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Textile wastewater, laden with persistent dyes and non‐biodegradable organics, poses a challenge for treatment in common effluent treatment plants (CETPs) using conventional methods. Pre‐treatment of textile effluents is essential to ensure compatibility with CETPs. The present study employed three‐dimensional (3D) aluminum and graphite electrodes for a sequential electro‐coagulation and electro‐Fenton (EC + EF) process. An experimental plan of 25 experiments was constructed using Taguchi method. The combination resulted in high removal efficiencies: 99.91% for color, 93.20% for chemical oxygen demand (COD), and 91.75% for total organic carbon (TOC) for the operating parameters; for EC, current density (J): 20 mA/cm2, time (t): 45 min, speed of rotation (N): 55 rpm; and for EF, current density (J): 25 mA/cm2, time (t): 50 min, iron concentration: 40 mg/L. Post‐treatment, the wastewater exhibited an enhanced biodegradability index of 0.875, rendering it suitable for CETPs. There was an increase of 11% in the total energy consumption when energy spent during rotation and aeration at the time of EC and EF, respectively, were considered. This energy increases the cost and is not accounted for, in previous research. The energy consumption in kWh per g of COD removed at optimum condition for the hybrid treatment was 0.0314, which is lower than the energy consumption by other electrochemical processes employing plate electrodes. This indicates that 3D electrodes are more energy efficient than plate electrodes. Practitioner Points: Hybrid electrochemical processes can be used as pre‐treatment method for textile effluents.Three‐dimensional electrodes improve removal rates with lower energy consumption.Significant color, COD, and TOC abatement were noted post‐hybrid treatment of textile wastewater.Biodegradability of the textile effluent improves after the hybrid treatment. [ABSTRACT FROM AUTHOR]

The textile sector is considered as the 3rd largest source of water pollution and land degradation during 2020. 20% of the world's water pollution is linked with textile production and utilisation. Textile washing releases 14 million tons of microplastics, according to European Environmental Agency estimates. Wastewater Treatment Plant [WWTP] has declared everyday normal releases of more than 4 million MP particles because of its tiny size (<5 mm) and low thickness (<1.2 g/cm³). Electrochemistry for the removal of tinny pollutants is recognised as an efficient treatment mechanism. The main aim of this research paper is to identify the efficiency of electro-coagulation technology using Fe and Al as anode and cathode in microplastic removal from Thailand's textile industries. Results show the maximum 100% microplastic removal efficiency with pH 10 at a current density of 30 A/m² within 60 minutes of the current supply. This paper helps to understand the role of electro-coagulation in Thailand textile wastewater plants and adopt the best available technique for microplastic removal. [ABSTRACT FROM AUTHOR]

The treatment of stabilized leachates with high refractory organic matter content, which are over 10 years old, presents a challenge. This study explored the potential of electro-coagulation (EC) and electro-oxidation (EO) treatment systems to address this issue. The objective of this study was to investigate the phytotoxicity of the proposed treatment system on seed growth and examine possible relationships between phytotoxicity results and the characterization of leachates, effluents, soil, and radicles. Phytotoxicity tests were conducted on seeds of Lactuca sativa, Cucumis sativus, and Phaseolus vulgaris, using Inductively Coupled Plasma-Optical analysis. The evolution of organic matter was monitored by fractionating the chemical oxygen demand (COD) and humic substances. The biodegradability index increased from 0.094 in raw leachate to 0.26 and 0.48 with EC and EO, respectively. Removal rates of 82%, 86%, 99%, and 81% were achieved for COD, dissolved organic carbon, color, and ammoniacal nitrogen, respectively. The biodegradable COD increased from 26% in raw leachate to 39% in the EC process and 58% in the EO process effluent. The proposed treatment system successfully broke the aromatic structures of the humic substances present in the raw leachate, thereby increasing the content of biodegradable material. Phytotoxicity tests revealed that the proposed treatment system significantly reduced the phytotoxicity of the generated effluents. [ABSTRACT FROM AUTHOR]

Abstract Olive Mill Wastewater (OMWW) is produced in large quantities and contains high levels of nutrients that can be reused for irrigation, reducing the demand for freshwater resources. However, OMWW is phytotoxic and expensive to treat, making it important to develop more cost-effective treatment methods. This study aims to investigate an integrated detoxification treatment sequence consisting of acid precipitation, Fenton oxidation, and electrical coagulation to safely reuse OMWW for barley germination. Raw, treated and diluted OMWW (25% and 50% OMWW) were tested. The results showed that raw and diluted OMWW suppressed seed germination at all concentrations, while diluted treated OMWW enhanced seed germination and plant growth. In addition, treated OMWW (acid precipitation treatment) at 25% dilution reported 0% phytotoxicity significantly improved plant growth, where plant fresh weight (FW) reached 123.33 mg. Moreover, α-amylase, lipase, and protease enzyme activity confirmed the superior enhancement of barley growth parameters, where the highest enzyme activity value recoded 0.870 mg maltose/g FW. The integrated treatments reduced detoxification by 97.90% for total phenolic, 98.37% for total flavonoids, and 99.18% for total tannins. Reductions of around 95.78%, 60.00%, and 78.90% in total organic carbon, electric conductivity, and total solids, respectively, were achieved. A significant decrease in heavy metals was observed with removal ratios 98.64%, 94.80%, 96.88%, and 95.72% for Fe, Cu, Mn, and Zn, respectively. Seedling Vigor Index as an indicator of crop productivity was successfully predicted using neural network modeling. Therefore, the applied method can be used as a fertilizer to support plant growth and reduce fertilization costs.

