coagulant efficiency that can be evaluated economically. A conceptual framework of electrocoagulation is developed from the synthesis of the systematic study to enable a priori prediction. This framework creates predictability for electrocoagulation, which is innovative and original for the technology. Predictability provides insights to knowledge transfer (between batch and continuous), efficient coagulant and separation path, to name just a few examples. This predictability demystifies electrocoagulation by providing a powerful design tool for the future development of scaleable, industrial electrocoagulation water treatment design and operation process.
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Popovic, Ivan [Verfasser]. "Electrocoagulation in the separation process of used bentonite suspensions / Ivan Popovic." Düren : Shaker, 2020. http://d-nb.info/1217164014/34.
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GONZALES, LORGIO GILBERTO VALDIVIEZO. "THE EFFECT OF DIFFERENT METALLIC ELECTRODES ON THE ELECTROCOAGULATION OF OILY WASTEWATER." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2008. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=13045@1.
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COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORNo presente trabalho, foi avaliado num modo sistemático o processo de eletrocoagulação (EC) usando eletrodos de alumínio e ferro como material de anodo e aço inoxidável como material de catodo, operando com diferentes parâmetros tais como: concentração inicial do óleo, distanciamento entre os eletrodos, relação área-volume (SA/V) e densidade de corrente. A redução da demanda química de oxigênio (DQO) e turbidez foram às principais variáveis respostas analisadas. Os ensaios foram feitos em batelada com um efluente sintético (5,1 litros) e com agitação magnética (150 rpm). A densidade de corrente e a relação SA/V foram os parâmetros com maior influência no processo. O aumento deles reduz notoriamente o tempo de tratamento. Os resultados mostraram que a eletrocoagulação, para os dois tipos de materiais (Fe/Al), conseguem uma excelente redução da DQO e da turbidez nas seguintes condições experimentais: densidade de corrente, 9,4 mA/cm(2), distanciamento entre os eletrodos, 10 mm, relação área-volume(SA/V), 30,35 m(2)/m(3) e 30 minutos de operação. Eficiências de redução de 99% e 98,3% foram alcançadas para a DQO e a turbidez com anodos de alumínio. Do mesmo modo 94,8% da DQO e 98,5% da turbidez para o caso do ferro foi reduzido do efluente sintético. O processo de eletrocoagulação, operando nessas condições envolve um custo total de 7,1 R$/m(3) e 5 R$/m(3) por metro cúbico para alumínio e ferro, respectivamente. Estes custos só incluem custo de energia e consumo dos eletrodos. A borra produzida foi de 2,23 kg/m(3) para alumínio e 2,76 kg/m(3) para o ferro. Finalmente, o consumo de energia foi de 4,15 kWh/m(3) e 3,72 kWh/m(3) para alumínio e ferro, respectivamente. Um tratamento de eletrocoagulação para um efluente oleoso sintético foi satisfatoriamente implementado do ponto de vista da redução destes parâmetros.
In the present work, electrocoagulation process (EC) with aluminum and iron as materials for anode and stainless steel as cathode, under different operational parameters, such as: initial concentration of oil, distance between electrodes, area-volume relation (SA/V) and current density, were examined in a systematic manner. Chemical oxygen demand (COD) and turbidity removals were selected as a performance criteria. Tests were carried out batch-wise in an electrochemical cell (5.1 liter) with synthetic wastewater and with magnetic stirring (150 rpm); the current density and SA/V relation were found to be the most significant parameters, an increase of theses notably reduces the electrocoagulation required time for the treatment. The results have shown that electrocoagulation, using both kind of materials (Fe/Al), successfully removes the COD and turbidity in experimental conditions such as: the current density, 9.4 mA/cm(2), distance between electrodes, 10 mm; SA/V relation, 30.35 m(2)/m(3) and 30 minutes of operation . Removal efficiencies over 99% and 98.3% were measured for COD and turbidity, using anodes of aluminum. Likewise 94.8% of COD and 98.5% of turbidity were removed from synthetic wastewater, using anode of iron. Electrocoagulation process operated under theses conditions involves a total cost of 7.1 R$/m(3) for aluminum and 5 R$/m(3) for iron per meter cubic of treated wastewater. These costs only include energy cost and electrode consumptions. The sludge produced after electrocoagulation treatment was 2.23 kg/m(3) for aluminum and 2.76 kg/m(3) for iron, and the power requirements were 4.15 kWh/m(3) and 3.72 kWh/m(3) for aluminum and iron. An electrocoagulation treatment of a synthetic wastewater was successfully implemented from removal efficiency point of view.
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Kuokkanen, V. (Ville). "Utilization of electrocoagulation for water and wastewater treatment and nutrient recovery:techno-economic studies." Doctoral thesis, Oulun yliopisto, 2016. http://urn.fi/urn:isbn:9789526211084.
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Abstract Electrocoagulation (EC) is an emerging technology that combines the functions and advantages of conventional coagulation, flotation, and electrochemistry in water and wastewater treatment. The aims of this work included doing an updated literary review of recent feasible applications of EC, which were found to be plentiful. Since the economic and practical operational key figures related to EC haven’t been extensively mapped out before, this was a prime objective of this part of the work. The aim of the next part of this work was to find new feasible applications for EC in the treatment of water and wastewater. The studied wastewaters included bio- and synthetic oil-in-water emulsions, various industrial nutrient-containing wastewaters, and peat bog drainage water containing humic substances (an interesting and topical problem, especially in Finland). These studies proved the feasibility of EC. In addition, larger-scale experiments were also conducted successfully, thus proving the scalability of the EC process. Extensive economic analyses of the studied EC applications were also done. The operational costs and energy consumption of EC were found to be very low—typically about 0.1–1.0 €/m3 and 0.4–4.0 kWh/m3. It has been forecasted that in the future there will be a shortage of virgin phosphorus. Therefore, another essential purpose of this work was to conduct a preliminary study on the feasibility of using EC for nutrient (especially phosphorus, but also nitrogen) removal and recovery from different types of real wastewater. Specifically, it may be possible to use EC sludges containing notable amounts of phosphorus and nitrogen as additives in granulated bio ash-based fertilizer products for various applications. This is a novel idea and a “hot topic” in the waste utilization sector and in circular and bioeconomyTiivistelmä Elektrokoagulaatio (electrocoagulation, EC) on nosteessa oleva teknologia, joka yhdistää perinteisen koagulaation, flotaation ja sähkökemian hyödyt ja mahdollisuudet vesien ja jätevesien käsittelyssä. Tämän työn ensimmäisenä tavoitteena oli laatia kirjallisuuskatsaus EC:n viimeaikaisista käyttökelpoisista sovelluksista, joita löytyi runsaasti. Koska EC:n toiminnallisia ja taloudellisia avainlukuja ei ole kartoitettu kattavasti aiemmin, tämän tekeminen oli tämän osion tärkein tavoite. Väitöstyön seuraavana tavoitteena oli löytää uusia sovellutuksia EC:lle vesien ja jätevesien käsittelyssä. Tutkittuja vesiä olivat bio- ja synteettisistä öljyistä valmistetut öljy-vesiemulsiot, erilaiset teolliset ravinnepitoiset jätevedet ja humusainepitoiset turvesoiden valumavedet (kiinnostava ja ajankohtainen ongelma, erityisesti Suomessa). EC todettiin käyttökelpoiseksi teknologiaksi näissä kokeissa. Suuremman skaalan kokeilla todistettiin lisäksi EC-prosessin skaalautuvuus. Lisäksi, em. EC-sovellutuksista suoritettiin kattavat taloudelliset analyysit. EC:n käyttökustannukset ja energiankulutus todettiin erittäin pieniksi, tyypillisesti ne olivat välillä 0.1–1.0 €/m3 ja 0.4–4.0 kWh/m3. On ennustettu, että tulevaisuudessa on pulaa neitseellisestä fosforista. Tästä johtuen eräs tämän työn keskeisistä tarkoituksista oli suorittaa alustavia kokeita liittyen EC:n käyttökelpoisuuteen ravinteiden (erityisesti fosfori, mutta myös typpi) poistossa ja talteenotossa aidoista jätevesistä. Erityisesti jatkossa voisi olla järkevää hyödyntää runsaasti fosforia ja typpeä sisältäviä EC-sakkoja lisäaineina rakeistetuissa biotuhkapohjaisissa lannoitteissa eri sovellutuksissa. Tämä idea on uusi ja on jo herättänyt suurta kiinnostusta mm. kierto- ja biotaloussektoreilla
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Lazenby, Lynn Anne. "Evaluation of selected new technologies for animal waste pollution control." Texas A&M University, 2006. http://hdl.handle.net/1969.1/4449.
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In 1998, two upper North Bosque River segments were designated as impaired
due to the nonpoint source (NPS) pollution of phosphorus (P) to these segments in the
watershed. As a result, two Total Maximum Daily Loads (TMDLs) were applied which
called for the reduction of annual loading and annual average soluble reactive P (Sol P)
concentrations by 50 %. This study was conducted to evaluate the efficacy of two
prospective new technologies, an Electrocoagulation (EC) system, and a Geotubeî
dewatering system to potentially aid the dairy farmers in meeting the goals set by the
TMDLs.
The EC system analyzed in this study used chemical pretreatment to coagulate
and separate solids in effluent pumped from the dairy lagoon; the liquid then flowed
over charged iron electrodes giving off ions that cause coagulation and precipitation of P
and other metals. Overall, the performance of the system was consistently highly
effective in reducing total phosphorus (TP) and Sol P, on average, reducing these
constituents by 96% and 99.6% respectively from the dairy lagoon effluent. However
this consistency did not hold for the rest of the analytes.
In the Geotubeî dewatering system geotextile tubes were utilized to dewater
dairy lagoon effluent. Results showed this system performed very well in filtering solids
from the dairy lagoon effluent, removing an average of 93.5 % of the total solids
between the two pumping and dewatering events of March and April. It was effective in
removing nutrients and metals as well. The average percent reduction of TP and Sol P
for the two events were very high at 97% and 85 % respectively.
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MEURIOT, SABINE. "Traitement palliatif par bicap des cancers obstructifs de l'oesophage et du cardia, evaluation clinique preliminaire chez 19 malades." Lille 2, 1988. http://www.theses.fr/1988LIL2M125.
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Hashim, K. S. "The innovative use of electrocoagulation-microwave techniques for the removal of pollutants from water." Thesis, Liverpool John Moores University, 2017. http://researchonline.ljmu.ac.uk/7041/.
