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In this study, the optimum operating conditions for the treatment of emulsified oils by electrocoagulation were determined depending on droplet stability analysis. Zeta potential measurements were used as the indication of oil droplet charges. In addition, the effects of pH and ionic conductivity on the droplet sizes and surface charges were investigated. The studied emulsified oil droplet sizes were more sensitive to changes in pH rather than salt concentration. The droplets became larger and unstable in alkaline conditions. As the initial pH of wastewaters increased, the oil removal efficiency increased during the electrocoagulation experiments as well. The use of iron or aluminum electrodes resulted in higher removal efficiencies in comparison to stainless steel electrodes. In addition, the energy consumption for aluminum electrodes was much lower than iron electrodes. To obtain 98% oil removal efficiency, distance between the electrodes was recommended to be less than or equal to 1 cm. [ABSTRACT FROM AUTHOR]

The removal mechanism of batch electrocoagulation (EC) process for removing Cr ions was investigated. The influence of operation parameters on removal mechanisms was discussed. The utilization rate of in situ electro-generated Fe ions in the sludge was introduced to investigate the removal mechanism and optimize the EC process. The Fe elements' utilization rate resulting from the specific adsorption is much higher than that resulting from precipitation and co-precipitation. The initial pH determines which removal mechanism dominates the Cr removal. At neutral initial pH condition, Cr ions are mainly removed by flocs' surface complexation reaction (specific adsorption). The utilization rate of Fe ions at neutral pH condition reaches its maximum and is higher than that at other pH conditions. The influence of electrode material on EC performance was investigated on the basis of utilization rate of Fe ions. For EC with Fe/Al electrode combination, although direct dissolution of Al ion from Al electrodes will improve the Cr(VI) removal efficiency, the utilization rate of generated metal ions is much lower, when compared with EC with Fe/Fe electrode. The utilization rate of in situ electro-generated metal ions could be considered as a new index to evaluate EC performances. [ABSTRACT FROM AUTHOR]

A hybrid electrocoagulation process using iron electrode was developed for removal of organic pollutants from distillery industrial effluent. Combinations of electrocoagulation process with different advanced oxidation processes such as electrocoagulation, photo-electrocoagulation, peroxi-electrocoagulation and peroxi-photo-electrocoagulation processes investigated and compared in terms of color removal, Chemical Oxygen Demand (COD) removal and electrical energy consumption. An overall COD removal efficiency of 85% with 1.20 kWh/m³ of energy consumption, current density of 0.13 A/dm², initial COD concentration of 2500 ppm, initial pH of 7, H2O2 concentration of 234 mg/L, stirring speed of 100 rpm and reaction time of 240 min was observed in the peroxi-electrocoagulation process. The effects of different operating parameters such as initial pH of the effluent (3-11), current density (0.03-0.23 A/dm²) and concentration of H2O2 (58.5-585 mg/L) on color removal, COD removal and electrical energy consumption were studied. The direct- and alternating-current electrocoagulation processes were also studied. [ABSTRACT FROM AUTHOR]

In this study, the purification of the waste water obtained from the cotton textile industry was performed by the electrocoagulation (EC) method. To increase the efficiency of the treatment, the simultaneous control of temperature, conductivity and pH is performed using fuzzy control method. Before being passed to the control operation, Design Expert program with the effects on the textile industry waste water electrocoagulation performing optimization experiments were investigated and discussed whether it is necessary to control experiments. Following these studies have been conducted control experiments. In control experiments, MATLAB/Simulink has been used. The removal efficiencies of chemical oxygen demand (COD), color, turbidity and oil and grease (O&G) were found as 76.2%, 88.9%, 91.6% and 74.2%, respectively. Consequently, the EC is in the process of waste water treatment in the textile industry is an effective method and fuzzy control method with simultaneous control of temperature-conductivity-pH has been shown to increase the effectiveness of the method also being used. [ABSTRACT FROM AUTHOR]

Introduction. This research was carried out to study of electrocoagulation process as a new technique for removal of impurities and non-sucrose compounds from raw sugar beet juice. Materials and methods. This study was performed in a batch chemical reactor equipped with a 5-liters tank containing 3 aluminium anode and 3 Iron cathode electrodes connected in parallel. Effects of voltage at 5, 10 and 15 volts; processing time at 15, 30 and 45 minute intervals; and pH value at 6, 7 & 8 levels on the purity, turbidity and colour of the sugar beet juice were investigated by the Box-Behnken response surface methodology statistical design on Minitab 17 statistical software. Results and Discussion. The results indicated that during the EC process, turbidity was reduced as the voltage increased. As the voltage rises, the solubility of the anodal electrodes also increases resulting in removal of a larger quantity of pollutants. Therefore, reduction in turbidity following the rise in voltage can be attributed to the increase in flake production, while changes in pH value had no significant effect on turbidity. Although the increase in voltage did not significantly effect the intensification of the colour, however it can be attributed to the increase in bubbles and the subsequent increase in enzymatic activity during floatation. It seems that the increase in enzymatic activity intensifies the melanin colour with the passage of time due to the openness of the reactor cell during flotation and aeration. Increase in the pH value, however, only slightly intensified the colour. The results indicated that the increase in voltage resulted in increase in the level of purity. The solubility of the anodal electrodes increases as the voltage rises and subsequently a higher quantity of impurities and polutants are removed by aluminium hydroxides produced. Increase in voltage also leads to production of greater quantity of bubbles which increase contact between aluminium hydroxides with the pollutants and impurities and facilitates the floatation of more of the produced sludge and thus removal of a greater quantity of the impurities. Increase in process time also resulted in an increase in the level of purity as an increase in reaction time results in more floating sludge is produced on the fluid surface. Increase in the pH value had no significant effect on the level of purity. Conclusion. The results generally indicated that electrocoagulation process has positively affected on the turbidity reduction and increase the purity of the raw sugar beet juice during the process of purification though colour intensity was not so significantly influenced. [ABSTRACT FROM AUTHOR]

In this research paper, a combination of biofiltration (BF) and electrocoagulation (EC) processes was used for the treatment of sanitary landfill leachate. Landfill leachate is often characterized by the presence of refractory organic compounds (BOD/COD < 0.13). BF process was used as secondary treatment to remove effectively ammonia nitrogen (N-NH 4 removal of 94%), BOD (94% removed), turbidity (95% removed) and phosphorus (more than 98% removed). Subsequently, EC process using magnesium-based anode was used as tertiary treatment. The best performances of COD and color removal from landfill leachate were obtained by applying a current density of 10 mA/cm 2 through 30 min of treatment. The COD removal reached 53%, whereas 85% of color removal was recorded. It has been proved that the alkalinity had a negative effect on COD removal during EC treatment. COD removal efficiencies of 52%, 41% and 27% were recorded in the presence of 1.0, 2.0 and 3.0 g/L of sodium bicarbonate (NaHCO 3 ), respectively. Hydroxide ions produced at the cathode electrode reacted with the bicarbonate ions to form carbonates. The presence of bicarbonates in solution hampered the increase in pH, so that the precipitation of magnesium hydroxides could not take place to effectively remove organic pollutants. [ABSTRACT FROM AUTHOR]