Olive Mill Wastewater (OMWW) is produced in large quantities and contains high levels of nutrients that can be reused for irrigation, reducing the demand for freshwater resources. However, OMWW is phytotoxic and expensive to treat, making it important to develop more cost-effective treatment methods. This study aims to investigate an integrated detoxification treatment sequence consisting of acid precipitation, Fenton oxidation, and electrical coagulation to safely reuse OMWW for barley germination. Raw, treated and diluted OMWW (25% and 50% OMWW) were tested. The results showed that raw and diluted OMWW suppressed seed germination at all concentrations, while diluted treated OMWW enhanced seed germination and plant growth. In addition, treated OMWW (acid precipitation treatment) at 25% dilution reported 0% phytotoxicity significantly improved plant growth, where plant fresh weight (FW) reached 123.33 mg. Moreover, α-amylase, lipase, and protease enzyme activity confirmed the superior enhancement of barley growth parameters, where the highest enzyme activity value recoded 0.870 mg maltose/g FW. The integrated treatments reduced detoxification by 97.90% for total phenolic, 98.37% for total flavonoids, and 99.18% for total tannins. Reductions of around 95.78%, 60.00%, and 78.90% in total organic carbon, electric conductivity, and total solids, respectively, were achieved. A significant decrease in heavy metals was observed with removal ratios 98.64%, 94.80%, 96.88%, and 95.72% for Fe, Cu, Mn, and Zn, respectively. Seedling Vigor Index as an indicator of crop productivity was successfully predicted using neural network modeling. Therefore, the applied method can be used as a fertilizer to support plant growth and reduce fertilization costs. [ABSTRACT FROM AUTHOR]

Fox-Fordyce disease is known to be a chronic and uncommon skin disease that affects regions with a high density of apocrine glands. This disease affects women between 13 and 35 years. It may be considered that hormonal imbalance play a key role in the pathogenesis, but the exact cause is still unclear.il] Other cause may be a history of trauma caused by laser hair removal may be a trigger tf this disease. Pruritus can be present and it may be caused by the extravasion tf glandular content. Due to the severe itch, the patient may develop infection or hiperpigmentation in the affected regions. The clinical features are monomorphic, dome-shaped, skin-colored, follicular papules that invole the axillary, pubic, perineal and areolar areas, pruritus and hair loss in the affected regions. Histopathology is in many cases non-specific.[2] Terapeutic options are varied and may include topical steroids, topical retinoids, topical clindamycin, topical calcineurin inhibitors, oral retinoids, oral contraceptives, intradermal infiltration cf botulinum toxin or triam-cinolone, excision, electrocoagulation and laser. [ABSTRACT FROM AUTHOR]

Chemically, Arsenic is one of the double-edged sword element distributed ubiquitously in nature. Low concentration of arsenic is used to treat leukaemia where as the high concentration of arsenic intake in human body leads to critical diseases such as skin diseases, cancer, blackfoot disease, hypertension, neurological effect, DNA damage and others. Chronic exposure may lead to coma and death. This peer review provides an overview about the distribution of arsenic species in rock, mining, and their pH dependent mobility that are found in aqueous body. The study reviews information among the various routes of arsenic exposure, their toxicity mechanisms, and a variety of total arsenic concentration detection process such as spectroscopic techniques, kit detection. The heart context of this review covers best arsenic removal techniques such as coagulation, absorption, oxidation, osmosis, electro-coagulation and others reputed techniques. [ABSTRACT FROM AUTHOR]

In this study, a batch-scale electrocoagulation (EC) reactor with fixed aluminium electrodes was examined, for the removal of hexavalent chromium [Cr(VI)] from synthetic wastewater. The effects of operating parameters namely current density, initial Cr(VI) concentration and initial pH on the performance of the EC process were established. Taguchi method (L9 orthogonal array (OA) with 3-factors in 3-levels) was used to obtain the optimum working condition for the operating parameters for maximum Cr(VI) removal. The performance characteristics i.e. signal-to-noise (S–N) ratio (the larger-the-better) and analysis of variance (ANOVA) were considered to compare the relative greatness of a factor's effect on the response parameter. The optimum working condition was obtained at initial Cr(VI) concentration: 15 mg/L; current density: 49.3 mA/cm2 and initial pH: 5. Increase in current density led to enhanced Cr(VI) removal. On the contrary, the removal efficiency was inversely proportional to the initial Cr(VI) concentration. The applicability of the additive model was proven by the high R2 value (0.998) and lower value (0.6068) of Root Mean Square Error (RMSE). The ANOVA results suggested that the current density, initial Cr(VI) concentration and initial pH had a notable influence on the Cr(VI) removal, with contributions of 2.35%, 78.68% and 18.91%, respectively. At the optimum condition, an X-ray fluorescence (XRF) analysis confirmed the presence of Al(OH)3 and Cr(OH)3 precipitate in the sludge sample, confirming the removal of Cr(VI). The total operational cost (OC) was calculated as $10.77/m3, at optimum conditions. [ABSTRACT FROM AUTHOR]

The separation performance, energy demand, and operating costs of electro-coagulation (EC) are compared to conventional chemical coagulation for oil–water separation using a simulated oil-and gas-produced water matrix. An iron-based chemical coagulant and sacrificial iron electrodes are evaluated. Effluent turbidity, chemical oxygen demand (COD), total organic carbon (TOC), and oil and grease (O&G) removal were determined for various coagulant concentrations and reaction times and current densities. Chemical coagulation produced superior turbidity removal when scaled by the total iron dose. At lower iron doses (

The treatment of stabilized leachates with high refractory organic matter content, which are over 10 years old, presents a challenge. This study explored the potential of electro-coagulation (EC) and electro-oxidation (EO) treatment systems to address this issue. The objective of this study was to investigate the phytotoxicity of the proposed treatment system on seed growth and examine possible relationships between phytotoxicity results and the characterization of leachates, effluents, soil, and radicles. Phytotoxicity tests were conducted on seeds of Lactuca sativa, Cucumis sativus, and Phaseolus vulgaris, using Inductively Coupled Plasma-Optical analysis. The evolution of organic matter was monitored by fractionating the chemical oxygen demand (COD) and humic substances. The biodegradability index increased from 0.094 in raw leachate to 0.26 and 0.48 with EC and EO, respectively. Removal rates of 82%, 86%, 99%, and 81% were achieved for COD, dissolved organic carbon, color, and ammoniacal nitrogen, respectively. The biodegradable COD increased from 26% in raw leachate to 39% in the EC process and 58% in the EO process effluent. The proposed treatment system successfully broke the aromatic structures of the humic substances present in the raw leachate, thereby increasing the content of biodegradable material. Phytotoxicity tests revealed that the proposed treatment system significantly reduced the phytotoxicity of the generated effluents.