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Electrocoagulation (EC) is an effective water and wastewater treatment technology; where the coagulants are generated in-situ by electrolytic oxidation of a sacrificial anode. In this technique, pollutant removal is done without adding chemicals; therefore, it remarkably reduces the sludge produced, and consequently reduces the cost of sludge handling. This method has been efficiently used to remove, up to 99%, of a wide range of pollutants such as heavy metals, oil, dyes, and fluoride. However, the EC technology still has a deficiency in the variety of reactor design, and its performance is highly influenced by the chemistry of the water being treated, especially the presence of organic matter (OM), as this inhibits heavy metal removal due to the formation OM-heavy metals complexes. The presence of heavy metals and OM in water resources is one of the most problematic pollutants in Hilla River, Babylon city, Iraq, which inhibits the application of the EC method in that area. Thus, the current study has been devoted to develop a new hybrid EC rector that can be applied to treat water drawn from Hilla River especially, and to treat water containing OM-heavy metals complexes. The aims of this study are therefore; firstly to examine the removal of heavy metals from drinking water in the presence of OM-heavy metal complexes using a new hybrid treatment method that utilises a combination of microwave-electrocoagulation (MW assisted-EC method). Secondly, to present a new configuration for an electrocoagulation reactor (FCER) that employs perforated plate flow columns (which are widely used in the chemical industry) to achieve water mixing, aeration, and temperature control processes. Additionally, the development of statistical models for the EC performance, recovery of hydrogen gas, and the removal of biological pollutants are other targets in the present project. Initially, the performance of the new flow column EC reactor (FCER) was validated in terms of water mixing efficiency, water aeration, and temperature controllability. The results were compared to those of traditional EC reactors. Then, the ability of the FCER to work as an EC unit was validated by treating different pollutants such as fluoride, nitrate, iron, and reactive black 5 (RB-5) dye from drinking water. Then, the ability of the new MW assisted-EC method to remove OM-heavy metal complexes was experimentally proved by treating synthetic water samples contain iron (Fe2+) ions and ethylenediaminetetraacetic acid (EDTA) (C10H16N2O8) (as organic matter). The results obtained showed that FCER achieved a complete water mixing efficiency, and increased the dissolved oxygen (DO) concentration by 110.6% within 10 min, and kept the temperature of water being treated within the range of 22-28 oC for 30 min of electrolysing. While the traditional reactors achieved water-mixing efficiency of 96.5%, increased the DO by 52.2%, and the temperature increased to about 32 oC over the same treatment period. Additionally, FCER was able to reduce fluoride, iron, nitrate, and RB-5 dye concentrations by 98%, 99.6%, 95.2%, 98.6%, respectively. In terms of OM-heavy metal complex removal (the novelty of the present work), the results obtained demonstrated that this novel method removes 92% of this refractory complex within 35 min of treatment at a power of 100 W, temperature of 100 oC, initial pH of 6, ID of 5 mm, and CD of 1.5 mA/cm2. While, the traditional treatment (EC only) removed only 69.6% of this complex under the same operating conditions. It is noteworthy to mention, the new MW assisted-EC method achieved 100% removal of culture-able activated sludge microorganisms ASM from drinking water, which could eliminate the need for costly separated biological treatment units. Statistically, empirical models were developed to reproduce the performance of FCER in terms of fluoride, nitrate, RB-5 dye, iron, and iron-EDTA complex removal. The R2 value for the models of fluoride, nitrate, RB-5 dye, iron, and iron-EDTA complex removal were, respectively, 0.823, 0.848, 0.798, 0.868, and 0.923. Economically, it has been found that the preliminary operating cost of the MW assisted-EC method is 0.628 US $/m3. Additionally, it has been found that the generated hydrogen gas from this new method could be used to reproduce about 2.82 kW/m3 of power, which is a promising amount of power on field scale plants. In conclusion, according to the obtained results, the new MW assisted-EC method is a safe promising alternative to the complicated, expensive, and time consuming traditional treatment methods, as it removes heavy metals in the presence of OM in a relatively short time without the need for chemical additives. Economically, the MW assisted-EC method reduces the need for separated biological treatment unit that require space, money, equipment, and time, because drinking water will be sterilised as it passes through the microwave field. The latter merit makes this new method a cost-effective alternative. Additionally, FCER reduces the need for external mixing and aeration devices that require extra power to work, which makes FCER a cost-effective alternative for traditional lab-scale EC units.
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Hansson, Henrik. "TREATMENT OF WASTEWATER GENERATED BY WOOD-BASED DRY INDUSTRIES: ADVANCED OXIDATION PROCESSES & ELECTROCOAGULATION." Doctoral thesis, Linnéuniversitetet, Institutionen för biologi och miljö (BOM), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:lnu:diva-36437.
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Wood is a material with an enormous number of applications. For decades, the development of wastewater treatment technologies tailored for the wood sector has focused on those industries that have water as an integral part of the industrial production, such as paper and pulp. However, there is a large and potentially growing sector that has been neglected, which is formed by industries in which water is not part of their production line, as for example, the wood floor and furniture industries (named wood-based dry industries). These industries still produces relatively low volumes of highly polluted wastewaters, with COD up to 30,000 mg/L, due to cleaning/washing procedure (named cleaning wastewaters). These cleaning wastewaters are often sent to the municipal wastewater treatment plant after dilution with potable water. Once there, recalcitrant pollutants are diluted and discharged into recipient water bodies or trapped in the municipal wastewater sludge. Another type of contaminated water these “dry industries” often generate in high volumes, and which is usually discharged with no previous treatment, is storm-water containing contaminants that have leached from large wood storage areas. The overall aim of this thesis was to increase the level of knowledge and competence and to present on-site wastewater treatment options for wood-based dry industries using the wood floor industry as a case-study, with a focus on combined treatment methods and solutions applicable to both the cleaning wastewater and storm-water. Among the treatment technologies investigated, electrocoagulation was studied both as a standalone treatment and combined with sorption using activated carbon. The combined treatment achieved a COD reduction of approximately 70%. Some advanced oxidation processes (AOP) were also studied: a COD reduction of approximately 70% was achieved by photo-Fenton, but the most successful AOP was ozone combined with UV light, were a COD reduction around 90% was achieved, with additional improvement in the biodegradability of the treated effluent. Ozone also proved to be effective in degrading organic compounds (approximately 70% COD reduction) and enhanced the biodegradability of the storm-water runoff from wood storage areas. The results have shown that the application of ozone can be considered an option for treatment of cleaning wastewaters and possibly for storm-water biodegradation enhancement.Trä är ett material med ett stort antal möjliga användningsområden. Inom träindustrin har utvecklingen av vattenbehandlingsmetoder varit inriktat på de branscher som har vatten som en del av produktionen, såsom papper- och massaindustrin. Men det finns en stor och potentiellt växande sektor inom träindustrin som har försummats, den utgörs av industrier som inte har vatten som en del av produktionen, t.ex. trägolv och trämöbel industrier. Trots detta så producerar dessa industrier fortfarande relativt kraftigt förorenade avloppsvatten med t.ex. COD-värden upp till 30000 mg/l men i relativt låga volymer. Dessa avloppsvatten uppkommer vid rengöring av maskiner och städning av lokaler, varefter de oftast efter utspädning med dricksvatten skickas till det kommunala reningsverket. Väl där späds det förorenade vattnet vidare ut med annat inkommande vatten men passerar dock till stor del obehandlat och släpps ut i mottagande vattendrag eller så fastnar föroreningarna i avloppsslamet. Dagvatten är en annan typ av förorenat vatten från dessa "torra industrier" som ofta genereras i stora volymer och innehåller föroreningar som lakats från de trämaterial som förvaras i de stora upplag som ofta förekommer vid denna typ av industrier. Det övergripande syftet med avhandlingen var att öka kunskapen och kompetensen för att kunna miljömässigt riktigt och ekonomiskt billigt behandla industriavloppsvatten lokalt på plats inom trävaruindustrin, genom att använda en trä-golvsindustri som fallstudie. Fokus lades på kombinerade behandlingsmetoder och lösningar som skulle kunna vara lämpliga både för industriavloppsvatten och dagvatten. Ett antal behandlingstekniker har undersökts; elektrokoagulering studerades både som en fristående behandling och i kombination med aktivt kol. Den kombinerade behandlingen gav en COD-reduktion på ungefär 70 %. Flera avancerade oxidationsprocesser (AOP) studerades också, och en COD-reduktion på cirka 70% uppnåddes med en kombination av UV-ljus och Fenton behandling. Den mest framgångsrika behandlingen var ozon i kombination med UV-ljus där en COD-reduktion runt 90 % uppnåddes varvid en avsevärd förbättring av den biologisk nedbrytbarhet på det behandlade avloppsvattenet erhölls. Ozon visade sig också vara effektivt för nedbrytning av organiska föreningar (ca 70% COD reduktion) och förbättrade den biologiska nedbrytbarheten av föroreningarna i dagvattnet från den studerade industrin. Resultaten har visat att ozon kan anses vara ett lämpligt alternativ för att behandla industriavloppsvatten inom trävarusektorn och möjligen för att öka den biologiska nedbrytbarheten av dagvattnet från dessa industrier
Integrated Approach for Handling of Industrial Wastewater and Stormwater
Triple Helix Collaboration on Industrial Water Conservation in Småland and the Islands
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Staicu, Lucian. "Production of colloidal biogenic elemental selenium and removal by different coagulation-flocculation approaches." Thesis, Paris Est, 2014. http://www.theses.fr/2014PEST1180/document.