Despite their high boron contents, some boron deposits contain considerable amounts of arsenic. Its toxicology and health hazard also has been reported for many years. In this work arsenic and boron removal from synthetic water was studied on laboratory scale by electrocoagulation using aluminum electrodes. The influence of main operating parameters such as current density, stirring speed, supporting electrolyte type and concentration on the arsenic and boron removal was investigated. Waste water sample was prepared with initial arsenic concentration of 50 mg L-1 and boron concentration of 1000 mg L-1. Current density was varied from 0.18 to 4.28 mA cm-2, stirring speed was varied as 50, 150, 250, 350 rpm, NaCl, KCl and Na2SO4 were used as supporting electrolyte. The obtained experimental results showed that efficiency of arsenic and boron removal increased with increasing current density. As the current density increases, the potential difference applied to the system also increases the energy consumption. Increasing the supporting electrolyte concentration increased conductivity of solution and decreased energy consumption. The most favorable supporting electrolyte type was NaCl for arsenic and boron removal. The best stirring speed were 150 rpm for arsenic and boron removal. [ABSTRACT FROM AUTHOR]

This paper evaluated a novel pilot scale electrocoagulation (EC) system for improving total phosphorus (TP) removal from municipal wastewater. This EC system was operated in continuous and batch operating mode under differing conditions (e.g. flow rate, initial concentration, electrolysis time, conductivity, voltage) to evaluate correlative phosphorus and electrical energy consumption. The results demonstrated that the EC system could effectively remove phosphorus to meet current stringent discharge standards of less than 0.2 mg/L within 2 to 5 min. This target was achieved in all ranges of initial TP concentrations studied. It was also found that an increase in conductivity of solution, voltages, or electrolysis time, correlated with improved TP removal efficiency and reduced specific energy consumption. Based on these results, some key economic considerations, such as operating costs, cost-effectiveness, product manufacturing feasibility, facility design and retrofitting, and program implementation are also discussed. This EC process can conclusively be highly efficient in a relatively simple, easily managed, and cost-effective for wastewater treatment system. [ABSTRACT FROM AUTHOR]

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box-Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5-15 V), initial pH (4.5-8.0) and time (30-90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P>0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R2 and Radj 2 values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R2 values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage-time and pH-time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect. [ABSTRACT FROM AUTHOR]

The present work investigates the feasibility of re-using partially purified iron fixation solutions by electro-coagulation followed by ozonation in another fixation stage of black ripe olive processing and/or as cover brines in packaging. Re-use after the addition of ferrous gluconate during the color fixation stage involves a slightly lower amount of iron penetrating into the olives than when tap water is used. As a result, the olives are slightly less dark before packing when a gluconate solution is re-used. However, it is possible to completely re-use the partially purified solution using 50% of it as a color fixing liquid and 50% to prepare the cover brine in the packaging or to fix the color using tap water to prepare the gluconate solution and 100% purified solution as cover brine, in which case this waste-water is completely eliminated from the industry. Iron concentration in the flesh and surface color are the same for these two working methods and ripe olives present the same flavor as olives produced following the traditional procedure using only tap water. [ABSTRACT FROM AUTHOR]

In this study, the efficiency of ozonation, electrocoagulation and ozone assisted electrocoagulation processes for removal of pollutants from effluent of distillery industry was compared. The experimental results showed that ozone assisted electrocoagulation process yielded higher pollutant removal than ozone and electrocoagulation processes alone. Response surface methodology based on central composite design was used to optimize various operating parameters of the ozone assisted electrocoagulation process for the treatment of industrial effluent. The effects of five independent parameters such as current density(X 1 ), COD concentration(X 2 ), effluent pH(X 3 ), inter-electrode distance(X 4 ) and electrolysis time(X 5 ) on the% COD removal and power consumption were investigated. A quadratic model was used to predict the COD removal and power consumption in different conditions. The significance of independent variables and their interaction were evaluated by ANOVA. In order to achieve the maximum COD removal and minimum power consumption, the optimum conditions were obtained by mathematical and statistical methods. The results showed that maximum COD removal efficiency could be achieved at optimum conditions of X 1 − 3A/dm 2 , X 2 − 3000 ppm, X 3 − 7, X 4 − 1.8 cm and X 5 − 5 h. In conclusion, hybrid electrocoagulation process could be applied successfully for removing pollutants from effluent. [ABSTRACT FROM AUTHOR]

Batch experiments were conducted to investigate the effects of cathode materials and anions (Cl − , SO 4 2 − , NO 3 − , and CO 3 2 − /HCO 3 − ) on perfluorooctanoate (PFOA) removal in electrocoagulation process using zinc anode. The results indicated that the hydroxide flocs generated in-situ in the electrocoagulation process using the stainless steel rod as cathode were more effective than those using aluminum rod as cathode for the removal of PFOA after 20 min of electrocoagulation at a current density of 0.5 mA cm − 2 . Hydroxide flocs generated in-situ in the electrocoagulation in the presence of Cl − /NO 3 − could effectively remove PFOA from aqueous solution with the removal ratios of 99.7%/98.1% and 98.9%/97.3% using stainless steel rod and aluminum rod as cathode, respectively. However, the PFOA removal ratios were 96.2%/4.1% and 7.4%/4.6% using stainless steel rod and aluminum rod as cathode, respectively, in the presence of SO 4 2 − and CO 3 2 − /HCO 3 − . The different removal ratios of PFOA during the electrocoagulation process were primarily due to the fact that the hydroxide flocs generated in-situ were different in the presence of diverse cathodes and anions. We firstly demonstrated that Zn 0.70 Al 0.30 (OH) 2 (CO 3 ) 0.15 · x H 2 O and ZnO generated in-situ in the electrocoagulation process (except for CO 3 2 − /HCO 3 − ) using zinc anode and aluminum/stainless steel rod cathode governed the sorption of PFOA. The adsorbent hydroxide flocs in-situ generated in the presence of Cl − could effectively remove PFOA from aqueous solution containing CO 3 2 − /HCO 3 − anion at the initial hydroxide flocs concentration of 2000 mg L − 1 . These results provided an effective and alternative method to remove PFOA from aqueous solution containing CO 3 2 − /HCO 3 − anion. [ABSTRACT FROM AUTHOR]