This paper aims to comprehend the sensitivity effect of the electrode density combined with the total suspended solids on the improvement of the turbidity' removal. To this extent, three electro-coagulation lab-scale reactors (300 mm in length, 100 mm in width and 350 mm in height) equipped with aluminium made electrodes have been built to conduct the experiments with a test volume of 9 L. Consequently, the results have revealed that the removal efficiencies of chemical oxygen demand, total suspended solids, and turbidity are 54.65 %, 71.93% and 34.27% respectively for the reactor No.1. Regarding reactor No.2, the chemical oxygen demand, the total suspended solids, and the Turbidity's removal efficiency are 51.24%, 65.24% and 47.13%, respectively. Finally, the removal efficiencies in reactor No.3 are 54.65 %, 71.93% and 34.27%, respectively, for the chemical oxygen demand, the total suspended solids and the Turbidity, which led to considering implementing a full-scale electrocoagulation process in El Kerma wastewater treatment plant. Moreover, the results obtained have allowed developing statistically a quadratic polynomial model to describe the effluent turbidity. The model outcomes have showed an acceptable coefficient of determination with a significant corresponding probability of < 0.05 regarding the electrode density. [ABSTRACT FROM AUTHOR]

This paper describes observations made on studies carried in laboratory trials by using electro-coagulation process using iron electrodes. The purpose of this study is to present the iron electrode-based EC procedure, its superiority over other technologies used for removing arsenic from ground water and surface water. In order to reduce arsenic (As), it was also necessary to understand the basics of the electrochemical process (EC) and the significance of its operating conditions, such as anode materials, applied voltage, pH and anode distance. At different concentration of Arsenic (500 ppb, 200 ppb & 100 ppb) it was observed that with the higher concentration i.e. 500 ppb there is faster decrease in arsenic concentration at 6.5 pH. While, when using different current density 0.5 A & 1.0 A at (12V) almost same results were obtained i.e. arsenic removal took place in same time duration at a pH range of 3.5 to 6.5. It was also observed that arsenic concentration decreases with electrode spacing, size of electrodes and contact time of treatment. [ABSTRACT FROM AUTHOR]

In order to achieve considerable generation of free radicals during electro-coagulation (EC) process, EC with air breathing cathode (EC-ABC) was designed to allow for the coexistence of electro-Fenton (EF) and EC functions. This EC-EF-ABC synergetic system allows for both in-situ free radicals and adsorptive flocs generation in an undivided electrolytic cell. The yield of hydroxyl radicals and adsorptive flocs were quantified for accurate mechanism analysis. The control mechanism of the transition from EF to EC function during EC-ABC system was investigated. The air cathode material was studied and optimized to obtain high hydroxyl radical generation. The influences of both dissolved oxygen (DO) and pH condition on hydroxyl radical and flocs generation were studied. Whiles the latter was found to dominate the successive EF and EC functions, and further controls the hydroxyl radicals and flocs yield, the former only has a dominant effect on the hydroxyl radical yield. The adsorptive iron (oxy)hydroxide flocs' structure was also found to be fully depend on the DO condition. The control mechanism of initial pH and DO condition on radical and flocs generation was simplified as a 'Sudoku-like' relationship. The optimized initial pH and DO condition was studied to maximize the generation of hydroxyl radicals and adsorptive flocs. The design of EC-ABC process could have both advanced oxidation and adsorption abilities for wastewater pollutant removal. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract The rapid growth in the world population and fast developing industrialization have resulted in the acceleration of environmental pollution due to inadequate treatment methods accompanied by depletion of freshwater. The current research focused on the batch treatment of slaughter house wastewater (SWW) using the sequential three-step electro-coagulation (EC)–electro-oxidation (EO)–adsorption column (AC) processes and to compare the optimized values with the Omani National Standards for the application in irrigation purpose. The characterization of SWW before and after treatment was carried out by measuring chemical oxygen demand (COD), total organic carbon (TOC), total dissolved solids (TDS), turbidity, ammoniacal nitrogen (NH4–N) and conductivity. The optimization of the treatment processes was performed by response surface methodology (RSM) using central composite design. The maximum response obtained using EC unit was 99% with an operating cost of 2.78 USD/m3. The optimum treatment conditions in EC method were found to be 4.0 pH, electrolysis time of 30 min and electrolyte dosage of 5 g/L, with a current density of 18.11 mA/cm2. The maximum reduction in COD was 97% with an operating cost 0.32 USD/m3. The optimum COD reduction in EO method was 84.5% with an operating cost of 6.87 USD/m3. The optimum process parameters in the EO process were observed at 5.0 pH, 56.22 min electrolysis time with 5 g/L electrolyte dosage and a current density of 5 mA/cm2. The response shows 56.27% reduction in COD with an operating cost of 0.088 USD/m3. The study demonstrates that both EC and EO processes for the reduction of COD have a significant effect on the current density. Using adsorption column (AC) studies, the maximum reduction in COD was 76.8% with negligible operating cost. The optimum pH in the case of AC was 7.5, with an effluent flow rate of 8.63 mL/min, and the responses were found to be 76.067%, which indicates both pH and flow rate have significant effect on the % removal of COD.