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Le sélénium (Se) est un élément chalcogène avec un domaine de concentration étroit entre essentialité et toxicité. La toxicité est principalement liée à la spéciation chimique du Se qui évolue en fonction des conditions redox du milieu. Les formes oxyanioniques de Se, le sélénite (Se [IV], SeO32-) et le séléniate (Se [VI], SeO42-), sont solubles dans l'eau, biodisponibles et toxiques. En revanche, le sélénium élémentaire, Se(0), est insoluble et moins toxique. Néanmoins, les nanoparticules du Se(0) sont potentiellement dangereuses pour certains groupes des mollusques (comme les bivalves) et aussi pour les poissons. En outre, lorsque le Se(0) est rejeté dans les écosystèmes aquatiques, sa ré-oxydation jusqu'au sélénite et séléniate peut se produire. Le sélénium élémentaire d'origine biogénique Se(0) a été produit par la réduction de SeO42- dans des conditions anaérobies en utilisant un inoculum microbien mixte (boues granulaires) et par la réduction de SeO32- dans des conditions aérobies en utilisant une culture bactérienne pure (une nouvelle souche de Pseudomonas moraviensis identifiée et caractérisée pour la première fois dans cette thèse). Les deux types de Se(0) ont montré une forte stabilité colloïdale dans l'écart de pH variant de 2 à 12. La stabilité colloïdale est due à la charge négative (-15 mV à -30 mV) de la couche de biopolymère qui entoure Se(0) et à la taille nanométrique des particules de Se(0). La taille des particules de Se(0) produite par la boue anaérobie granulaire se situait entre 50 et 300 nm, avec une taille moyenne de 166 nm. A l'inverse, les nanoparticules de Se(0) produites par Pseudomonas moraviensis stanleyae sont caractérisées par un diamètre plus faible (~ 100 nm).Compte tenu des risques pour l'environnement engendrés par le relargage du Se(0) biogénique, des mesures appropriées doivent être mises en œuvre pour la séparation solide-liquide en utilisant une technologie efficace. Le potentiel de séparation solide-liquide de Se(0) généré a été évaluée par centrifugation, filtration, coagulation-floculation et électrocoagulation. Alors que toutes les approches présentent des rendements de séparation de Se(0) variables, l'électrocoagulation en utilisant des électrodes sacrificielles de fer a montré l'efficacité d'élimination le plus élevée (97%)Selenium (Se) is a chalcogen element with a narrow window between essentiality and toxicity. The toxicity is mainly related to the chemical speciation that Se undergoes under changing redox conditions. Se oxyanions, namely selenite (Se[IV], SeO32-) and selenate (Se[VI], SeO42-), are water-soluble, bioavailable and toxic. In contrast, elemental selenium, Se(0), is solid and less toxic. Nevertheless, Se(0) nanoparticles are potentially harmful as particulate Se(0) has been reported to be bioavailable to filter feeding mollusks (e.g. bivalves) and fish. Furthermore, Se(0) is prone to re-oxidation to toxic SeO32- and SeO42- when discharged into aquatic ecosystems. Biogenic Se(0) under investigation was produced by the reduction of Na2SeO4 under anaerobic conditions using a mixed bacterial inoculum (anaerobic granular sludge) and through the reduction of Na2SeO3 under aerobic conditions using a pure microbial culture (Pseudomonas moraviensis stanleyae, a novel strain identified and characterized for the first time herein). Both types of Se(0) showed strong colloidal stability within the 2-12 pH range. The colloidal stability is caused by the negatively charged (-15 mV to -30 mV) biopolymer layer covering biogenic Se(0) particles and by their nanometer size. The particle size of Se(0) produced by anaerobic granular sludge ranged between 50 and 300 nm, with an average size of 166 nm. Conversely, the Se(0) particles produced by Pseudomonas moraviensis stanleyae are characterized by a lower diameter (~ 100 nm).The solid-liquid separation potential of Se(0) was assessed by centrifugation, filtration, coagulation-flocculation and electrocoagulation. While all approaches can bring about Se(0) removal from suspension with various degrees of success, electrocoagulation using iron sacrificial electrodes showed the highest removal efficiency (97%). Because biogenic Se(0) is harmful to the environment, appropriate measures must be implemented for the solid-liquid separation using an efficient technology
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Peterson, Mark. "Electrodisinfection of Municipal Wastewater Effluent." ScholarWorks@UNO, 2005. http://scholarworks.uno.edu/td/294.
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To avoid the spread of disease from sewage treatment effluents, pathogenic microorganisms present must be destroyed by one or a combination of disinfection methods. Chlorine remains the predominant disinfectant used although it consumes considerable amounts of energy and has associated exposure risks from production, transportation and storage of this poisonous gas. In addition to bacteria and other objectionable microorganisms, color, suspended and colloidal solids also require removal from water for reuse. Aluminum and iron additions have been used to coagulate and remove non-settleable solids. By electrically dissolving aluminum to form solids-bridging aluminum hydroxide, the water itself can also be disinfected by the effects of electrical fields and its reactions to form disinfectant chemicals and direct destruction of microorganisms in the water. This research investigated the effects of electrical current, time, and chloride concentration on the electrochemical disinfection of sewage treatment plant effluent using aluminum electrodes to substitute for chlorine disinfection.
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McBeath, Sean T. "Pilot capacity iron electrocoagulation scale-up for natural organic matter removal for drinking water treatment." Thesis, University of British Columbia, 2017. http://hdl.handle.net/2429/60562.
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Canadian remote communities are most often those who are affected by poor water quality and boil water advisories. A major issue is the applicability of traditional water treatment technologies to unconventional applications (small-scale and inaccessible communities). Their inaccessibility presents difficulties for supplying needed chemicals involved in traditional treatment processes such as coagulations and flocculation. Electrocoagulation (EC), an electrochemical process producing coagulant chemicals on-site and on-demand, may be an alternative technology to traditional coagulation suitable for small and remote communities. The following work investigated a continuous iron EC process for natural organic matter (NOM) removal. EC experiments were undertaken in the laboratory at 1.35 and 5 LPM, using synthetic surface water, monitoring the effect of flocculation, metal loading (ML), current density and inter-electrode gap. At both flow rates, flocculation was found to have no effect on the reduction of DOC or UV-abs-254. ML was found to have the greatest effect on both DOC and UV-abs-254 reductions, where the highest ML tested yielded reductions >90% and >60%, respectively. Increases in UV-abs-254 at low ML were found to be due to dissolved residual iron. It was determined that humic acid and chloride functioned as ligands and increased the solubility of iron. Operations were scaled-up to 10 LPM and integrated into a water treatment plant in the community of Van Anda, using raw surface water. Average DOC and UV-abs-254 reductions at the greatest ML were 37.2±4.2% and 54.7±0.9%, respectively. EC was found to have low energy requirements at a pilot-scale, whereby 0.480-0.621 kWh per cubic meter of water treated was required to operate at the conditions that yielded the greatest NOM reductions. Finally, an investigation to determine the current density distribution was undertaken. Current distribution results yielded increased current uniformity with the increase of the inter-electrode gap. This increased uniformity can be attributed to the water velocity profiles in the reactor. Through computational fluid dynamic (CFD) models, it was demonstrated that fluid flow uniformity also increased with an increasing inter-electrode gap. Regions of the electrode that were observed to be occupied by high fluid velocity were also areas yielding greater current density.Applied Science, Faculty of
Chemical and Biological Engineering, Department of
Graduate
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Jackson, Ricardo Rodriguez Silva [Verfasser]. "Electrocoagulation Removal of Heavy Metals from Industrial Wastewater in Continuous Flow / Rodriguez Silva Jackson Ricardo." Aachen : Shaker, 2019. http://d-nb.info/1188550721/34.
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Gulsun, Kilic Mehtap. "A Parametric Comparative Study Of Electrocoagulation And Coagulation Of Aqueous Suspensions Of Kaolinite And Quartz Powders." Phd thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/12611458/index.pdf.
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Mineral treatment processes generally produce wastewaters containing ultrafine and colloidal particles that cause pollution upon their discharge into environment. It is essential that they should be removed from the wastewater before discharge. This study was undertaken by using synthetic turbid systems containing kaolinite and quartz particles in water with the amount of 0.20 g/L and 0.32 g/L, respectively. Removal of the turbidity was tried in two wayselectrocoagulation with aluminum anode and conventional coagulation with aluminum sulfate. Several key parameters affecting the efficiency of electrocoagulation and coagulation were investigated with laboratory scale experiments in search of optimal parameter values. Optimal values of the parameters were determined on the basis of the efficiency of turbidity removal from ultrafine suspensions. The parameters investigated in the study were suspension pH, electrical potential, current density, electrocoagulation time, and aluminum dosage. This study was also performed to compare electrocoagulation and conventional coagulation regarding the pH ranges under investigation and coagulant dosages applied. A comparison between electrocoagulation and coagulation was made on the basis of total dissolved aluminum, revealing that electrocoagulation and coagulation were equally effective at the same aluminum dosage for the removal of ultrafine particles from suspensions. Coagulation was more effective in a wider pH range (pH 5-8) than electrocoagulation, which yielded optimum effectiveness in a relatively narrower pH range around 9. In both methods, these pH values corresponded to near-zero zeta potentials of coagulated kaolinite and quartz particles. The mechanism for both coagulation methods was aggregation through charge neutralization and/or enmeshment in aluminum hydroxide precipitates. Furthermore, the experimental results confirmed that electrocoagulation could display some pH buffering capacity. The kinetics of electrocoagulation was very fast (<
10 min) in approaching a residual turbidity, which could be modeled with a second-order rate equation.
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Valdivia, Lefort Patricio. "Design of an Efficient Harvester and Dewater Mechanism for Microalgae." Diss., The University of Arizona, 2013. http://hdl.handle.net/10150/306344.
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Microalgae have now been widely considered as a promising bio-energy feedstock. The current microalgae harvesting methods used, such as centrifugation, sedimentation and flocculation, have been shown to be effective but are costly, representing between 35 % to 50 % of the total production cost. The aims of this study were: (1) to investigate the effectiveness of two electrocoagulation processes, electroflocculation and electroflotation, as algae pre-harvesting processes; and (2) to design, test and optimize a cost-effective and efficient filtration-based harvesting mechanism for micrioalgae. The principal results of the study showed that: (1) The mean final concentration for electroflocculation of 17.94 gL⁻¹ significantly exceeded (p = 0.0416) that for electroflotation of 9.51 gL⁻¹, indicating electroflocculation to be the more effective process; (2) Microscope images of the algae showed that, for the level of power applied (1 A, 40 V max), electrocoagulation did not appear to have produced any effect on the algae that was significantly different from that by centrifugation and that neither method appeared to have caused any significant cell wall damage or rupture; (3) The most effective configuration for the harvester prototype -- resulting in higher throughput rate (0.303 gh⁻¹), higher efficiency (233.33 gL⁻¹), as well as a lower energy consumption (143.46 kWhm⁻³) -- corresponded with higher concentration of the incoming biomass (21.5 gL⁻¹), lower belt velocity (0.05 ms⁻¹), higher inclination angle (25°) and lower pressure (0 Psi); and (4) The total energy consumption for the harvester prototype, when combined with a preceding pre-harvesting process, of 4.95 kWhm⁻³ was comparable to those reported by others for filtration-based harvesting. The new efficient harvesting mechanism proposed showed significant potential in successfully reducing algae production cost and make biofuels from microalgae economically feasible in the mid to long term in view of the prototype having achieved high output biomass concentration, low energy consumption per unit volume, high throughput rate, and facility of implementation.
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Baudequin, Clément. "Conception d'une unité mobile pour le post-traitement d'eau utilisée pendant des opérations d'extinction d'incendie." Thesis, Châtenay-Malabry, Ecole centrale de Paris, 2011. http://www.theses.fr/2011ECAP0045/document.