The potential of continuous electrocoagulation (EC) process with aluminium electrodes for the post-treatment of upflow anaerobic sludge blanket (UASB) reactor-treated municipal wastewater was investigated. In order to optimise the performance, influence of three parameters affecting EC, namely, chemical oxygen demand (COD), current density (CD) and residence time in the reactor was studied using response surface methodology (RSM) with Box-Behnken design (BBD) employing real UASB reactor effluent. The results of the modelling study gave the following optimum conditions: influent COD concentration 274mg/L, CD 2 mA/cm2 and residence time 5 min; and predicted effluent COD, phosphate and turbidity values of 87 mg/L, 0.59 mg/L, and 12.6NTU, respectively. Confirmatory tests at these optimum conditions gave 90 mg/L effluent COD, 0.57 mg/L effluent phosphate and 15.2 NTU effluent turbidity, which were in close agreement with the predicted results. At optimum conditions, high removals of BOD and suspended solids were also observed, with effluent BOD and suspended solids concentration of 34 mg/L and 29 mg/L, respectively. High total coliform and faecal coliform removals of 99.81% and 99.86%, respectively, were also obtained at these conditions. The study thus suggests EC as an attractive post-treatment option for UASB reactor-treated municipal wastewater. [ABSTRACT FROM AUTHOR]

This paper investigates the optimum operational conditions of a novel rotated bed electrocoagulation (EC) reactor for the treatment of textile wastewater. The effect of various operational parameters such as rotational speed, current density (CD), operational time (RT), pH, temperature, and inter-electrode distance (IED) on the pollutant removal efficiency were examined. In addition, the consumption of aluminum (Al) and electrical energy, as well as operating costs at optimum conditions were also calculated. The results indicated that the optimum conditions for the treatment of textile wastewater were achieved at CD = 4 mA/cm 2 , RT = 10 min, rotational speed = 150 rpm, pH = 4.57, temperature = 25 °C, and IED = 1 cm. The electrode consumption, energy consumption, and operating costs were 0.038 kg/m 3 , 4.66 kWh/m 3 and 0.44 US$/m 3 , respectively. The removal efficiencies of chemical oxygen demand (COD), biological oxygen demand (BOD), total suspended solid (TSS), turbidity and color were 97.10%, 95.55%, 98%, 96% and 98.50%, respectively, at the first 10 min of reaction time, while the phenol compound of the wastewater was almost entirely removed (99.99%). The experimental results confirm that the new reactor design with rotated anode impellers and cathode rings provided high treatment efficiency at a reduced reaction time and with lower energy consumption. [ABSTRACT FROM AUTHOR]

Extended field trials to remove arsenic (As) via Fe(0) electrocoagulation (EC) have demonstrated consistent As removal from groundwater to concentrations below 10 μg L −1 . However, the coulombic performance of long-term EC field operation is lower than that of laboratory-based systems. Although EC electrodes used over prolonged periods show distinct passivation layers, which have been linked to decreased treatment efficiency, the spatial distribution and mineralogy of such surface layers have not been investigated. In this work, we combine wet chemical measurements with sub-micron-scale chemical maps and selected area electron diffraction (SAED) to determine the chemical composition and mineral phase of surface layers formed during long-term Fe(0) EC treatment. We analyzed Fe(0) EC electrodes used for 3.5 months of daily treatment of As-contaminated groundwater in rural West Bengal, India. We found that the several mm thick layer that formed on cathodes and anodes consisted of primarily magnetite, with minor fractions of goethite. Spatially-resolved SAED patterns also revealed small quantities of CaCO 3 , Mn oxides, and SiO 2 , the source of which was the groundwater electrolyte. We propose that the formation of the surface layer contributes to decreased treatment performance by preventing the migration of EC-generated Fe(II) to the bulk electrolyte, where As removal occurs. The trapped Fe(II) subsequently increases the surface layer size at the expense of treatment efficiency. Based on these findings, we discuss several simple and affordable methods to prevent the efficiency loss due to the surface layer, including alternating polarity cycles and cleaning the Fe(0) surface mechanically or via electrolyte scouring. [ABSTRACT FROM AUTHOR]

In this study, ultrasonic treatment was used to remove the passive film that formed on electrode surface during electrocoagulation (EC). The variation of electrode impendence was examined to evaluate the effect of passivation on EC and the ultrasound-electrocoagulation (sono-EC) process. The effects of operating parameters current density, pH and ultrasonic power on the removing efficiency in sono-EC were studied. A synthetic wastewater that contained Reactive Blue 19 dye was used in all experiments. The results demonstrated that the electrode impedance increased during the EC process but decreased during the sono-EC process, indicating that the passive film can be removed from the sacrificial electrode using ultrasound, causing the sacrificial electrode to generate more coagulant metal. Additionally, the ultrasound reduces the size of the metal hydroxide which in turn adsorb more contamination in synthetic wastewater. The SEM results show that ultrasound process could successfully remove the passive film on the plates. An intermittent ultrasonic process and double-type reactor were utilized to reduce the breaking of flocs in the system. A total of 97% of the RB19 was removed by intermittent sono-EC treatment at a current density of 18 mA/cm 2 , a pH of 5, an electrolysis time of 60 min and an ultrasound power of 150 W. Furthermore, the remove of the RB19 in the sono-EC process can be well expressed by a variable-order-kinetic model in the sono-EC system. In conclusion, ultrasonic equipment improves EC performance by removing the passive film. [ABSTRACT FROM AUTHOR]

Electro-coagulation (EC) is an alternative method to standard chemical coagulation, which is one of the most common water and wastewater treatment processes, employed to remove a wide range of contaminants through (co)precipitation processes. Despite the attention EC has received over the last decade, misconception regarding key process parameters exists and a lack of standardised procedure impacts on the progress of this promising field. It is demonstrated here how, unlike frequently reported in the literature, a fundamental process parameter – current intensity – is the process determining step with regards to extent of contaminant removal (rather than current density). Furthermore, terminology is proposed with a view to unify communication and to facilitate performance interpretation and comparison of datasets whilst the jar-testing procedure is presented as standardized method for process evaluation with the same objective in mind. Finally, shortfalls and solutions to experimental design are discussed and presented. [ABSTRACT FROM AUTHOR]