Objectives : The effect of current density and contact time of electro-coagulation on membrane fouling was investigated. In order to elucidate the reason why the membrane fouling was reduced by electro-coagulation, the changes in the characteristics of activated sludge were examined before and after electro-coagulation. Methods : A series of electro-coagulation of activated sludge suspensions was carried out with current density of 2.5, 6, 12, 24 A/m2 for 0, 2, 6, 12 hours. After membrane filtrations of the activated sludge suspensions, the membrane fouling was compared before and after the electro-coagulation. Characteristic changes in the activated sludge were also analyzed quantitatively. Results and Discussion : Total fouling resistances (Rt) of the electro-coagulated activated sludge decreased as current density and contact time increased. For example, Rt decreased 15%, 63% and 86% under the condition of current density of 24 A/m2 and 2, 6, 12 hours of contact time. Particularly, three activated sludge suspensions having very different initial MLSS concentrations showed a similar reduction of Rt, indicating that the membrane fouling was reduced not dominantly by particulates but by soluble foulants. The MLSS increased as current density increased, but MLVSS had not changed accordingly, which means that inorganic solids such as Al(OH)3 and AlPO4 produced during electro-coagulation were the main reasons for the increased MLSS concentration. These solids could play a key role in the reduction of membrane fouling by means of a dynamic membrane. As current density increased, the EPS (extracellular polymeric substances) and soluble COD concentration were reduced, which led to the reduction of membrane fouling. Soluble TN and TP were not significantly changed after electro-coagulation. Conclusions : The fouling materials, particularly, EPS and soluble COD decreased as current density and contact time increased, which played a key role in the reduction of membrane fouling. In addition, the insoluble solids produced during the electro-coagulation would act as a dynamic membrane, which led to fouling reduction.

Background: Highly-concentrated phosphate and nitrate anions from sugarcane wastewater are often discharged into public waters without standardized treatments. This study assessed the effects of electrical coagulation, initial pH and reaction time in the removal of phosphate and nitrate pollutants. Methods: We used aluminum electrodes to remove the pollutants at Hakhim Farabi Agricultural and Industrial complex, Khuzestan Province, Iran. A septic tank was used for collecting water samples followed by measuring the pH, and the concentrations of phosphate and nitrate in the samples. The pH was set at 5, 7, 9 or 11. Six aluminum electrodes were placed perpendicular to the water flow and were connected to power in a single-polar method. They were used to assess the effects of pH changes, electrical power at 10 and 30 volts and the water retention time at 15, 30, 45 or 60 min. on the efficiency of the pollutants’ removal. Results: The results indicated that under equal retention time and varying pH values, as voltage increased from 10 to 30, the phosphate and nitrate removal increased progressively. It was further demonstrated that the maximum phosphate removal efficiency was achieved at pH7, while it declined at higher pH levels. The highest possible nitrate removal efficiency was achieved under alkaline pH levels. The overall results showed that at every pH and voltage, the percentage of phosphate and nitrate removal increased over time. Conclusion: This study demonstrated that electro-coagulation process is an appropriate and efficient method to remove phosphate and nitrate pollutants from sugarcane wastewaters.

Electrocoagulation is one of physical techniques in waste-water treatment that applicable for organic waste from aquaculture. This research aims to determining the effectivity of electro-coagulation technique with different electrical voltages and duration consumed in waste-water treatment. The treatments used two electrical voltage levels (6 dan 12V) and four different durations of time consumed (15, 30, 45, and 60 minutes). The result showed the changes of water quality. Decreasing values shown by Chemical Oxygen Demand (COD) at the voltage of 12V and duration of 60’ (in about 82,89%); orthophosphate at the voltage of 12V and duration of 45’ (67.49%); turbidity at the voltage of 12V and duration of 60’ (69.65%); color at the voltage of 12V and duration of 60’ (70.49%); Total Suspended Solid (TSS) at the voltage of 12V and duration of 15’ (31.90%); and Total Dissolved Solid (TDS) at the voltafe of 12V and duration of 60’ (10.31%). Furthermore, increasing values were found in parameters of free ammonia at the voltage of 12V and duration of 15’ (291.09%); ammonium at the viltyage of 12V and duration of 30’ (8.85%); and pH at the voltage of 6V and duration of 60’ (16%). The best treatment in improving water quality of treated organic waste from aquaculture was the voltage of 12V for 30 minutes.

To test the effect of electrolysis and microbial remediation technology in polluted river sediment, we explored the possibility of using electrolysis method to remove ammoniacal nitrogen–nitrogen (NH3–N), nitrate-nitrogen (NO3––N) and phosphate ions-phosphorous (PO43−–P). The electrolysis was carried out by double electrolysis reaction system with a pair of a titanium (Ti) mesh cathode, a Ti/Ti dioxide (TiO2)/Ruthenium (IV) oxide (RuO2) (RuO2–IrO2/Ti) mesh anode, and another pair of magnesium–aluminum (Mg–Al) alloy anode and a titanium mesh cathode placed within the sediment and overlying water. Results showed approximately 151.82 ± 21.69 mg total nitrogen (TN) in sediment was removed, which was five times than the non-electrolytic controls (30.21 ± 13.73 mg). Furthermore, NH3–N concentration in the sediment was substantially reduced (up to 2.9 times) compared to the non-electrolytic controls. Its efficiency lies in the electrolysis process, which may directly remove NH3–N through electrochemical oxidation and simultaneously produce oxygen which helps nitrifying bacteria to convert NH3–N into an NO3−–N by anode; moreover, electrolysis may directly remove NO3−–N in the overlying water through electrochemical reduction while simultaneously producing hydrogen electron donors for hydrogen autotrophic microorganisms, such as Hydrogenophohaga. This genus of hydrogen autotrophic denitrifying bacteria dominated the removal of NO3−–N by a cathode in electrolytic sediment. Electrolysis also reduced the PO43−–P through electro-coagulation since Mg2+ ions also produced a sacrificial Mg–Al alloy anode. This anode was used in conjunction with electro-deposition on a Ti mesh cathode to increase PO43−-P removal in the overlying water and sediment. This study verifies the benefits of electrolysis-driven bioremediation as a sustainable technology for the bioremediation of N and P polluted river sediment. [ABSTRACT FROM AUTHOR]