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L’extinction de feux de liquides inflammables sur des installations industrielles telles que les dépôts de carburant ou les raffineries entraîne l'utilisation de milliers de mètres cubes d'eau, composé majeur des mousses anti-incendie. Ces dernières contiennent généralement des tensioactifs hydrocarbonés ainsi que des tensioactifs fluorés qui se retrouvent dans les eaux d'extinction, ainsi que les suies et les restes de solvants. Les tensioactifs fluorés jouent un rôle clé dans l'efficacité des mousses anti-incendie en raison de leur nature chimique particulière. En raison de la présence des tensioactifs fluorés, le traitement actuel de l'eau d'extinction d'incendie est l'incinération dans des incinérateurs haute température et résistant aux halogènes. Les tensioactifs sont des composés amphiphiles qui ont comme propriétés d'abaisser la tension superficielle de l'eau et de former des agrégats en solution : les micelles. Les tensioactifs peuvent également s'adsorber aux interfaces ainsi qu'aux surfaces solides, et éventuellement y former des agrégats de surface, analogues aux micelles en solution. L’objectif industriel de la présente thèse est de proposer une unité mobile de traitement de ces eaux afin de concentrer les composés fluorés et limiter les volumes à incinérer. Les critères de sélection des procédés que nous avons retenus sont les suivants : compacité, peu ou pas de produits chimiques ou solides nécessaires. L’objectif scientifique de ce travail est de mieux comprendre le comportement de ces composés au cours des procédés d’électrocoagulation/filtration et d’osmose inverse. Des essais préliminaires ont été réalisés et ont permis de choisir les procédés suivant : l'électrocoagulation couplée à la filtration comme prétraitement pour séparer les particules en suspension et les traces d’émulsions éventuelles de la phase aqueuse et l'osmose inverse comme traitement pour concentrer les tensioactifs fluorés. A l'échelle du laboratoire, l'électrocoagulation, permettant le retrait de la matière en suspension, a été optimisée pour des eaux d'extinction d'incendie pilotes et un mécanisme a été proposé. L'efficacité de ce procédé a ensuite été vérifiée sur un pilote industriel. L'osmose inverse d'eaux d'extinction d'incendie pilotes pré-traitées par électrocoagulation/filtration a montré de forts taux de rétention du tensioactif fluoré. Une comparaison de différents matériaux membranaires a été réalisée sur un module d’osmose inverse plan avec des solutions modèles. Des essais de filtration de longue durée, à l’échelle pilote, ont permis de suivre l’évolution de la rétention des tensioactifs et du flux de perméat. Ces données ont été utilisées pour réaliser le dimensionnement d’une unité mobile de post traitement d’eau d’extinction d’incendie. Les perspectives de ce travail sont les suivantes : La prise en charge de la réalisation d’une unité mobile devrait être menée par un partenaire de DuPont de Nemours qu’il reste à identifier. L’étude sur la modification de l’état de surface des membranes est poursuivie dans le cadre d’une nouvelle thèse et permettra à terme de mieux choisir les conditions opératoires de filtration et de nettoyage au cours des procédés membranaires et ainsi d’améliorer les performances du procédéExtinguishment of large solvent fire leads to the production of fire fighting water, which are collected thanks to the design of industrial infrastructures. Depending on the nature of the firefighting foam used, the resulting water may require the removal of fluorinated surfactants potentially present. After decantation of the organic phase, fire fighting waters essentially contain surfactants. Surfactants are amphiphilic chemicals having the ability to lower both interfacial and surface tensions by adsorbing in an oriented fashion at interface. Surfactant can form micellar aggregates in solution and on interfaces under certain conditions, and have a pronounced influence on interfacial phenomena. Hence, before considering any water treatment process, interfacial science and surfactant were introduced. This work has a dual purpose. The industrial purpose is to provide an economically viable alternative to water incineration. The foreseen unit will have to be mobile and able to extract fluorinated surfactants from water at a rate of 1-4.5 m3h-1 (20,000 m3 in 4-6 months). The scientific purpose of this work is the study of the behavior of surfactants in the context of water treatment processes. The state of the art of relevant water treatment processes and an experimental screening with real firefighting water permitted to identify two steps as likely to fit the constraints of a mobile unit: electrocoagulationfiltration coupled with reverse osmosis. The electrocoagulation process followed by filtration was applied to pilot, model and industrial firefighting waters. This process was found to remove efficiently the unwanted turbidity from pilot firefighting waters. Current knowledge about the separation mechanisms of small organic molecules in reverse osmosis has been reviewed, and rejection as well as flux decline were related to membrane, solution, and solute properties. Polyamide and cellulose acetate membrane materials were screened in a flat sheet cell. The stabilities of rejection and flux decline were confirmed during longer tests (several days) on an industrial pilot with the most appropriate membrane. A final design study confirmed the possibility to combine electrocoagulation-filtration and reverse osmosis to treat firefighting waters
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Dubrawski, Kristian Lukas. "Reactor design parameters, in-situ speciation identification, and potential balance modeling for natural organic matter removal by electrocoagulation." Thesis, University of British Columbia, 2013. http://hdl.handle.net/2429/44132.
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Electrocoagulation (EC), a disruptive “green” technology, was investigated for the removal of natural organic matter (NOM) from drinking water sources. Three anode materials (aluminum, zinc, and iron) and three NOM sources (Suwannee, Nordic, and a local source) were investigated. After one minute of process time, dissolved organic carbon (DOC) reduction was approximately 70-80%. High performance size exclusion chromatography (HPSEC) fractionation showed reductions mostly in the larger apparent molecular weight (AMW) fraction of NOM, from 76% of NOM > 1450 Da initially to approximately 40% after EC. For iron EC, significant EC design variables were investigated, including: current density (i) (2.43-26.8 mA/cm²), and charge loading rate (CLR) (100 to 1000 C/L/min). Optimum NOM removal was found at i ~10 mA/cm² and lower CLR. In-situ identification of iron speciation in EC investigated the impact of i and CLR on speciation and NOM removal from a local natural source. Low i and intermediate CLR increased bulk pH and reduced bulk dissolved oxygen (DO), where green rust (GR) was identified in-situ for the first time in EC by Raman spectroscopy. Further oxidation at higher i and CLR led to magnetite (Fe₃O₄) formation, while all other conditions led to increased DO and/or increased pH, with subsequent identification of only orange lepidocrocite (γ-FeOOH). GR showed the marginally higher NOM DOC and AMW fraction reductions. In synthetic water, differing operating parameters led to differences in φ and iron speciation, characterized by in-situ Raman spectroscopy, aqueous XRD, SEM, and cryo-TEM. High i in the presence of pitting promoters led to φ near unity where a GR intermediate was seen, and an end product of Fe₃O₄. A mechanism scheme summarizing EC speciation is proposed. A general model relating cell potential and current was developed for parallel plate continuous EC, relying only on geometric and tabulated variable inputs. For the model, the anode and cathode were vertically divided into n equipotential segments. Potential and energy balances were simultaneously solved for each vertical segment iteratively. Model results were in good agreement with experimental data, mean relative deviation was 9% for a low flow rate, narrow electrode gap, and polished electrodes.
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de, Farias Lima Flávia [Verfasser], Peter [Gutachter] Krebs, Stefan [Gutachter] Stolte, and Reza Mohammad [Gutachter] Malayeri. "Oilfield produced water treatment with electrocoagulation / Flávia de Farias Lima ; Gutachter: Peter Krebs, Stefan Stolte, Reza Mohammad Malayeri." Dresden : Technische Universität Dresden, 2019. http://d-nb.info/1226942407/34.
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Willfors, Andreas. "Local Treatment of Water and Sludge Containing Oil in Sweden." Thesis, Mittuniversitetet, Avdelningen för ekoteknik och hållbart byggande, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:miun:diva-25146.
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Due to several reasons, treatment methods for a certain waste are oftennot available locally in the waste handling and management industry. This is especially true for regions which are not densely populated. This requires transports, the majority of which consumes fossil fuel. To avoid this, local waste treatment methods need to be developed. In this work it is investigated how treatment of one hazardous waste is done; water and sludge containing oil. Based on sustainability criteria three novel methods are presented that can be conducted locally; mycoremediation, phytoremediation and electrocoagulation. The methods are evaluated in a case study of a recycling company. Mycoremediation and electrocoagulation were found to be suitable in the case study, as long as some criteria are fulfilled. In addition it is shown what barriers exist in law, policies and practices that hinder local treatment of water and sludge containing oil.
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Simpson, Jessica R. "Effect of Cell Wall Destruction on Anaerobic Digestion of Algal Biomass." ScholarWorks@UNO, 2017. https://scholarworks.uno.edu/td/2433.
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Research was conducted using algal biomass obtained from the surface of a secondary clarifier at Bridge City Wastewater Treatment Plant and subsequently sent through an electrochemical (EC) batch reactor at various concentrations. The first objective was to achieve maximum cell wall destruction electrochemically using the EC batch reactor and determine the optimal detention time and voltage/current relationship at which this occurred. The second objective was to subject two algal mediums to anaerobic digestion: the algal medium without electrochemical disinfection and the algal medium after disinfection. Every three days, for 12 days, total solids were measured from each apparatus to determine if cell destruction increased, decreased or did not change the consumption rate of algae by anaerobic bacteria. The consumption rate of algae is directly proportional to the production of methane, which can be used as a source of biofuel.
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Cook, Monica Mion. "Endocrine-Disrupting Compounds: Measurement in Tampa Bay, Removal from Sewage and Development of an Estrogen Receptor Model." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5861.
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The significance of endocrine-disrupting compounds (EDCs) in the environment has only recently come to the forefront of scientific research, policy debates, water utilities management and public awareness. EDCs have the ability to interfere with the normal functioning of the endocrine system of humans and other animals. Numerous chemicals are included in the class of compounds known as EDCs, and exposure is widespread. These compounds are found in a variety of environmental matrices (e.g., marine and freshwater systems, sediment, soil), transported there primarily through sewage effluent discharge and recycling of sewage sludge for topical fertilizer use. This transport to the environment serves as the primary route of exposure for aquatic and terrestrial organisms living there. Furthermore, these compounds are also found in consumer products, food and drinking water--which serve as the exposure source for human beings. Multiple examples of endocrine disruption have been documented in humans and animals, and certain EDCs have been implicated in each case. The future of public and environmental health will depend upon mitigating the effects of these chemicals.
This purpose of this dissertation is to provide an initial understanding of EDC occurrence in the Tampa Bay region of south Florida, and to complement the existing body of EDC research with regards to marine systems. It focuses on estrogenic EDCs, specific compounds which target the estrogen axis of the endocrine system. Six estrogenic EDCs were chosen based on their documented prevalence in the environment, prevalence in sewage, and for their suspected endocrine-disrupting effects: estrone, 17β-estradiol, estriol, 17α-ethinylestradiol, bisphenol-A and nonylphenol. These compounds were verified to be amenable to and detectable by gas chromatography-mass spectrometry analysis.
Since the occurrence of EDCs in aquatic environments of the Tampa Bay region had not been previously characterized, the initial phase of the research focused on quantification of the six estrogenic EDCs in Tampa Bay area water, sediment, and sewage influent and effluent. All targeted EDCs were present in 89% of sewage samples, while 100% of the samples contained at least one or more EDCs. The concentrations of EDCs in marine aqueous and sediment samples tended to decrease with increasing distance from the wastewater treatment plant discharge site. The ubiquitous presence of these estrogenic EDCs in the Tampa Bay area is cause for concern with respect to endocrine disruption in local terrestrial and aquatic wildlife. Since the Tampa Bay region is home to a wide variety of marine organisms, constant exposure to EDCs could result in ecosystem-level effects, as these compounds can impair reproductive fitness and lead to other adverse health effects. This research also served to enlarge the existing scientific literature on EDC occurrence, as many marine and freshwater systems continue to be characterized globally.