As the ponding system used to treat palm oil mill effluent (POME) frequently fails to satisfy the discharge standard in Malaysia, the present study aimed to resolve this problem using an optimized electrocoagulation process. Thus, a central composite design (CCD) module in response surface methodology was employed to optimize the interactions of process variables, namely current density, contact time and initial pH targeted on maximum removal of chemical oxygen demand (COD), colour and turbidity with satisfactory pH of discharge POME. The batch study was initially designed by CCD and statistical models of responses were subsequently derived to indicate the significant terms of interactive process variables. All models were verified by analysis of variance showing model significances with Prob >F< 0.01. The optimum performance was obtained at the current density of 56 mA/cm2, contact time of 65 min and initial pH of 4.5, rendering complete removal of colour and turbidity with COD removal of 75.4%. The pH of post-treated POME of 7.6 was achieved, which is suitable for direct discharge. These predicted outputs were subsequently confirmed by insignificant standard deviation readings between predicted and actual values. This optimum condition also permitted the simultaneous removal of NH3-N, and various metal ions, signifying the superiority of the electrocoagulation process optimized by CCD. [ABSTRACT FROM AUTHOR]

Some boron deposits in Turkey contain considerable amounts of arsenic. Arsenic in the boron deposits can create a great risk due to its environmental effects on surface and underground waters. Water sources containing more than a certain concentration of boron and arsenic have negative effects on plants, animals and human beings. Thus, their removals are necessary. In this paper, the removal of arsenic (As) and boron (B) from aqueous solutions by electrocoagulation using aluminum (Al) electrode material was investigated. Specifically, the effects of initial pH, initial arsenic and boron concentrations and operating time on the performance of EC were investigated. Experiments were carried out with different pHs ranging from 2 to 8. Results showed that initial pH was highly effective on the efficiency and high removal efficiencies were observed at initial pH of 4.0 for both arsenic and boron. Initial arsenic and boron concentration affected the removal efficiencies. Arsenic removal efficiency decreased with increasing boron concentration, and boron removal efficiency decreased with increasing arsenic concentration. The results also showed that boron ions prevented to arsenic removal and boron ions competed with arsenic ions. This situation led to the low arsenic and boron removal. [ABSTRACT FROM AUTHOR]

Electrocoagulation (EC) can be used to remove nutrients as well as suspended solids and organic carbon from wastewaters, but the high energy requirements (pumping air) and the use of precious metals in some processes has hindered widespread application of EC technologies. The use of a thermodynamically favorable activated carbon air cathode and a sacrificial aluminum anode was examined to reduce the energy needed for EC for nutrient removal. Performance of the air cathode electrocoagulation (ACEC) process was tested using raw wastewater, and a carbon-free synthetic solution (nitrogen:phosphorus ratio of 1:10 in deionized water) to simulate nutrient removal of a wastewater treated for organic matter removal. ACEC treatment of wastewater removed up to 99% of both ammonia and phosphorus, along with 72–81% COD and 78–89% TSS in 4 h (1.5 cm electrode spacing, current density of 8 A m −2 ). Nearly total removal of the nutrients required 1.8 kWh m −3 , which is lower than that previously reported for some EC processes for this application (0.4–22 kWh m −3 ). Nutrient removals using synthetic solutions (no organic matter) ranged from 74% to 93% for nitrogen (47–370 mg-N/L) and 44–76% for phosphorus. These results indicate that the ACEC can achieve good levels of nutrient removal with reduced energy demands compared to previous EC systems. [ABSTRACT FROM AUTHOR]

In this work, optimization of total organic carbon (TOC) removal for the treatment of lithographic wastewater by electrocoagulation followed by photocatalytic process was developed. It was used a response surface methodology (RSM) for the optimization of the process variables, such as current density for electrocoagulation process, TiO 2 concentration for photocatalytic process, and pH in both cases. Optimal conditions for the process were obtained with TOC removal above 65% using electrochemical process by 30 min of operation. A total of 25% of residual TOC was removed employing the photocatalytic process, for a total of 74% of removal of TOC from the initial value. A kinetic modeling was performed for both processes to pseudo-second-order equations. The treated water is colorless and could be suitable for cleaning water in the lithographic process. [ABSTRACT FROM AUTHOR]

The present study investigates the electrocoagulation-electroreduction (EC-ER) and ozonation process (ECRO process) for the treatment of grey wastewater (GWW) loaded with organic and inorganic matter, oil and greases (O&G), and total suspensions solids (TSS). Several factors, such as electrode materials, current density, electrolysis time, initial pH, wastewater conductivity, and ozone dosage were investigated. High treatment efficiency of GWW was recorded while applying the EC-ER technique followed by the ozonation process. The best performance forGWWtreatment by the EC-ER process was obtained using aluminum and graphite electrodes operated at current density of 0.9 A=dm2, during 90 min of electrolysis time and at pH around 10 whereas the ozonation treatment of GWW was found to be more effective at pH 8 and at 9.2 g=h of ozone dosage. Under these optimal conditions, combining the electrochemical (EC-ER) and ozonation processes enhanced the removal of organic and inorganic contaminants from GWW. The ECRO process reduced total chemical oxygen demand (CODT) by 91.31±1.09%, total organic carbon (TOC) by 84.59±1.71%, soluble chemical oxygen demand (CODs) by 90.17±0.26%, and dissolved organic carbon (DOC) by 82.11±2.19%. Besides, the removal efficiency of biological organic demand (BOD), O&G, and total phosphorous (PT) reached 92.61±0.24%, 90.40±0.31%, and 86.66±0.00%, respectively. [ABSTRACT FROM AUTHOR]

In this study, response surface methodology (RSM) was used to investigate the effects of different operating conditions on the removal of ciprofloxacin (CIP) by the electrocoagulation (EC) with pure iron electrodes. Box-Behnken design was used for the optimization of the EC process and to evaluate the effects and interactions of process variables such as applied current density, process time, initial CIP concentration and pH on the removal of CIP by the EC process. The optimum conditions for maximum CIP removal (86.6%) were found as pH= 4; Co = 5 mg.L1-; Id = 4.325 mA.cm2-; tprocess= 10 min. The model adequacy and the validity of the optimization step were confirmed with additional experiments which were performed under the proposed optimum conditions. The predicted CIP removal as 86.6% was achieved at each experiment by using the optimum conditions. These results specify that the RSM is a useful tool for optimizing the operational conditions for CIP removal by the EC process [ABSTRACT FROM AUTHOR]