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The rapid growth in the world population and fast developing industrialization have resulted in the acceleration of environmental pollution due to inadequate treatment methods accompanied by depletion of freshwater. The current research focused on the batch treatment of slaughter house wastewater (SWW) using the sequential three-step electro-coagulation (EC)–electro-oxidation (EO)–adsorption column (AC) processes and to compare the optimized values with the Omani National Standards for the application in irrigation purpose. The characterization of SWW before and after treatment was carried out by measuring chemical oxygen demand (COD), total organic carbon (TOC), total dissolved solids (TDS), turbidity, ammoniacal nitrogen (NH4–N) and conductivity. The optimization of the treatment processes was performed by response surface methodology (RSM) using central composite design. The maximum response obtained using EC unit was 99% with an operating cost of 2.78 USD/m3. The optimum treatment conditions in EC method were found to be 4.0 pH, electrolysis time of 30 min and electrolyte dosage of 5 g/L, with a current density of 18.11 mA/cm2. The maximum reduction in COD was 97% with an operating cost 0.32 USD/m3. The optimum COD reduction in EO method was 84.5% with an operating cost of 6.87 USD/m3. The optimum process parameters in the EO process were observed at 5.0 pH, 56.22 min electrolysis time with 5 g/L electrolyte dosage and a current density of 5 mA/cm2. The response shows 56.27% reduction in COD with an operating cost of 0.088 USD/m3. The study demonstrates that both EC and EO processes for the reduction of COD have a significant effect on the current density. Using adsorption column (AC) studies, the maximum reduction in COD was 76.8% with negligible operating cost. The optimum pH in the case of AC was 7.5, with an effluent flow rate of 8.63 mL/min, and the responses were found to be 76.067%, which indicates both pH and flow rate have significant effect on the % removal of COD. [ABSTRACT FROM AUTHOR]

Regenerated cellulose (RC) was prepared from pineapple crown waste fiber (PCWF) with a yield of about 45 %. The RC was blended with hardwood pulp (HP) to improve the mechanical properties of the paper. The composite paper with improved tensile index from 16.87 ± 0.75 NN mm/g to 28.98 ± 1.2 NN mm/g and burst index from 0.974 ±0.083 kkPaPa mm22/g to 1.827 ±0.153 kkPaPa mm22/g was developed by blending 20 % RC with 80 % HP. It was calculated that the production of one tonne of RC generates about 130 m3 of wastewater and it can be recycled after treatment with electrocoagulation technique. After wastewater treatment, chemical oxygen demand (COD) was reduced 84.8 %, total suspended solid (TSS) by 95.6 %, total dissolved solids (TDS) by 30.4 %, and biochemical oxygen demand (BOD) by 95.8 %. Importantly, the recycling behavior by reusing/recycling the treated wastewater for the regeneration process was investigated and a yield of about 42 % of the RC was observed. [Display omitted] [ABSTRACT FROM AUTHOR]

Due to water scarcity and population growth the use of treated wastewater in agriculture has become more frequent. With this motivation, several technologies have been introduced for the treatment of wastewater. The present work aimed at the tertiary treatment of the polluted water of Tataouine sewage treatment plant (Tunisia) using three alternative processes, namely electro-coagulation (EC), electro-Fenton (EF), and advanced electro-oxidation (AEO). After 180 min, chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) abatement rates reached respectively 56% and 14% with sharp deterioration of germs by EC process, and 75% and 52% with complete degradation of germs when EF process was applied. On the other hand, with AEO process, abatement rates of COD and BOD5 were 92% and 57%, respectively, with complete degradation of germs. The economic study showed that the EF process is technically and economically the best of these alternatives for treatment of this wastewater.

Background: Highly-concentrated phosphate and nitrate anions from sugarcane wastewater are often discharged into public waters without standardized treatments. This study assessed the effects of electrical coagulation, initial pH and reaction time in the removal of phosphate and nitrate pollutants. Methods: We used aluminum electrodes to remove the pollutants at Hakhim Farabi Agricultural and Industrial complex, Khuzestan Province, Iran. A septic tank was used for collecting water samples followed by measuring the pH, and the concentrations of phosphate and nitrate in the samples. The pH was set at 5, 7, 9 or 11. Six aluminum electrodes were placed perpendicular to the water flow and were connected to power in a single-polar method. They were used to assess the effects of pH changes, electrical power at 10 and 30 volts and the water retention time at 15, 30, 45 or 60 min. on the efficiency of thep ollutants' removal. Results: The results indicated that under equal retention time and varying pH values, as voltage increased from 10 to 30, the phosphate and nitrate removal increased progressively. It was further demonstrated that the maximum phosphate removal efficiency was achieved at pH7, while it declined at higher pH levels. The highest possible nitrate removal efficiency was achieved under alkaline pH levels. The overall results showed that at every pH and voltage, the percentage of phosphate and nitrate removal increased over time. Conclusion: This study demonstrated that electro-coagulation process is an appropriate and efficient method to remove phosphate and nitrate pollutants from sugarcane wastewaters. [ABSTRACT FROM AUTHOR]

The reclamation of graywater for non-potable purposes has attained utmost importance, particularly in developing nations. The present research aimed to evaluate the optimal condition of electro-coagulation system in treatment of graywater and its reuse. Moreover, the study also evaluates the impact of major operating parameters on pollutant removal and anode dissolution. To achieve this, two-factor (voltage potential and time) and 5-level (− 1, − 0.5, 0, + 0.5, and + 1) full factorial design, based on response surface methodology (RSM) has been executed for the actual design. The data were acquired after conducting 20 experiments, as suggested by RSM (response surface methodology). Design Expert 12.0.8.0 software has been used to design mathematical model to obtain optimum condition (14 V and 47 min) at pH of 7.35, which provides experimental removal efficiency (75.6% chemical oxygen demand, 78.7% total dissolved solids, 93.4% turbidity, and 63.2% chloride) with minimal electrode consumption of 1.38 mg L−1. Adequacy of the model developed has been verified by ANOVA. The operating cost of treating graywater at the optimized condition obtained as 0.7 US$/kg COD. [ABSTRACT FROM AUTHOR]