The very basis for expecting to find EDCs in the Tampa Bay area had come from the fact that the main source of environmental contamination is typically the effluent discharge from area wastewater treatment plants. Conventional wastewater treatment plant processes are designed to reduce the amount of organic matter, pathogens and nutrients from the incoming influent. However, the processes are not as effective in removing micropollutants, including EDCs. These compounds notoriously evade traditional wastewater treatment technologies and are found even in tertiary-treated effluent. For this reason, the second phase of the research assessed an electro-chemical technique for the removal of the same six EDCs. The removal technique was tested on a laboratory scale and has a commercial-sized counterpart which can be integrated at the level of the wastewater treatment plant. In order to test the removal efficiency, samples of influent and tertiary-treated effluent were spiked with the six EDCs. The mean concentration of each EDC component was statistically lower after treatment (removal range = 42% - 98.2%), demonstrating the effectiveness of this electro-chemical process for EDC removal from both raw and treated sewage. The significance of the results lies in the fact that if this method is implemented, then future wastewater treatment plant effluent discharge (similar to that of the Tampa Bay region) could be less impacted by EDCs and therefore cleaner for the environment into which it is being discharged.
For the final phase of the research, the use of computational techniques to simulate human endogenous estrogen binding to its receptor was started as a foundation for future models to eventually predict endocrine-disrupting potential of different chemical compounds. We built an estradiol-human estrogen receptor model, and used molecular dynamic simulations to determine the binding free energy. The calculated total binding free energy of estradiol bound to the ligand binding domain of the human estrogen receptor was found to be -16.85 kcal/mol, which is in range of the experimental value of -12.40 kcal/mol. Humans are chronically exposed to low doses of EDCs every day, which makes endocrine disruption a considerable public health issue. Human exposure to EDCs is completely different from marine organism exposure, but the adverse effects are no less significant. The successful completion of this model serves as a platform for 1. Testing the human model against endocrine-disrupting compounds, 2. Subsequent models that will be developed for different species, including marine species important to Tampa Bay.
Substantial data exist regarding the exposures and health risks associated with EDCs in humans and wildlife on a global scale. As the pressing issues of climate change and carbon emissions are at the top of the list of environmental concerns, it is important to note that mitigating the effects of EDCs should not be overlooked and will be an important responsibility of regulatory agencies in the near future.
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Lian, Ie Tjie [UNESP]. "A eletrocoagulação na terapêutica das lesões intra-epiteliais escamosas de alto grau do colo uterino." Universidade Estadual Paulista (UNESP), 2001. http://hdl.handle.net/11449/93106.
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lian_it_me_botfm.pdf: 1463220 bytes, checksum: eb4ee40b710b15dce35aeb229f8308a2 (MD5)Analisar a eficácia da eletrocoagulação, como terapêutica nas pacientes portadoras de lesão intra-epitelial escamosa de alto grau de colo uterino. Pacientes e métodos: Estudaram-se prospectivamente 116 pacientes portadoras de lesão intra-epitelial escamosa de alto grau do colo de útero, distribuídas aleatoriamente, com 49 pacientes no grupo de estudo e 67 pacientes no grupo controle. Ambos os grupos foram avaliados quanto à idade, coitarca, paridade, hábito de tabagismo, número de parceiros sexuais, uso de drogas, presença ou antecedente de lesão condilomatosa vulvar, raça e escolaridade. Essas variáveis apresentaram-se homogêneas em ambos os grupos. Todas as pacientes do grupo de estudo e do grupo-controle foram submetidas a colposcopia...
Analyzing the efficiency of electrocoagulation as therapeutics in patients carrying high degree squamous intraepithelial lesion of the uterine cervix. Patients and methods: 116 patients carrying high risk intraepithelial lesion of the uterine cervix were prospectively studied, randomly distributed, being 49 patients in the study-group and 67 patients in the control-group. Both groups were evaluated according to age, first copulation, parity, smoking habits, number of sex partners, drug usage, presence or previous condylomatous lesion of the vulva, race and schooling. Such variables were found to be even in both groups. All patients from both groups were submitted to colposcopy, oncological cytology and biopsy of the uterine cervix. The study- group patients were treated with electrocoagulation of the uterine cervix and later submitted to conization after two months. The control-group patients underwent conization only. To assess the significance of the resuts, qui-square and Kappa agreement test were used. Results: In the study-group, electrocoagulation of the uterine cervix caused regression of the lesion in 73,5% of the cases, 20,4% remained unchanged, and there was progression... (Complete abstract click electronic access below)
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Sharma, Swati. "Treatment of Industrial Wastewater Derived Organic Pollutants Using Electrochemical Methods Through Optimization of Operation Parameters." Diss., North Dakota State University, 2019. https://hdl.handle.net/10365/29268.
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Industrial operations produce a notable amount of wastewaters with high concentration of chemical oxygen demand (COD), mostly consisting of organic carbon compounds. The treatment performance of electrochemical methods for organic removal and the effects of process parameters are the subject of this research.
Three research tasks were performed. The first task was the removal of organic pollutants from three different industrial wastewaters using two different electrochemical methods; combined electrocoagulation + electrooxidation (EC+EO) and b) electrochemical peroxidation (ECP). Using only EC process was found to be significantly successful in removing suspended and colloidal pollutants and could remove more than 90% COD and 80% of TOC. The study showed that combined EC+EO process had better removal capability compared to ECP when operated under similar process conditions.
The second task was to study the effect of the process parameters; pH, H2O2 dosage, current density, and operation time; and to optimize and estimate the best treatment conditions for the methods using Box-Behnken Design (BBD). For sugar beet wastewater, the results showed that EO could remove 75% of organics at optimum conditions of pH 5.3; current density of 48.5 mA/cm2; and operation time of 393 min. The canola oil refinery wastewater achieved more than 90% pollutant removal when the conditions were optimized at pH 5.8 – 6 with applied current density of 9.2 mA cm-2¬ run for nearly 300 min. The rate of degradation of the wastewater derived organic pollutants followed a first order kinetics for all the wastewaters investigated and the models were validated for goodness of fit with high R2.
The final task was to compare treatment efficiency between the electrochemical processes. Based on the energy consumed and the performance efficiency to remove COD, sCOD, TOC and DOC in the three different wastewaters studied, EC+EO process was found suitable for the treatment of canola and sunflower oil wastewater. On the other hand, from the model prediction and the experiments conducted, EO resulted in better removal capability compared to ECP. Also, the consumption of energy by ECP was comparatively higher than EO process while taking longer time of operation for significant removal.North Dakota Water Resources Research Institute; North Dakota Agricultural Experimental Station; Frank Bain Agricultural Scholarship
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Popovic, Ivan [Verfasser], Markus [Gutachter] Thewes, and Marc [Gutachter] Wichern. "Electrocoagulation in the separation process of used bentonite suspensions / Ivan Popovic ; Gutachter: Markus Thewes, Marc Wichern ; Fakultät für Bau- und Umweltingenieurwissenschaften." Bochum : Ruhr-Universität Bochum, 2020. http://d-nb.info/1216333041/34.
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Zongo, Inoussa. "Étude expérimentale et théorique du procédé d'électrocoagulation : application au traitement de deux effluents textiles et d'un effluent simulé de tannerie." Thesis, Vandoeuvre-les-Nancy, INPL, 2009. http://www.theses.fr/2009INPL066N/document.
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L’électrocoagulation est une technique de traitement des eaux usées basée sur la dissolution d’anode sacrificielle de fer ou d’aluminium. Ces métaux se dissolvent sous formes de cations Fe2+ puis Fe3+ et Al3+ qui vont former des hydroxydes de métal qui entraînent par adsorption les impuretés de l’effluent en diminuant le potentiel Zêta de ces impuretés. Le réacteur électrochimique utilisé est constitué de deux électrodes métalliques (Fe ou Al) planes et parallèles qui laissent passer entre elles l’effluent à traiter. Des densités de courant de 50 à 200 A/m2 ont été appliquées pour traiter les trois effluents. L’un est un effluent directement issu d’une usine textile (effluent « usine »). Un second provient du flux d’entrée de la station d’épuration du site qui collecte les effluents de plusieurs usines (effluent « station »). Le troisième est un effluent artificiel de tannerie, créé en ajoutant 200 ppm de chrome VI à l’effluent « station ». Pour chaque expérience, la densité de courant et le temps de traitement vont déterminer la charge électrique et la concentration en métal dissous atteinte. L’influence de ces quatre paramètres sur l’élimination de la DCO, de l’absorbance, de la turbidité, du COT et du chrome hexavalent a été étudiée. L’évolution au cours du temps d’autres paramètres de l’EC tels que le pH, la tension, le rendement faradique et la dissolution métallique ont été étudiés afin de comprendre leur rôle dans le procédé. Le traitement a permis d’avoir un abattement maximal de DCO de 82% et 80% pour l’effluent « station » traité respectivement avec les électrodes de fer et d’aluminium ; 75 et 67% pour l’effluent « usine » traité respectivement avec les électrodes de fer et d’aluminium. L’abattement du chrome est de 100% avec les électrodes de fer mais tombe à 70% avec celles en aluminium. Des modèles d’élimination de la DCO et de l’absorbance ont été établis pour chaque matériau d’électrode utilisé. Le modèle d’élimination du chrome VI a été établi à partir du traitement avec les électrodes de fer. Une étude de la spéciation des espèces a permis de déterminer les pH optimaux de coagulation-floculation pour chaque métal impliqué (Al, Fe, Cr). La compétitivité entre l’abattement de la pollution organique et du Chrome a aussi été étudiée pour chaque type d’électrodeElectrocoagulation (EC) is a water treatment technology that relies on the electrochemical sacrificial anodes (in Fe or Al) dissolution. This metal dissolve themselves in Al3+ and Fe2+ cations that later oxidise to Fe3+ ions. These cations form metal hydroxides that adsorb the impurities of the effluent while decreasing the zeta potential. The electrochemical reactor used consists on two plane parallel metal electrodes with recirculation of the effluent to be treated between them. Current densities from 50 to 200 A/m2 were imposed to treat each effluent. Three effluents were used in this study. The first one is an effluent sampled at the outlet of a textile plant (« plant »). The second one is a mixture of several effluents coming from different plant and collected at the inlet of the wastewater treatment (« treatment plant »). The last one is a wastewater tannery plant simulated by addition of 200 ppm Chromium VI in the treatment plant effluent. For each experience the current density and the time of treatment rule the electrical charge and the concentration in dissolved metal reached. The influence of these four parameters on the elimination of COD, absorbance, turbidity, COT and hexavalent chromium content has been studied. Parameters e.g. potential, faradic yield, metal dissolution and pH have also been continuously monitored to better understand their role on EC process. The results show that DCO abatement reached 80 and 82% for treatment plant effluent, respectively with iron and aluminium electrodes; and 75 and 67% for plant effluent, respectively with iron and aluminium electrodes. The chromium treatment yields 100 % abatement with Fe electrodes whereas it is only 70% using Al electrodes. Models have been developed for COD and absorbance removal for the two electrode materials. Model for chromium (VI) treatment has been established considering all reactions occurring for iron EC. Metal speciation study allowed us to determine the optimal pH of coagulation –flocculation for each metal involved in the treatment (Al, Fe, Cr). Competition between organic pollution removal and chromium elimination has been also investigated for each electrode material
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Pessoa, Germana de Paiva. "Estudo da RemoÃÃo de Cor de Efluente TÃxtil por EletrocoagulaÃÃo." Universidade Federal do CearÃ, 2008. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=1396.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoA cor dos efluentes tÃxteis oriunda das estruturas polimÃricas dos corantes à um problema para as indÃstrias tÃxteis. Dentre as tÃcnicas para o tratamento desse tipo de efluente, ressalta-se a eletrocoagulaÃÃo (EC), a qual consiste em uma tÃcnica fÃsico-quÃmica aplicada tanto para remoÃÃo de cor como para poluentes orgÃnicos. Neste trabalho, avaliaram-se, em sistema de batelada, trÃs etapas do processo EC na remoÃÃo de cor de corantes. Na primeira etapa (efluente sintÃtico e eletrodos de alumÃnio primÃrio) foi utilizado o corante reativo, Remazol Blue RR, onde verificou-se o efeito dos parÃmetros operacionais, tais como: densidade de corrente, o pH inicial da soluÃÃo, tempo de eletrÃlise, concentraÃÃo inicial do corante, condutividade da soluÃÃo, demanda quÃmica de oxigÃnio (DQO) e o consumo de energia, obtendo-se uma remoÃÃo de cor de 98% e 100%, em um tempo de tratamento de 20 e 40 minutos, respectivamente. Nas condiÃÃes operacionais otimizadas, foram obtidos 98% remoÃÃo de cor e 97% de DQO, sendo o custo do processo de R$ 2,62 por m3 de efluente tratado. Na segunda etapa (efluente sintÃtico e eletrodos de latinhas reciclÃveis), verificou-se uma remoÃÃo de cor de 90% e 95% para o tempo de tratamento de 20 e 30 minutos, respectivamente. Ressalta-se que, para o tempo de 20 minutos, o custo operacional foi de R$ 0,95, enquanto que, para 30 minutos foi de R$ 1,42 por m de efluente tratado. Na terceira etapa utilizou-se efluente tÃxtil real, proveniente da indÃstria BenatÃxtil localizada na cidade de Fortaleza - Cearà e eletrodo de alumÃnio primÃrio. O melhor resultado de remoÃÃo de cor foi de 77,63%, com diluiÃÃo de 5%, tempo de tratamento de 30 minutos e pH inicial 3,0. O custo energÃtico calculado para essa etapa foi de R$ 2,01 por m3 de efluente tratado. Nesse estudo foi possÃvel verificar que o processo de eletrocoagulaÃÃo pode ser eficiente na remoÃÃo de cor de um efluente sintÃtico constituÃdo por corantes, mas que, para o efluente tÃxtil real sem nenhum tratamento prÃvio faz-se necessÃrio a diluiÃÃo do mesmo, devido à alta concentraÃÃo do corante e elevada condutividade.