Electrocoagulation (EC) is the intentional corrosion of sacrificial anodes (typically aluminum or iron) by passing electricity to release metal-ion coagulant species and destabilize a wide range of suspended, dissolved, and macromolecular contaminants. It can be integrated ahead of microfiltration (MF) to effectively control turbidity, microorganisms, and disinfection by-products (DBPs) and simultaneously maintain a high MF specific flux. This manuscript summarizes the current knowledge on MF pretreatment by aluminum EC particularly focusing on mechanisms of (i) electrocoagulant dosing, (ii) (bio)colloid destabilization, (iii) fouling reductions, and (iv) enhanced removal of viruses, natural organic matter (NOM), and DBP precursors. Electrolysis efficiently removes hydrophobic NOM, viruses, and siliceous foulants. Aluminum effectively electrocoagulates viruses by physically encapsulating them in flocs, neutralizing their surface charge and reducing electrostatic repulsion, and increasing hydrophobic interactions between any sorbed NOM and free viruses. New results included herein demonstrate that EC achieves DBP control by removing NOM, reducing chlorine-reactivity of remaining NOM, and inducing a slight shift toward more brominated trihalomethanes and haloacetic acids. EC reduces MF fouling by forming large flocs that tend to deposit on the membrane surface, i.e. decrease pore penetration and forming more permeable cakes and by reducing foulant mass in case of significant floc-flotation. [ABSTRACT FROM AUTHOR]

Treatment of a real dyehouse wastewater was studied with continuous flow electrocoagulation (CEC) process. Removal efficiencies of COD, TOC and turbidity were obtained as 85%, 76% and 95% for Fe electrode and 77%, 72% and 95% for Al electrode at current density of 65 A/m 2 , inlet flow rate of 0.010 L/min, operating time of 80 min (hydraulic retention time of 350 min), and current density of 65 A/m 2 (the optimum operating conditions). The decrease in the inlet flow rate (0.20–0.010 L/min) led to an increase in removal efficiencies of COD (58–85% for Fe, 55–77% for Al), TOC (51–76% for Fe and 46–72% for Al) and turbidity (70–95% for Fe and 72–95% for Al). Operating costs for Fe and Al electrodes at the optimum operating conditions were calculated as 1.562 $/m 3 or 7.282 $/kg COD for Fe electrode and 1.851 $/m 3 or 14.257 $/kg COD for Al electrode. The results presented in this study revealed that the CEC process can be effectively used for the removals of color, COD, TOC and turbidity from textile wastewater. [ABSTRACT FROM AUTHOR]

A pilot-scale study was conducted using electrocoagulation technology to treat chlorine dioxide bleaching-stage effluent of a local pulp mill, with the purpose of evaluating the treatment performance. The operating variables were the current density (0 ~ 133.3 Am2) and hydraulic retention time (HRT, 6.5 ~ 16.25 minutes). Water quality indicators investigated were the conductivity, suspended solids (SS), chemical oxygen demand (COD), true color, and hardness. The results showed that electrocoagulation technology can be used to treat D-stage bleaching effluent for water reuse. Under the operating conditions studied, the removal of conductivity and COD always increased with increases in either the current density or HRT. The highest removals obtained at 133.3 A/m2 and an HRT of 16.25 minutes for conductivity, SS, COD, true color, and hardness were respectively 44.2, 98.5, 75.0, 85.9, and 36.9% with aluminum electrodes. Iron electrodes were not applicable to the D-stage effluent due to formation of dark-colored ferric complexes. [ABSTRACT FROM AUTHOR]

A point-of-use prototype electrocoagulation treatment system was designed and evaluated for its ability to remove arsenic from a synthetic groundwater. The system was comprised of an electrocoagulation reactor providing batch treatment, a rechargeable battery power source, an electrical monitoring and control module, and a granular media filter. The control module and the filter underdrain system were designed to improve user convenience. The system was able to consistently reduce arsenic concentrations to below 20 μg/L. Effluent soluble arsenic concentrations under 10 μg/L were deemed possible with enhanced effluent suspended solids removal techniques. Arsenic removal was found to be a function of the initial arsenic concentration and the cumulative charge dosage as measured in coulombs per liter of water treated. The steel plate size used in the electrocoagulation module influenced the current draw and the overall electrical efficiency of the system. The monitoring and control module allowed the system to produce up to 100 liters of treated water daily on a single battery charge and would automatically control charge and iron dosage. The point-of-use system was capable of meeting household potable demands for water where other treatment options are limited. [ABSTRACT FROM AUTHOR]

A batch electrocoagulation study was conducted using aluminium electrodes to check the treatability of synthetic bilge water. The studies were conducted to investigate the effect of various operational parameters on the treatment efficiency. At a pH of 7, applied voltage of 10 V, spacing of 1 cm and effective electrode area of 45 cm 2 , a maximum soluble COD (COD S ) removal efficiency of 85% was obtained after an electrolysis time of 120 min. The second order rate constant was derived and a maximum rate constant of 3 × 10 −6 L/mg-min was observed at optimum experimental conditions. COD S experimental measurements give an acceptable fit for both Langmuir model and Freundlich isotherm models. A comparative study between electrocoagulation and chemical coagulation was performed and chemical coagulation showed only 59.3% removal efficiency. The sludge formed after the electrocoagulation process was characterized for mineral composition and functional groups. XRD and FTIR results represent the formation of aluminium hydroxide during electro coagulation process and the presence of hydrocarbons and heavy metals in the sludge indicates the removal of these pollutants from bilge water by electrocoagulation process. Among different electrode combinations of aluminium and iron, Al Al combination showed maximum removal efficiency. A case study on real bilge water was conducted and a maximum removal of 89.84% was obtained at optimum conditions using aluminium electrodes. [ABSTRACT FROM AUTHOR]

The treatment of distillery industrial effluent by means various combinations of electrocoagulation with Advanced Oxidation Processes (AOPs) such as ozonation, electrocoagulation, peroxi-electrocoagulation, photo-electrocoagulation, ozone-electrocoagulation and peroxi-photo-electrocoagulation process on the removal of percentage color, COD and energy consumption. The effects of various operating parameters such as ozone flow rate (5 to 15 LPM), initial effluent pH (2 to 10), current density (0.10 to 0.50 A/dm2) and H2O2 concentration (50 to 500 mg/L) on the removal of pollutant were studied in this study. Moreover comparison of all the processes in terms of color removal, COD removal and energy consumption was also carried out. The experimental results showed that100% of color and COD removal could be achieved by ozone-electrocoagulation process with an energy consumption of 5.7 kW h/m3 within four hours of reaction time. The extent of color and COD removal was analyzed using a UV/vis spectrophotometer and closed reflux method. [ABSTRACT FROM AUTHOR]

An integrated system of electrocoagulation and algal cultivation was developed to treat a high strength wastewater—anaerobic digestion liquid effluent for reclaimed water and value-added algal biomass production. The integrated system synergistically takes advantages of both electrocoagulation and algal cultivation to enhance the efficiencies of wastewater treatment. The electrocoagulation treated wastewater had low turbidity with better light penetration (108 NTU) to enable algal growth. The algal cultivation had high removal efficiencies of phosphorus (99.4%) and nitrogen (88.2%). The dissolved iron in the electrocoagulation treated wastewater enhanced lipid accumulation of the algae. The results present that total phosphorus and nitrogen in the reclaimed water were 0.78 g L −1 and 35.5 mg L −1 respectively, and the harvested algal biomass had 35% of lipid, 53% of protein, and 6.4% of carbohydrate. This study concluded a new route for agricultural wastewater treatment that turns wastewater from an environmental liability into a valuable asset. [ABSTRACT FROM AUTHOR]