The wastewater produced during tertiary oil recovery often contains a large amount of hydrolyzed polyacrylamide (HPAM), which is difficult to treat using conventional biological methods because of its high molecular weight and viscosity. Electrochemical methods are considered to be effective for the treatment of refractory wastewater. In this study, the electrochemical degradation of HPAM using several anode materials was investigated. The results show that the highest HPAM removal efficiency was obtained when iron was used as the anode. The effects of the reaction time, voltage, current density, electrode distance, initial pH, and temperature on the efficiency of HPAM removal were investigated using single-factor experiments, and the HPAM removal rate was found to depend most strongly on the reaction time, voltage, and initial pH. Based on these results, Box–Behnken design was used to optimize the electrochemical treatment of HPAM, and the optimal conditions for HPAM removal were determined to be the following: voltage = 7.6 V, pH = 4.7, and reaction time = 10.5 min. The optimal conditions were tested experimentally, and the HPAM removal efficiency was found to be 98.4%, which fell within the 95% confidence interval of the model results. Analysis of the degradation mechanism showed that HPAM removal occurred mainly via electro-coagulation, with a contribution rate of 83%, together with electro-oxidation, and that the degradation intermediates included ammonia and ethers. Therefore, this electrochemical technique is effective for treatment of wastewater containing HPAM. [ABSTRACT FROM AUTHOR]

The bio-inspired algorithms are versatile approaches that can be applied to a variety of problems. However, their efficiency is influenced by a multitude of characteristics such as quality of final solution, consumed computational resources, diversity management, convergence, complexity of the problem being solved. Consequently, the issue of choosing the best approach for a particular problem is a difficult task. In this work, the performance of two bio-inspired algorithms, Differential Evolution (an improved version) and Differential Search, is tested on an electro-coagulation process applied for removing chlorophyll a from the final effluent of aerated lagoons in a wastewater treatment plant. Based on a set of experimental data, a regression model was generated to determine the correlations between the process characteristics and the remained chlorophyll a. After that, a set of simulations using the two algorithms were performed with the goal of determining the optimal conditions leading to a minimization of chlorophyll a in two different cases: i) when the interval for the process parameters is the same with the experimental data and ii) when limits on the process parameters were imposed (as a mean to reduce the resources consumed). The results obtained indicated that the two algorithms are able to provide acceptable results. [ABSTRACT FROM AUTHOR]

The outbreaks of cyanobacterial blooms have caused severe threat to aquatic ecosystem and public health. In this work, electrochemical technology with RuO 2 /IrO 2 /Ti (RIT) or/and Al as anode for cyanobacterial bloom control and simultaneous water purification were studied. Compared with RIT-Al and Al electrodes, RIT exhibited the highest effects on bloom algae inactivation and inhibition of algae regrowth. Live/dead analysis, SEM, intracellular reactive oxygen species (ROS) and antioxidant system activities revealed that RIT could disintegrate bloom flocs and damage embedded algal cells due to high intensity of oxidation. With the lysis of cyanobacterial bloom, high content of intracellular compounds containing organic carbon, nitrogen and phosphorus released, necessitating water quality restoration. In the subsequent water purification process, RIT-Al overtook RIT and Al in removal of organic and nutrient pollutants due to the complex effects of electro-oxidation, coagulation, co-precipitation, electro-nitrification and electro-denitrification. Therefore, sequential electro-oxidation and electro-oxidation-coagulation process was an effective method for control cyanobacteria bloom and simultaneous removal of DOM, microcystin-LR (MC-LR), nitrogen and phosphorus, which is a promising technology. [Display omitted] • A sequential EO and EO-EC process were fabricated for efficient cyanobacteria bloom control and nutrient removal. • EO remove cyanobacterial bloom via floc disintegration, intracellular ROS formation and cell damage. • Cyanobacterial bloom disintegration by EO caused release of intracellular SCOD, TN and TP. • Nutrient was removed by electro-oxidation, coagulation, precipitation, nitrification and denitrification. [ABSTRACT FROM AUTHOR]

Efficient removal of chemical oxygen demand (COD) and ammonium-N (NH 4 +-N) is the key issue for treatment of old landfill leachate. In this study, a peroxodisulfate assisted electro-oxidation and electro-coagulation coupled system (POCS) adopting Ti/SnO 2 –Sb 2 O 3 /TiO 2 and Fe dual-anode was constructed for synergistic removal of COD and NH 4 +-N in old landfill leachate. Laboratory experiment results showed that with current density of 20 mA cm−2, initial pH value of 8.0 and peroxodisulfate (PDS) concentration of 60 mM, the POCS system can reach removal efficiencies of 84.2% for COD and 39.8% for NH 4 +-N. The POCS effectively reduced the complexity of macromolecular organics and avoided the need to add acid or base to adjust pH value. The residual NH 4 +-N could be effectively recovered through struvite precipitation with a 93.8% purity of the precipitate. [Display omitted] • PDS assisted electro-oxidation and electro-coagulation coupled system was constructed. • POCS effectively treated old leachate without adjusting pH. • 84.2% of COD and 88.2% of ammonium were eliminated by POCS and struvite process. [ABSTRACT FROM AUTHOR]

This paper demonstrates technique of water purification using electro-coagulation method. This system is composed of DC electric source 200 V 30 A connect to the anode and cathode terminals. The DC power supply can be received from utility or solar energy. The sample of raw water from reservoir is used to conduct experimental reaction with electrocoagulation system in order to improve water quality. The water purification experimental was implemented by batch processing with varying electrolysis time. The parameter of electro-coagulation and water quality parameters are collected such as electric voltage, electric current, water temperature, pH, dissolved oxygen (DO), total dissolved solid (TDS) and electro-conductivity. The result found that the water quality has improved with the standard of domestic water supply and also drinking water standard.