The textile effluent color resultant from dyes polymeric structures is a problem for textile industries. Amongst the treatment techniques for this type of effluent, it is emphasized the electrocoagulation (EC), which consists of a physicochemical technique applied for either color or organic pollutants removal. In this work, three stages of the EC process, in batch, for dye color removal were assessed. In the first stage (synthetic effluent and primary aluminum electrodes), the reactive dye Remazol Blue RR was used and the effect of operational parameters such as electric current density, initial solution pH, electrolysis time, initial dye concentration, solution conductivity, chemical oxygen demand (COD) and the energy consumption was verified, reaching a color removal of 98% and 100%, for the treatment time of 20 and 40 minutes, respectively. In the optimized operational conditions, 98% of color removal and 97 % of DQO removal were obtained, resulting a process cost of R$ 2,62 per m3 of treated effluent. In the second stage (synthetic effluent and electrodes made from cans), a color removal of 90% and 95%, for the treatment time of 20 and 30 minutes, was verified, respectively. It is important to mention that, for the time of 20 minutes, the operational cost was R$ 0,95, whereas, for 30 minutes, was R$ 1,42 per m3 of treated effluent. In the third stage, real textile effluent from BenatÃxtil, a textile industry located in Fortaleza city â CearÃ, and primary aluminum electrodes were used. The best result for color removal was 77,63%, with dilution of 5%, treatment time of 30 minutes and initial pH 3,0. The calculated energy cost for this stage was of R$ 2,01 per m3 of treated effluent. In this study it was possible to verify that the electrocoagulation process can be efficient in the color removal of a synthetic textile effluent composed of dyes, but, for the real textile effluent without a previous treatment, it is necessary to dilute it due to its high dye concentration and conductivity.
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Silva, Josà Pedro Varela da. "Tratamento de efluentes de tanques de piscicultura aplicando a tecnologia de eletrocoagulaÃÃo." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10754.
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CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel SuperiorPara a realizaÃÃo deste trabalho, foi utilizada a tÃcnica da eletrocoagulaÃÃo (EC) para o tratamento de efluente de piscicultura. Um reator de EC em escala de laboratÃrio, com capacidade de 1,5 L foi montado, utilizando um conjunto de quatro placas de eletrodos de alumÃnio, um agitador mecÃnico de alto torque microprocessado, fios condutores com garras de jacarà e uma fonte de tensÃo com potÃncia regulÃvel. Os eletrodos foram arranjados dentro da cÃlula eletrolÃtica de forma monopolar, em paralelo e a uma distÃncia de 11 mm. O efluente utilizado neste estudo foi coletado em tanques de piscicultura do centro de criaÃÃo de peixes do Departamento de Engenharia de Pesca da Universidade Federal do CearÃ. Para a determinaÃÃo da melhor condiÃÃo de operaÃÃo do reator, foi feito um planejamento experimental por intermÃdio do Software âStatgraficsâ, definindo, as variÃveis operacionais e os seus respetivos intervalos de variaÃÃo (pH inicial de 4 a 8, condutividade de 1000 a 4000 μS cm-1, tempo de eletrolise de 15 a 35 min., agitaÃÃo de 200 a 600 rpm e corrente de 1 a 2,5 A), que combinadas entre si totalizaram um total de 35 ensaios experimentais. Com base nos resultados obtidos por meio das anÃlises fÃsico-quÃmicas em laboratÃrio, pode-se afirmar que o pH inicial=8, condutividade=1000 μS cm-1, tempo=35 min., agitaÃÃo=200 rpm e corrente=2,5 A, sÃo as condiÃÃes Ãtimas de operaÃÃo do reator. Nestas condiÃÃes, alcanÃaram remoÃÃo de 84,95% para DQO, 98,06% para nitrito, 82,43% para nitrato, 98,05% para fÃsforo total e 95,32% para a turbidez, sendo o custo operacional de 4,59 R$/m3 de efluente tratado. Com base nos resultados obtidos, pode-se concluir que alguns dos parÃmetros analisados (pH, turbidez, temperatura, STD, nitrito, nitrato e fÃsforo total) estÃo de acordo com os padrÃes estabelecidos para Ãgua doce, classe 2, pela ResoluÃÃo CONAMA n 357/05, e de acordo com a ResoluÃÃo CONAMA n 430/2011 e a Portaria n 154/2002 da SEMACE (CE), para lanÃamento do efluente final nos corpos receptores. A tÃcnica de eletrocoagulaÃÃo alÃm de ser um mÃtodo alternativo, eficiente e promissor para tratamento de efluentes de piscicultura, tambÃm mostrou ser ecologicamente correto por dispensar o consumo elevado de reagentes,ao contrÃrio do que acontece no tratamento convencional.
For this work, we used the technique of electrocoagulation (EC) for the treatment of effluent from fish farms. An EC reactor at laboratory scale with a capacity of 1,5 L was assembled using a set of four plates of aluminum electrodes, a mechanical stirrer high torque microprocessor, wires with alligator clips and a voltage source with power adjustable. The electrodes were arranged inside of the electrolytic cell in a monopolar form, in parallel and at a distance of 11 mm. The effluent used in this study was collected in fishponds of fish breeding center of the Engineering Department of Fisheries, Federal University of CearÃ. To determine the best operating condition of the reactor, an experimental design was performed using the software "Statgrafics", defining the operational variables and their respective intervals (Initial pH 4 to 8, conductivity from 1000 to 4000 μS cm-1, electrolysis time 15 to 35 min., agitation 200-600 rpm and electrical current from 1 to 2,5 A), that combined together, performing a total of 35 runs. Based on the results obtained by means of physical-chemical analysis in the laboratory, it can be stated that the initial pH=8, conductivity=1000 μS cm-1, time=35 min., agitation=200 rpm and electrical current=2,5 A, are the optimal operating conditions of the reactor. Under these conditions, removal reached 84,95% for COD, 98,06% for nitrite, 82,43% for nitrate, 98,05% for total phosphorus and 95,32% for turbidity, resulting an operating cost of R$ 4,59 per m3 of treated effluent. Based on the results obtained, it can be concluded that some of the analyzed parameters (pH, turbidity, temperature, STD, nitrite, nitrate and total phosphorus) are in accordance with the standards established for fresh water, class 2, by CONAMA Resolution n 357/05, and according to CONAMA Resolution n 430/2011 and Decree n 154/2002 of SEMACE (CE), for release of the final effluent in the receiving water bodies. The technique of electrocoagulation besides being an alternative, efficient and promising for treating effluents from fish farming, also proved to be environmentally friendly for taking the high consumption of reagents, contrary to what happens in conventional treatment.
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Sun, Yuxia. "Colloidal and Electrochemical Aspects of Copper-CMP." Diss., The University of Arizona, 2007. http://hdl.handle.net/10150/194903.
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Copper based interconnects with low dielectric constant layers are currently used to increase interconnect densities and reduce interconnect time delays in integrated circuits. The technology used to develop copper interconnects involves Chemical Mechanical Planarization (CMP) of copper films deposited on low-k layers (silica or silica based films), which is carried out using slurries containing abrasive particles. One issue using such a structure is copper contamination over dielectric layers (SiO2 film), if not reduced, this contamination will cause current leakage. In this study, the conditions conducive to copper contamination onto SiO2 films during Cu-CMP process were studied, and a post-CMP cleaning technique was discussed based on experimental results. It was found that the adsorption of copper onto a silica surface is kinetically fast (< 0.5 minute). The amount of copper absorbed is pH and concentration dependent and affected by presence of H2O2, complexing agents, and copper corrosion inhibitor Benzotrazole. Based on de-sorption results, DI water alone was unable to reduce adsorbed copper to an acceptable level, especially for adsorption that takes place at a higher pH condition. The addition of complex agent, citric acid, proved effective in suppressing copper adsorption onto oxide silica during polishing or post-CMP cleaning by forming stable copper-CA complexes. Surface Complexation Modeling was used to simulate copper adsorption isotherms and predict the copper contamination levels on SiO2 surfaces.Another issue with the application of copper CMP is its environmental impact. CMP is a costly process due to its huge consumption of pure water and slurry. Additionally, Cu-CMP processing generates a waste stream containing certain amounts of copper and abrasive slurry particles. In this study, the separation technique electrocoagulation was investigated to remove both copper and abrasive slurry particles simultaneously. For effluent containing ~40 ppm dissolved copper, it was found that ~90% dissolved copper was removed from the waste streams through electroplating and in-situ chemical precipitation. The amount of copper removed through plating is impacted by membrane surface charge, type/amount of complexing agents, and solid content in the slurry suspension. The slurry particles can be removed ~90% within 2 hours of EC through multiple mechanisms.