Nanofiltration (NF) is a promising technique since it can reclaim the concentrated nutrients from the biogas digestion slurry from swine farms, and produce reusable permeates. However, a lack of efficient and reasonable pretreatment processes to alleviate membrane fouling has become one of the main obstacles for practical NF applications. In this study, an electrocoagulation (EC) process was developed to pretreat biogas digestion slurry prior to NF. It was found that current density had the most significant effect on turbidity removal and electric energy consumption of the EC process, and the optimal combination for a high turbidity removal (65.6%) with low electric energy (0.73 W h L −1 ) consumption was determined by the response surface method as current density of 35.7 A m −2 , reaction time of 24 min, and A / V of 20.7 m 2 m −3 . Finally, the EC was proved to be able to alleviate NF membrane fouling by 22.2% for treating biogas digestion slurry. [ABSTRACT FROM AUTHOR]

Chloride (Cl − ) is widely used for depassivation in electrocoagulation using metallic iron (Fe 0 -EC). However, its optimization is still on a pragmatic approach and thus of limited success. This study proposed a novel approach based on a systematic investigation of Cl − –induced pitting dissolution behavior of Fe 0 with the evolution of pH and Cr(VI) (0 ⩽ Cr(VI) (mg/L) ⩽ 520) in Fe 0 -EC. The depassivation behavior was characterized by potentiodynamic polarization, cyclic voltammograms (CVs), galvanostatic measurements, and scanning electron microscope (SEM) analysis. The proposed approach to optimize Cl − for depassivation was as follows: (1) Build a database of minimum Cl − concentrations for pitting dissolution (MCPD) as a function of pH and Cr(VI) in passivation region III (MCD = f (pH, Cr(VI))); (2) Record the curve function ( g ) of pH and Cr(VI) evolution ( g = {(pH i , Cr(VI) i ), …, (pH f , Cr(VI) f )}) without passivation in the Fe 0 -EC process; (3) Obtain the optimal concentration of Cl − for depassivation (OCD) by selecting the maximum MCDs by combining the curve ( g ) and the database of MCPD (OCD = Max {MCPD 1 , MCPD 2 , … MCPD n }). This method was more accurate and stable compared with RSM. [ABSTRACT FROM AUTHOR]

The efficiency of iron electrode based electrocoagulation (EC) technique at laboratory scale to remove lead (Pb) from battery industrial effluent in Bangladesh is investigated. Different combinations of voltage (15, 30 and 45), effluent pH (1, 3, 5, 7 and 9) and electrolysis time (15, 30, 45 and 60 minutes) at the EC reactor was examined for searching the ideal operating conditions of maximum lead removal. Initial battery effluent pH of 3, electro coagulating at 30 V for 15 minutes would be the optimum conditions for treatment where 99.9% Pb removal was achieved. Treated effluent quality was compared with national environmental standard to discharge into surface water bodies and found physico-chemical parameters (TDS, TSS, DO and pH) were within prescribed limit except electrical conductivity. [ABSTRACT FROM AUTHOR]

The removal efficiencies of electrocoagulation (EC) systems are highly dependent on the initial value of pH. If an EC system has an acidic influent, the pH of the effluent increases during the treatment process; conversely, if such a system has an alkaline influent, the pH of the effluent decreases during the treatment process. Thus, changes in the pH of the wastewater affect the efficiency of the EC process. In this study, we investigated the dynamic effects of pH. To evaluate approaches for preventing increases in the pH of the system, the MATLAB/Simulink program was used to develop and evaluate an online computer-based system for pH control. The aim of this work was to study Proportional-Integral-Derivative (PID) control and fuzzy control of the pH of a real textile wastewater purification process using EC. The performances and dynamic behaviors of these two control systems were evaluated based on determinations of COD, colour, and turbidity removal efficiencies. [ABSTRACT FROM AUTHOR]

Although much research effort has focused on methods to mitigate fouling of membrane bioreactors (MBRs), fouling is still inevitable. This paper aims to corroborate the roles of electro-coagulation approach within a coagulation-assisted MBR, termed electro-MBR. The effects of electro-coagulation on sludge characteristics and fouling behavior were investigated. A batch-scale experiment was carried out to identify an optimum electric current condition for electro-MBR study, in which the electro-MBR and a traditional MBR were identically set for numerous comparisons. The average fouling rate was substantially reduced 7.8 fold resulting in no chemical cleaning requirements during the entire operation of the electro-MBR. Enhanced sludge compressibility and controlled growth of filamentous bacteria positively affected by electro-coagulation were also obtained in the electro-MBR. This paper suggests that fouling mitigation in electro-MBR can be attributed to two mechanisms: (i) charge neutralization and adsorption for soluble foulants; (ii) electro-chemical oxidation for bound foulants. Furthermore, we conclude that electro-coagulation can simultaneously alter morphology and microbial structure of sludge flocs to become more compressible with lower fouling tendency, which would be beneficial for the mitigation of membrane fouling in electro-MBR. [ABSTRACT FROM AUTHOR]

The purpose of this study is to identify differences in variations of contact time and number of electrode plates in electrocoagulation process on the decrease of total Coliforms in Bandung City hospital wastewater. An experimental research with factorial randomized design. The volume of wastewater sample to check the total Coliforms was a minimum of 100 ml, using 3 treatments and 6 repetitions. Data analysis used was two-way ANOVA test. The results showed that there was no significant difference between the number of plates (p = 0.269), contact time (p = 0.537), and the number of plates and contact time (p = 0.863) with the total Coliforms in electrocoagulation process. The use of 6 plates and 90 min contact time showed the best results in reducing total Coliforms, with effectiveness reaching 88.38%. This means that the concept is quite effective to use as a substitute for disinfectant. [ABSTRACT FROM AUTHOR]