Due to water scarcity and population growth the use of treated wastewater in agriculture has become more frequent. With this motivation, several technologies have been introduced for the treatment of wastewater. The present work aimed at the tertiary treatment of the polluted water of Tataouine sewage treatment plant (Tunisia) using three alternative processes, namely electro-coagulation (EC), electro-Fenton (EF), and advanced electro-oxidation (AEO). After 180 min, chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) abatement rates reached respectively 56% and 14% with sharp deterioration of germs by EC process, and 75% and 52% with complete degradation of germs when EF process was applied. On the other hand, with AEO process, abatement rates of COD and BOD5 were 92% and 57%, respectively, with complete degradation of germs. The economic study showed that the EF process is technically and economically the best of these alternatives for treatment of this wastewater. [ABSTRACT FROM AUTHOR]

Abstract Global demand of palm oil and palm oil derivatives lead to generate a huge quantity of palm oil mill effluent (POME). A post treatment is an essential step to a polish biologically treated POME before final discharge. In this study, the performance of employing hydrogen peroxide to enhance electro coagulation process in polishing POME was investigated. Operational variables including current density, contact time, initial pH, and H 2 O 2 dosage were applied and optimized using Response Surface Methodology (RSM). An optimized condition of 40.21 mA/cm2 of current density, 45.67 min of contact time, initial pH of 4.4 and 0.5 g/L of H 2 O 2 was able to achieve removal of 71.3%, 96.8%, and 100% for Chemical Oxygen Demand (COD), colour, and Total Suspended Solid (TSS), respectively. The parameters of polished POME were found below discharge limits of 1000 mg/L and 400 mg/L for COD and TSS, respectively. The biodegradability of POME increased from 0.037 to 0.14 by electro-coagulation-peroxidation (ECP) process. Compared with electrocoagulation alone, employing ECP in polishing POME can reduce current density by 28.2% and reaction time by 30%. Graphical abstract Image Highlights • Electro-coagulation-peroxidation (ECP) was examined as a post treatment for Palm Oil Mill Effluent (POME). • The optimum treatment efficiency of 71.3%, 96.8%, and 100% for COD, colour, and TSS were obtained, respectively. • The optimum factors were current density 40.21 mA/cm2, contact time 45.67 minutes, initial pH of 4.4 and 0.5 g/L of H 2 O 2. • Employing ECP in polishing POME instead of EC alone can reduce current density by 28.2% and 30% of reaction time. [ABSTRACT FROM AUTHOR]

The separation performance, energy demand, and operating costs of electro-coagulation (EC) are compared to conventional chemical coagulation for oil–water separation using a simulated oil- and gas-produced water matrix. An iron-based chemical coagulant and sacrificial iron electrodes are evaluated. Effluent turbidity, chemical oxygen demand (COD), total organic carbon (TOC), and oil and grease (O&G) removal were determined for various coagulant concentrations and reaction times and current densities. Chemical coagulation produced superior turbidity removal when scaled by the total iron dose. At lower iron doses (

The greatest volume of by-products produced in oil and gas recovery operations is referred to as produced water and increasing environmental concerns and strict legislations on discharging it into the environment cause to more attention for focusing on degradation methods for treatment of produced water especially electrochemical technologies. This article provides an overview of electrochemical technologies for treating oily wastewater and produced water, including: electro-coagulation, electro-Fenton, electrochemical oxidation and electrochemical membrane reactor as a single stage and combination of these technologies as multi-stage treatment process. Many researchers have carried out experiments to examine the impact of various factors such as material (i.e, electrode material) and operational conditions (i.e., potential, current density, pH, electrode distance, and other factors) for organic elimination to obtain the high efficiency. Results of each method are reviewed and discussed according to these studies, comprehensively. Furthermore, several challenges need to be overcome and perspectives for future study are proposed for each method. [Display omitted] • Review of electrochemical techniques in treatment of produced water and Oily wastewater. • Review of effective operational parameters on electrochemical treatment efficiency. • Electro-oxidation provides a simple, viable and promising method among the electrochemical methods. • Coupling electrochemical methods with proper technologies enhances the treatment results. [ABSTRACT FROM AUTHOR]

To handle complex wastewater with limited biodegradability, hybrid treatment systems are necessary. The current study represents the combined effectiveness of sulfate-radical associated electro-chemical advanced oxidation process (SR-EAOP) and electro-coagulation (EC) for the treatment of stabilized landfill leachate. For SR-EAOP, Pt/Ti was employed as the anode and an iron plate as the cathode; while EC treatment was performed by switching the polarity. Hence, both electrochemical treatment was carried out in single reactor. Initially, the effects of pH, applied voltage, persulfate and Fe2+ dosage, on the performance of SR-EAOP was examined. Sulfate radical was generated in the electrolytic system via cathodic reduction of persulfate (PS) and ferrous (Fe2+) ion activation. Auxiliary processes such as anodic oxidation via Pt/Ti anode and indirect electro-chemical oxidation were also contributed for pollutant degradation. Combined process SR-EAOP followed by EC (SR-EAOP + EC) has better leachate treatment efficacy in comparison with EC + SR-EAOPs. The SR-EAOP + EC based combined treatment mechanism achieved an efficient COD reduction of 88.67% than that of EC + SR – EAOP process (74.51% COD reduction). Characterization studies have been carried out for post-treated dried-sludge using Field Emission scanning electron microscope (FE-SEM) and X-ray powder diffraction (XRD) techniques. The combined process treatment (SR-EAOP + EC) can be applied as pre-treatment for leachate decontamination. [Display omitted] • SR-EAOP + EC process is found effective for the treatment of landfill leachate. • Performance of SR-EAOP + EC process is much better than EC + SR-EAOP process. • Biodegradability of landfill leachate increased from 0.195 to 0.57 after the treatment. • SR-EAOP + EC can be applied as pre-treatment for landfill leachate. [ABSTRACT FROM AUTHOR]

Considering the lack of information on simultaneously removing multiple pharmaceuticals from water or wastewater by electrochemical methods, this study aimed to investigate the removal of multiple pharmaceuticals by electro-coagulation and electro-oxidation based on two types of electrodes (aluminum and graphite). The synthetic wastewater contained a nonsteroidal anti-inflammatory drug (diclofenac), a sulfonamide antibiotic (sulfamethoxazole) and a β-blocker (atenolol). The pharmaceutical removal with electro-oxidation was much higher than those with the electro-coagulation process, which was obtained from a five-cell graphite electrode system, while the removal of pharmaceuticals with aluminum electrodes was about 20% (20 µM). In the electro-coagulation system, pharmaceutical removal was mainly influenced by the solubility or hydrophilicity of the compound. In the electro-oxidation system, the removal mechanism was influenced by the dissociation status of the compounds, which are attracted to the anode due to electrostatic forces and have a higher mass transformation rate with the electro-oxidation process. Therefore, atenolol, which was undissociated, cannot adequately be eliminated by electro-oxidation, unless the electrode’s surface is large enough to increase the mass diffusion rate.