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Maia, Liana Geisa Conrado. "Estudo do processo de eletrocoagulaÃÃo/floculaÃÃo aplicado ao polimento de efluente domÃstico." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13793.
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O presente trabalho propÃs uma alternativa de polimento de efluentes sanitÃrios por meio da tÃcnica deeletrocoagulaÃÃo/floculaÃÃo. O trabalho investigou a aplicaÃÃo desta tecnologia com dois conjuntos de eletrodos, alumÃnio e aÃo carbono,no polimento do efluente da lagoa de estabilizaÃÃo da estaÃÃo de tratamento de efluentes do Conjunto Nova MetrÃpole, localizada na cidade de Caucaia, CearÃ. Os estudos de aplicaÃÃo da tÃcnica para tratamento de efluentes foram feitos em nÃvel de bancada. Com o objetivo de avaliar a viabilidade tÃcnico-econÃmica da implantaÃÃo do polimento eletrolÃtico do efluente de lagoas de estabilizaÃÃo, foram conduzidos testes em cÃlulas eletrolÃticas de 4,0 L operando em batelada, variando-se algumas configuraÃÃes, tais como pH, velocidade de agitaÃÃo e concentraÃÃo de eletrÃlito. Com base na eficiÃncia de reduÃÃo de DQO foram determinadas as configuraÃÃes Ãtimas para o conjunto de eletrodos onde houve maior remoÃÃo de matÃria orgÃnicadurante os ensaios, a partir do delineamento experimental Box-Behnken. Observou-se que as configuraÃÃes Ãtimas para os eletrodos de aÃo carbono foram 7,91 de pH inicial, 210 rpm develocidade de agitaÃÃo e 0,5049 mg/L de NaCl de concentraÃÃo de eletrÃlito e 10 minutosde tempo de reaÃÃo. Nestas condiÃÃes foram obtidas remoÃÃes de DQO de69,20%, de DBO de 89,29 % e ainda fÃsforo total e coliformes totais de 100%, adequando o efluente ao lanÃamento em corpo receptor.This paper proposed a wastewater polishing alternative by electrocoagulation / flocculation technique. The study investigated the application of this technology with two sets of electrodes, aluminum and carbon steel, polish the effluent from the treatment plant of Nova MetrÃpole, located in Caucaia, CearÃ. The technique of application for wastewater treatment studies were carried out in bench level. In order to assess the technical and economic feasibility of the implementation of electrolytic polishing of wastewater stabilization ponds, tests were conducted in 4,0 L of electrolytic cells operating in batch, varying some settings, such as pH, stirring speed and the concentration of electrolyte. Based on COD reduction efficiency were determined the optimal settings for the set of electrodes where there was a greater removal of organic matter during the tests, from the Box-Behnken experimental design. It was noted that the optimal settings for the carbon steel electrodes were the initial pH 7,91, 210 rpm stirring speed and 0,5049 mg/L de NaCl electrolyte concentration, and 10 minutes reaction time. Under these conditions COD removals were obtained from 69,20% of BOD 89,29% and total phosphorus and total coliforms 100%, adjusting the effluent to launch in receiving body.
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Labanowski, Jérôme. "Matière organique naturelle et anthropique : vers une meilleure compréhension de sa réactivité et de sa caractérisation." Limoges, 2004. http://aurore.unilim.fr/theses/nxfile/default/9d25021a-654e-427c-bdac-a3e8527731cd/blobholder:0/2004LIMO0031.pdf.
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Cette étude s’est intéressée à caractériser la Matière Organique (MO) d’un lixiviat, MO qui joue un rôle majeur dans les processus biogéochimiques et dans la mobilité des polluants au sein des décharges. Des protocoles de fractionnement par résines XAD ont été mis en place afin d’étudier et de comparer la répartition des éléments carbonés, azotés et de l’oxydabilité de cette MO avec diverses matières organiques de milieux naturels terrestres (sol, tourbe) et aquatiques (eau de surface et eau souterraine). Une identification des éléments de base de la MO du lixiviat (fractions extraites) a été réalisée par pyrolyse CG/SM après dérivation au TMAH. La matière organique la plus hydrophile a en outre fait l’objet d’une nouvelle procédure de conditionnement à la pyrolyse, basée sur la fixation sur une argile catalytique. Divers protocoles de mesure de la biodégradabilité ont été développés et appliqués sur des fractions extraites permettant une caractérisation originale de la MO au travers de sa réactivité biochimique. Une autre approche de caractérisation a consisté à étudier la réactivité chimique de la MO du lixiviat en utilisant des procédés de traitement que sont la coagulation-floculation et l’électrocoagulationThis study was interested to characterise Organic Matter (OM) from a leachate, OM which plays a major role within landfills. Fractionation protocols by XAD resins were set up in order to compare the distribution of carbon-contained and nitrogen-contained elements and of the oxydability of this OM with various OM of terrestrial (soil, peat) and aquatic (surface water and groundwater) natural environments The basic elements of the leachate OM were identified by pyrolysis GC/MS after TMAH derivation. The most hydrophilic OM was the subject of a procedure of conditioning to pyrolysis, based on a fixation on a catalytic clay. Biodegradability tests were developed for an original characterisation of OM based on its biochemical reactivity. Another approach of characterisation consisted in studying the chemical reactivity of OM by using treatment processes like coagulation-flocculation and electrocoagulation
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Fayad, Nidal. "Mise en oeuvre du procédé d'électrocoagulation pour le traitement des eaux usées et pour la séparation et la purification de milieux biologiques." Thesis, Université Clermont Auvergne (2017-2020), 2017. http://www.theses.fr/2017CLFAC024/document.
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L'électrocoagulation (EC) est une méthode électrochimique non spécifique couramment utilisée pour le traitement de l'eau et des eaux usées. Dans ce travail, l’EC est d'abord étudiée comme une technique classique de traitement des eaux usées dédiée à l'élimination des protéines de lactosérum de l'eau pour laquelle les mécanismes d'élimination sont expliqués et un modèle est développé. Ensuite, l'utilisation de l’EC est étendue à la séparation et à la purification d’acides gras volatils issus de la fermentation acidogénique. Dans cette deuxième étude, les effets des paramètres opératoires sur l'efficacité et le coût de l’EC sont discutés. En outre, l’EC est utilisée pour la récolte de deux espèces de microalgues de leur milieu de culture. En ce qui concerne la récolte de Chlamydomonas reinhardtii, la méthodologie de la surface de réponse est utilisée et deux modèles permettant de prédire respectivement l'efficacité de la récupération et le coût opératoire sont développés. La récolte d’une autre espèce de microalgues, Chlorella vulgaris, est étudiée en utilisant l’EC respectivement en mode discontinu et continu. En mode discontinu, les effets des principaux paramètres de fonctionnement sur l'efficacité du processus sont expliqués et les mécanismes de récupération sont discutés. Dans l'étude en mode continu, la méthodologie de la surface de réponse est utilisée et un modèle permettant de prédire l’efficacité de récupération des microalgues est développé. Enfin, la comparaison des performances de l'EC en mode continu avec et sans échange de polarité aux performances de l'EC en mode discontinu est effectuéeElectrocoagulation (EC) is a non-specific electrochemical method usually used for water and wastewater treatment. In this work, EC is firstly investigated as a conventional wastewater treatment technique for the removal of whey proteins from water, where the mechanisms of removal are explained and a model on whey proteins elimination is developed. Then, EC use is extended for the separation and purification of volatile fatty acids issued from acidogenic fermentation. In this second study, the effects of operating parameters on EC efficiency and cost are discussed. Moreover, EC is used for the harvesting of two microalgae species from their culture medium. In the study that concerns recovering Chlamydomonas reinhardtii, response surface methodology (RSM) is employed and two models for predicting recovery efficiency and operating cost are developed. The harvesting of the other microalgae species Chlorella vulgaris is studied using EC in the batch and continuous modes. In the batch mode, the effects of the main operating parameters on the process effectiveness are explained along with discussing the mechanisms of recovery. In the continuous mode study, response surface methodology (RSM) is applied and a model for predicting microalgae recovery is developed. Finally, comparison of EC performance in continuous mode with and without polarity exchange (PE) to EC performance in batch mode is carried out
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Teixeira, Raimundo Nonato Pereira. "Removal of Cu (II), Ni (II), Cd (II) and Pb (II) of wastewater of electroplating industry using hybrid system adsorption electro-flotation-coagulation." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=13711.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoBodies of water contamination problems have stimulated many researchers around the world in the search for alternatives to solve or minimize the effects caused by discharges of toxic materials to the environment. What is desired, preferably, is that such solutions are economically viable and efficient. Toxic metals on the list of the main contaminants of water bodies. Because these are very dangerous chemicals, this class of materials has led many research groups seeking to achieve avoid contamination of water bodies by this type of material. The wastewater generated by electroplating industries have a high concentration of metal ions, so it should be treated before discharge to receiving waters. The processes using adsorption emerge as one of the research lines most valued by many researchers in order to contribute to this issue. Electrochemical processes have also been tested in the remediation of wastewater contaminated with various pollutants, including toxic metals. Natural clays play an important role in this type of study. Several studies have shown very promising results with the use of such material in the removal of toxic metals. This paper aims to conduct a comparative study of removal efficiency of Cu (II), Ni (II), Cd (II) and Pb (II) from six natural clays Brazilian soil. The clays were used: sodium Clay (AS), green clay (AV), clay chocolate calcium (ACCA), ferric clay (AF), attapulgite (AT) and kaolin (CAU). Balance studies were performed through adsorption isotherms in batch systems. For the balance of studies used monoelementares systems and multielement containing the four metal ions. We have also performed the kinetic study to evaluate the lower equilibrium times. Finally experiments were conducted with hybrid systems which use electrocoagulation-adsorption and coagulation with the purpose of working in a continuous system. The results show that all clays have good adsorption capacity for the four ions. The adsorption equilibrium results were compared with the Langmuir, Freundlich and Temkin. The maximum adsorption capacity obtained from monoelementares solutions were: 50.76 mg.g-1 [AS / Pb (II)], 50.76 mg.g-1 [AV / Cu (II)], 57.14 mg.g-1 [ACCA / Cu (II)], 34.72 mg.g-1 [AF / Cu (II)], 169.4 mg.g-1 [AT / Pb (II)] and 10 29 mg.g-1 [CAU / Cu (II)]. The kinetic model best suited to the experimental data was the pseudo second order. The Webber-Morri diffusion models and Boyd show that adsorption processes occur in more than one step and that in the early days predominates intrafilme diffusion process. The electrocoagulation-clotting experiments associated with adsorption with clays are promising because it promoted an increase in the removal capacity and facilitate the separation of the clay from the aqueous phase. The ion removal capacities of Cu (II) from industrial wastewater using the hybrid system were: 54% [AL / AS] to 45% [Al / ACCA] to 57% [Al / HF] 33% to [AL / AT], 48%