Considerable amounts of produced water (PW) are usually accompanied with the production of oil. This study proposed a combination of electrocoagulation (EC) - electro- Fenton (EF) process for oxidation organic compounds in PW to reduce the chemical oxygen demand (COD) to below regulation limits. The PW used in this study was collected from oilfield in the Midland Oil Company. Pretreatment of the PW was conducted using batch EC technique with aluminum electrodes to eliminate the suspended and dissolved solids and to reduce the COD and treatment cost. Optimization of EC process revealed that optimum current density, pH, and reaction time were 7.83 mA/cm², 7.24, 20.40 minutes respectively. Under these conditions the COD removal percentage was 73.97% starting from initial COD of 1730 mg/l.Batch and continuous electro-Fenton processes were investigated using dimensionally stable anode Ti-RuO2/IrO2 and activated carbon fiber felt (ACFF) cathode. The effect of crucial process variables on COD removal efficiency was investigated using response surface methodology. A second order polynomial model equations were constructed and the results was analyzed by the analysis of variance (ANOVA). It was concluded that a combination of electrocoagulation followed by electro-Fenton process is effective for treating oilfield produced water and further improvement can be achieved by photo assisting the process. A total COR removal efficiency of 98% was achieved. [ABSTRACT FROM AUTHOR]

We in this study investigated a novel electrochemical approach combining electro-enzyme and electrocoagulation to precipitate bisphenol A (BPA) from water containing humic acid (HA). Horseradish peroxidase was immobilized on the graphite felt of Ti electrode as HRP-GF/Ti cathode, with aluminum plate anode establishing a pair of working electrodes. BPA was 100% removed and the reduction of total organic carbon (TOC) reached 95.1% after 20-min sequencing treatment with the current density of 2.3 mA/cm 2 . Real wastewater (TOC = 28.76 mg/L, BPA = 4.1 μg/L) also can achieve 94% BPA removal and 52% TOC reduction after sequencing treatment. Additionally, coupled electro-system with continuous flow only required energy of 0.016 kWh/m 3 to achieve simultaneous 90% BPA and 85% TOC removal. As indicated in the time-of-flight mass spectrometry and FTIR spectra, the electro-enzymatic process not only oxidized BPA into dimer and BPA-3,4-quinone, but also greatly altered the chemical and structural features of HA, where hydrophilic moieties (phenolic and alcohols) transformed into hydrophobic forms (ethers, quinone and aliphatic). These polymerized products were effectively separated from aquous solution during anodic electrocoagulation, leading to significant removal of BPA and TOC. Thus, the coupled process may provide a faster and less energy strategy to control certain emerging contaminants in water/wastewater treatment. [ABSTRACT FROM AUTHOR]

Heavy metals pollution has become a more serious environmental problem in the last several decades as a result releasing toxic materials into the environment. Various techniques such as physical, chemical, biological, advanced oxidation and electrochemical processes were used for the treatment of domestic, industrial and agricultural effluents. The commonly used conventional biological treatments processes are not only time consuming but also need large operational area. Accordingly, it seems that these methods are not cost-effective for effluent containing toxic elements. Advanced oxidation techniques result in high treatment cost and are generally used to obtain high purity grade water. The chemical coagulation technique is slow and generates large amount of sludge. Electrocoagulation is an electrochemical technique with many applications. This process has recently attracted attention as a potential technique for treating industrial wastewater due to its versatility and environmental compatibility. This process has been applied for the treatment of many kinds of wastewater such as landfill leachate, restaurant, carwash, slaughterhouse, textile, laundry, tannery, petroleum refinery wastewater and for removal of bacteria, arsenic, fluoride, pesticides and heavy metals from aqueous environments. The objective of the present manuscript is to review the potential of electrocoagulation process for the treatment of domestic, industrial and agricultural effluents, especially removal of heavy metals from aqueous environments. About 100 published studies (1977-2016) are reviewed in this paper. It is evident from the literature survey articles that electrocoagulation are the most frequently studied for the treatment of heavy metal wastewater. [ABSTRACT FROM AUTHOR]

An electrocoagulation flotation (ECF) process was used to remove selected nonsteroidal anti-inflammatory drugs (NSAIDs), specifically diclofenac, ibuprofen, and ketoprofen, from water. A cationic surfactant, cethyltrimethyl ammonium bromide (CTAB), was added to the solution as a collector and frother. Without the addition of the cationic surfactant, the removal of NSAIDs in a single-NSAID solution was in the range of 10–45%; it decreased to approximately 10% in multiple-NSAID systems. However, after adding a stoichiometric amount of CTAB, the removal of NSAIDs significantly improved in single-NSAID systems. For multiple-NSAID removal, the concentration of CTAB required to achieve ideal removal was equal to the sum of the molar concentrations of all the NSAIDs. In addition, a high current density produced smaller bubbles, thus enhanced the electro-flotation and achieved better removal performance. Removal of multiple-NSAIDs in actual hospital wastewater was significantly lower due to interference by oils and other hydrophobic substances. [ABSTRACT FROM AUTHOR]

Electrocoagulation using a Zn anode was applied for the first time to remove the organic load of a liquid effluent. Different operating conditions (pH, current density, distance between electrodes, nature of electrolyte and kind of cathode) were tested with synthetic phenolic wastewater, in order to optimise the process. Both the medium pH and the type of electrolyte that were used greatly affected the efficiency of the system, followed by the influence of the current density and the cathode material, in a lesser extent. The effect of the distance between electrodes was quite negligible. Furthermore, a sequence of fed-batch trials involving the electrodes reuse showed almost constant activity during the operation time. The optimum operating conditions achieved were initial pH of the effluent equal to 3.2, current density of 250 A/m 2 , distance between electrodes of 1.0 cm and 1.5 g/L of NaCl. Moreover, the Zn anode/stainless steel cathode pair revealed the most interesting results. These parameters led to 84.2% and 40.3% of total phenolic (TPh) content and chemical oxygen demand (COD) removal, respectively. In addition, the depuration of a filtered real olive mill effluent without NaCl addition achieved the abatement of up to 72.3% of TPh and 20.9% of COD. An energy consumption of 40 kW h/m 3 and 34 kW h/m 3 was observed for the treatment of the simulated and the real wastewater, respectively. Furthermore, the ecological impact of the treated effluent was detected by bio-luminescence techniques. This study shows the potentiality of the electrocoagulation process as a pre-treatment of other methods, namely the electrochemical oxidation, to ensure the legal limits values of the wastewater to be discharged into the aquatic environment regarding their organic load. [ABSTRACT FROM AUTHOR]

This research deals with the investigation of electrocoagulation (EC) treatment of wastewater from a dairy plant using aluminum electrodes. Electrolysis time, pH, current density and distance between electrodes were considered to assess the removal efficiency of chemical oxygen demand (COD), total solids (TS) and their fractions and turbidity. Samples were collected from the effluent of a dairy plant using a sampling methodology proportional to the flow. The treatments were applied according to design factorial of half fraction with two levels of treatments and 3 repetitions at the central point. The optimization of parameters for treating dairy industry effluent by electrocoagulation using aluminum electrodes showed that electric current application for 21 minutes, an initial sample pH near 5.0 and a current density of 61.6A m-2 resulted in a significant reduction in COD by 57%; removal of turbidity by 99%, removal of total suspended solids by 92% and volatile suspended solids by 97%; and a final treated effluent pH of approximately 10. Optimum operating condition was used for cost calculations show that operating cost is approximately 3.48R$ m-3. [ABSTRACT FROM AUTHOR]