Problemas de contaminaÃÃo dos corpos hÃdricos tÃm estimulado muitos pesquisadores em todo mundo na busca de alternativas que resolvam ou minimizem os efeitos causados pelos descartes de materiais tÃxicos ao meio ambiente. O que se deseja, preferencialmente, à que tais soluÃÃes sejam economicamente viÃveis e eficientes. Os metais tÃxicos fazem parte da lista dos principais contaminantes dos corpos hÃdricos. Por se tratarem de substÃncias quÃmicas bastante perigosas, esta classe de material tem levado muitos grupos de pesquisa na busca de conseguir evitar a contaminaÃÃo dos corpos hÃdricos por este tipo de material. Os efluentes gerados pelas indÃstrias de galvanoplastia possuem uma elevada concentraÃÃo de Ãons metÃlicos, por isso devem ser tratados antes do descarte aos corpos receptores. Os processos que usam adsorÃÃo despontam como uma das linhas de pesquisas mais avaliadas por inÃmeros pesquisadores no intuito de contribuir com esta problemÃtica. Os processos eletroquÃmicos tambÃm tÃm sido testados na remediaÃÃo de efluentes contaminado por diversos poluentes, inclusive metais tÃxicos. As argilas naturais desempenham um papel importante neste tipo de estudo. Diversos trabalhos vÃm apresentando resultados bastante promissores com o uso deste tipo de material na remoÃÃo de metais tÃxicos. Este trabalho se propÃe a realizar um estudo comparativo de eficiÃncia de remoÃÃo dos Ãons Cu(II), Ni(II), Cd(II) e Pb(II) a partir de seis argilas naturais de solo brasileiro. As argilas utilizadas foram: Argila sÃdica (AS), argila verde (AV), argila chocolate cÃlcica (ACCA), argila fÃrrica (AF), atapulgita (AT) e caulim (CAU). Foram realizados estudos de equilÃbrio atravÃs de isotermas de adsorÃÃo em sistemas de batelada. Para os estudos de equilÃbrio utilizaram-se sistemas monoelementares e multielementares contendo os quatro Ãons metÃlicos. Realizou-se tambÃm o estudo cinÃtico para avaliarmos os menores tempos de equilÃbrio. Por fim foram realizados experimentos com sistemas hÃbridos que utilizam adsorÃÃo e eletroflotaÃÃo-coagulaÃÃo, com a finalidade de trabalharmos em sistemas contÃnuos. Os resultados obtidos mostram que todas as argilas apresentam boa capacidade de adsorÃÃo para os quatro Ãons. Os resultados de equilÃbrio de adsorÃÃo foram confrontados com os modelos de Langmuir, Freundlich e Temkin. As capacidades mÃximas de adsorÃÃo obtidas a partir de soluÃÃes monoelementares foram: 50,76 mg.g-1 [AS/Pb(II)], 50,76 mg.g-1 [AV/Cu(II)], 57,14 mg.g-1 [ACCA/ Cu(II)], 34,72 mg.g-1 [AF/ Cu(II)], 169,4 mg.g-1 [AT/Pb(II)] e 10,29 mg.g-1 [CAU/Cu(II)]. O modelo cinÃtico que melhor se adequou aos dados experimentais foi o de pseudo segunda ordem. Os modelos de difusÃo de Webber-Morri e Boyd demonstram que os processos de adsorÃÃo ocorrem em mais de uma etapa e que nos primeiros tempos predomina o processo de difusÃo intrafilme. Os experimentos de eletroflotaÃÃo-coagulaÃÃo associados à adsorÃÃo com argilas mostraram-se promissores porque promoveram um incremento nas capacidades de remoÃÃo e facilitam a separaÃÃo dos argilominerais da fase aquosa. As capacidades de remoÃÃo do Ãon Cu(II) a partir do efluente industrial usando o sistema hÃbrido foram: 54% para [AL/AS], 45% para [AL/ACCA], 57% para [AL/AF] 33% para [AL/AT], 48% para [FE/AS], 47% para [FE/ACCA], 54% para [FE/AF] e 40% para [FE/AT].
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Lian, Ie Tjie. "A eletrocoagulação na terapêutica das lesões intra-epiteliais escamosas de alto grau do colo uterino /." Botucatu : [s.n.], 2001. http://hdl.handle.net/11449/93106.
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Orientador: Paulo TraimanResumo: Analisar a eficácia da eletrocoagulação, como terapêutica nas pacientes portadoras de lesão intra-epitelial escamosa de alto grau de colo uterino. Pacientes e métodos: Estudaram-se prospectivamente 116 pacientes portadoras de lesão intra-epitelial escamosa de alto grau do colo de útero, distribuídas aleatoriamente, com 49 pacientes no grupo de estudo e 67 pacientes no grupo controle. Ambos os grupos foram avaliados quanto à idade, coitarca, paridade, hábito de tabagismo, número de parceiros sexuais, uso de drogas, presença ou antecedente de lesão condilomatosa vulvar, raça e escolaridade. Essas variáveis apresentaram-se homogêneas em ambos os grupos. Todas as pacientes do grupo de estudo e do grupo-controle foram submetidas a colposcopia... (Resumo completo, clicar acesso eletrônico abaixo)
Abstract: Analyzing the efficiency of electrocoagulation as therapeutics in patients carrying high degree squamous intraepithelial lesion of the uterine cervix. Patients and methods: 116 patients carrying high risk intraepithelial lesion of the uterine cervix were prospectively studied, randomly distributed, being 49 patients in the study-group and 67 patients in the control-group. Both groups were evaluated according to age, first copulation, parity, smoking habits, number of sex partners, drug usage, presence or previous condylomatous lesion of the vulva, race and schooling. Such variables were found to be even in both groups. All patients from both groups were submitted to colposcopy, oncological cytology and biopsy of the uterine cervix. The study- group patients were treated with electrocoagulation of the uterine cervix and later submitted to conization after two months. The control-group patients underwent conization only. To assess the significance of the resuts, qui-square and Kappa agreement test were used. Results: In the study-group, electrocoagulation of the uterine cervix caused regression of the lesion in 73,5% of the cases, 20,4% remained unchanged, and there was progression... (Complete abstract click electronic access below)
Mestre
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Butler, Erick. "ELECTROCHEMICAL/ELECTROFLOTATION PROCESS FOR DYE WASTEWATER TREATMENT." Cleveland State University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=csu1375458697.
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Doggaz, Amira. "Déferrisation des eaux par procédé d’électrocoagulation : étude des phénomènes physico-chimiques et réactionnels impliqués." Thesis, Université de Lorraine, 2018. http://www.theses.fr/2018LORR0171.
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La demande croissante en eau nécessite l’exploitation de certaines sources ferrugineuses. Cependant la présence du Fe(II) dissous induit des problèmes d’ordre esthétique et organoleptique. L’électrocoagulation (EC), en tant que procédé substitut de la méthode conventionnelle, a prouvé son efficacité pour l’élimination du fer. En revanche, le mécanisme de déferrisation par EC reste peu connu et non maitrisé. La difficulté de l’étudier provient de l’intervention simultanée de plusieurs phénomènes. Les travaux de cette thèse ont de ce fait pour objectif d’apporter une meilleure compréhension du mécanisme d’élimination du Fe(II) par EC. Ainsi, différentes méthodes d’élimination du fer et des techniques d’analyses du liquide et du solide ont été exploitées. Au moyen d’une unité à recirculation forcée de la solution avec des électrodes en aluminium, la technique d’EC parvient à éliminer 97% d’une solution de 25 mg/L du fer. La quantité optimale d’énergie est de 0,21 kWh/m3. Des essais en milieu anoxique ont montré que la réduction du fer ionique par adsorption sur les flocs de Al(OH)3 est faible (18%). Par oxydation-précipitation à pH 6,5, le Al(OH)3 catalyse la réaction d’oxydation. Cet effet est plus prononcé en présence des ions chlorure qu’en ions sulfate. La spéciation associée à la modélisation cinétique ont permis d’apporter des explications sur le mode d’action de ces ions. Cependant, les expériences par EC en milieux anoxique et oxygéné montrent que la part de l’oxydation dans l’élimination du fer est négligeable pour les pH de travail. Les calculs thermodynamiques au voisinage des électrodes permettent de proposer la précipitation de Fe(OH)2, comme mécanisme prédominant d’élimination du fer par EC. La présence des carbonates réduit la performance du système par la réduction de la précipitation de Fe(OH)2 suite à la diminution du pH local et le Fe2+ libre par formation des complexes du Fe(II)Water scarcity in some areas requires the exploitation of some ferruginous sources. However, the presence of Fe(II) induces aesthetic and organoleptic problems. The electrocoagulation (EC), as an alternative process of the conventional method, proved its efficacy for iron removal. Nevertheless, the iron removal mechanism in EC process remains unstudied and still unclear. The simultaneous involvement of several phenomena makes difficulties to study the system. This thesis aims to provide a better understanding of the mechanism of Fe(II) removal by EC and to highlight the phenomena that are most likely. Thus, different methods of iron removal and liquid and solid analysis techniques have been used. By means of a forced recirculating unit, EC's technique with aluminum electrodes reduce the dissolved iron of 25 mg Fe(II)/L - solution by about 97% with an optimum energy amount of 0,21 kWh/m3. Anoxic experiments showed that the reduction of ionic iron by adsorption on Al(OH)3 flocs is negligible (18%). Oxidation-precipitation experiments showed that at work pH 6,5, Al(OH)3 catalyzes the oxidation reaction. The catalytic effect is more pronounced in the presence of chloride ions than in sulfate ions. Fe(II)-speciation associated with kinetic modeling have allowed to explain of the mode by which these ions acts on the oxidation reaction kinetics. However, EC experiments in anoxic and oxygenated media show that the proportion of oxidation in iron removal is insignificant for work pH. Thermodynamic calculations allowed to propose the precipitation of Fe(OH)2 in the vicinity of the cathode as the predominant mechanism of iron removal by EC. The presence of carbonates affects the performance of the process by reducing the precipitation of Fe(OH)2; this was attributed to the decrease of the local pH and the free Fe(II) amount by Fe(II)-complexes formation