Nanoscience is a field that has stood out in recent years. The accurate long-term health and environmental risks associated with these emerging materials are unknown. Therefore, this work investigated how to eliminate silver nanoparticles (AgNPs) from synthetic effluents by electrocoagulation (EC) due to the widespread use of this type of nanoparticle (NP) in industry and its potential inhibition power over microorganisms responsible for biological treatment in effluent treatment plants. Synthesized AgNPs were studied via four different routes by chemical reduction in aqueous solutions to simulate the chemical variations of a hypothetical industrial effluent, and efficiency conditions of the EC treatment were determined. All routes used silver nitrate as the source of silver ions, and two synthesis routes were studied with sodium citrate as a stabilizer. In route I, sodium citrate functioned simultaneously as the reducing agent and stabilizing agent, whereas route II used sodium borohydride as a reducing agent. Route III used d -glucose as the reducing agent and sodium pyrophosphate as the stabilizer; route IV used sodium pyrophosphate as the stabilizing agent and sodium borohydride as the reducing agent. The efficiency of the EC process of the different synthesized solutions was studied. For route I, after 85 min of treatment, a significant decrease in the plasmon resonance peak of the sample was observed, which reflects the efficiency in the mass reduction of AgNPs in the solution by 98.6%. In route II, after 12 min of EC, the absorbance results reached the detection limit of the measurement instrument, which indicates a minimum reduction of 99.9% of AgNPs in the solution. During the 4 min of treatment in route III, the absorbance intensities again reached the detection limit, which indicates a minimum reduction of 99.8%. In route IV, after 10 min of treatment, a minimum AgNP reduction of 99.9% was observed. Based on these results, it was possible to verify that the solutions containing citrate considerably increased the necessary times required to eliminate AgNPs from the synthesized effluent, whereas solutions free of this reagent showed better results on floc formation and, therefore, are best for the treatment. The elimination of AgNPs from effluents by EC proved effective for the studied routes. [ABSTRACT FROM AUTHOR]

Electrocoagulation (EC) treatment of 100 mg/L synthetic wastewater (SWW) containing humic acids was optimized (achieving 90% COD Mn and 80% DOC removal efficiencies), after which real peat bog drainage waters (PBDWs) from three northern Finnish peat bogs were also treated. High pollutant removal efficiencies were achieved: P tot , TS, and color could be removed completely, while N tot , COD Mn , and DOC/TOC removal efficiencies were in the range of 33–41%, 75–90%, and 62–75%, respectively. Al and Fe performed similarly as the anode material. Large scale experiments (1 m 3 ) using cold (T = 10–11 °C) PBDWs were also conducted successfully, with optimal treatment times of 60–120 min (applying current densities of 60–75 A/m 2 ). Residual values of Al and Fe (complete removal) were lower than their initial values in the EC-treated PBDWs. Electricity consumption and operational costs in optimum conditions were found to be low and similar for all the waters studied: 0.94 kWh/m 3 and 0.15 €/m 3 for SWW and 0.35–0.70 kWh/m 3 and 0.06–0.12 €/m 3 for the PBDWs (large-scale). Thus, e.g. solar cells could be considered as a power source for this EC application. In conclusion, EC treatment of PBDW containing humic substances was shown to be feasible. [ABSTRACT FROM AUTHOR]

In this study treatability of bilge water was investigated by electrochemical processes: electrocoagulation/electroflotation process and also the electro-fenton process as an indirect electrooxidation process. As the seawater is mixed into bilge water, the chloride content and the conductivity of bilge water are quite high, which is a great advantage in terms of electrochemical wastewater treatment. Treatability of bilge water by electrocoagulation/electroflotation process is investigated by using aluminum and iron electrodes in accordance with pH, time, temperature and current density. When the aluminum and iron electrodes are compared in electrocoagulation–electroflotation process, the results clearly showed that the aluminum electrodes were more efficient and as well as in a short period of time as 10 min. Chemical oxygen demand and oil–grease removal values obtained as 64.8% and 57% from Al and 36.2% and 12.5% from Fe, respectively. On the other hand by electro-fenton process, it was seen that higher removal efficiencies were obtained in comparison to the electrocoagulation method, with the COD and oil–grease removal being equal to 71% and 69%, respectively. The discharge standards specified by MARPOL were obtained by the electro-fenton process. When processes are analyzed in economically way, the electricity cost of electrocoagulation process by aluminum, iron and electro-fenton process was 0.54 $/m 3 , 0.53 $/m 3 , 0.51 $/m 3 , respectively. In addition, pseudo-second-order kinetic model was fitted for both COD and Oil&Grease removal in electrocoagulation process. [ABSTRACT FROM AUTHOR]

The goal of this research was the elimination of the chemical oxygen demand (COD), total organic carbon (TOC), color, and turbidity from the industrial wastewater from an industrial park by applying electrocoagulation (EC) and electrooxidation (EO) processes powered by solar cells. The EC process was carried out in a batch monopolar electrochemical cell; copper was used for the anode and cathode electrodes, with an area of 0.00125 m 2 , and solar cells supplied the system with 1–3 A of current intensity. The COD reduction was 80% at pH 2 and 89% at pH 4, and a removal efficiency of 97% and 91% of color and turbidity, respectively, were achieved; however, TOC reduction achieved was only 48%. In order to improve the removal of TOC, an EO treatment was applied after the EC process. The EO was carried out in batch cells using a boron-doped diamond (BDD) anode and a copper cathode. The maximum removal efficiency was 70.26% of TOC and 99.7% of COD, with EC + EO processes. Color and turbidity removal were 100% and 95%, respectively. Aside from the strong oxidation capability of the hydroxyl radicals generated, the presence of active chlorine in the solution contributed to COD removal via indirect oxidation. [ABSTRACT FROM AUTHOR]

This work studies the electrocoagulation (EC) process for the treatment of colored solutions of two dyes used in the textile industry: direct brown 2 (DB) and BF cibacete blue (CB) using aluminum electrodes in batch mode. Key EC parameters are investigated. The pH effect is found to be more important than the supporting electrolyte on the electrochemical process. The best EC efficiencies are as follows: for DB, 99.89% removal at 40 mg/L (pH 10,U= 12 V,tEC= 60 min); and for CB, 99.74% removal at 40 mg/L (pH 2.5,U= 12 V,tEC= 60 min). The power consumption is 16.56 and 17.04 kWh/m3for DB and CB, respectively. [ABSTRACT FROM PUBLISHER]