The Electro-Coagulated Thermal Waste (ECTW) sample of the impedance spectroscopy investigation for electrical modulus and conductivity are presented. Electrical properties via temperature and frequency dependent impedance spectroscopy were investigated. Real and imaginary parts of electrical modulus were measured at various frequencies and a related Cole-Cole plot was acquired as well. The surface resistivity of the ECTW was measured by the four-point probe measurement technique, yielding a relatively high surface resistivity. As a result of this study, an effective building shielding material, which is a cost effective alternative, is proposed. The activation energy values were calculated from the Arrhenius plots at different frequencies. The transition region in this plot may be attributed to activation of ionic conductivity at lower temperatures.

In this study, removal of methylene blue by electro-coagulation method using aluminum and iron electrodes was investigated. The influence of the operating parameters such as contact time, current density, anode type, inter-electrodes distance, initial and final pH and energy consumption rate was determined. Dye removal was increased with increases in solution pH, current density and contact time and then decreased for increase in initial dye concentration and electrodes distance. The results show that the electrochemical method has significant efficiency in removal of methylene blue, higher efficiency was observed for iron (Fe) electrode; namely 100% and 95.78% of dye was removed by iron and aluminum electrode; respectively, after 24 min contact time. For a given current density, the removal efficiency and energy consumption rate showed that iron electrode was superior to aluminum in removal of methylene blue. In the case of iron as anode type, the required energy for complete dye decolorization was 3.8 kWh/m3; for 98% dye removal, the required energy was observed to be 4.3kWh/m3 in the case of aluminum as anode type. In general, complete methylene blue can be removed at operating parameters condition of iron as anode, distance between electrodes of 1cm, solution pH of 9 and current density of 50 A/m2 for 24 min electro-coagulation time.

This study presents an integrated Electro-Oxidation/Electro-Coagulation/Electro-Reduction (EO/EC/ER) process for tertiary landfill leachate treatment. The influence of variables including leachate characteristics and operation conditions on the performance of EO/EC/ER process was evaluated. The removal mechanisms were explored by comparing results of anode, cathode, and bipolar electrode substitution experiments. The performance of the process in a scaled-up reactor was investigated to assure the feasibility of the process. Results showed that simultaneous removal of carbonaceous and nitrogenous pollutants was achieved under optimal conditions. Ammonia removal was due to the free chlorine generation of EO while organic matter degradation was achieved by both EO and EC processes. Nitrate removal was attributed to both ER and EC processes, with the higher removal achieved by ER process. In a scaled-up reactor, the EO/EC/ER process was able to remove 50–60% organic matter and 100% ammonia at charge of 1.5 Ah/L with energy consumption of 15 kW h/m 3 . Considering energy cost, the process is more efficient to meet the requirement of organic removal efficiency less than 70%. These results show the feasibility and potential of the EO/EC/ER process as an alternative tertiary treatment to achieve the simultaneous removal of organic matter, ammonia, nitrate, and color of leachate. [ABSTRACT FROM AUTHOR]

In this study, the removal of some heavy metals ions such as cadmium [Cd+2], nickel [Ni+2] and lead [Pb+2] from synthetic wastewater were investigated using a lab-scale electro-coagulation [EC] system which was constructed for this purpose. Aluminum and iron were adopted as selective electrodes in order to compare the results for which is the best efficiency. Operational circumstances parameters such as pH, current density, detention time, and inner electrodes distance were tested in order to know the optimal operation values for the removal efficiency. The results showed that the optimal operation conditions for the max removal efficiencies occur at pH (7), current density (12.5 mA/cm2), inner electrode distance (1cm) for both aluminum and iron electrodes, and the detention time is (150 min) for aluminum, and (120 min) for iron electrodes. The experimental results indicate that the aluminum electrodes are better than iron electrodes.

Personal care wastewater contains pharmaceuticals and personal care products (PPCPs). The compounds were in organic pollutants which have to be treated before water can be discharged. Electrochemical processes such as electro-coagulation and electro-oxidation were used to remove non-biodegradable in wastewater. Electro-coagulation as pretreatment using aluminum electrodes as anode and cathode. Electro-oxidation using Ti/Pt, and Ti/IrO2 as anode electrodes and variation of current 0,6 A, 0,7 A, 0,8 A and 1,0 A. Aluminum electrodes has effectiveness in removing COD, and TSS in electrocoagulation. Using aluminum electrodes remove COD, and TSS 76.1% (5.41 g) and 90.3% (6.10 g). Under initial pH, aluminum electrode does not cause a change in pH from initial pH (4.8-4.9). The removal efficiency of electrooxidation process using aluminum electrocoagulation effluent COD using Ti/Pt and Ti/IrO2 were 34,30% (1,55 g) and 39,71% (1,80 g). Increasing current when using Ti/IrO2 causes the COD removal rate to be more effective than using Ti/Pt. removal COD with 1.0 A gave the optimum COD removal were 34,30% (2,3 Ah/L; 1,55 g) with Ti/Pt, and 39,71% (2,3 Ah/L; 1,80 g) with Ti/IrO2 compared to 0,6 A (1,4 Ah/L), 0,7 A (1,6 Ah/L), and 0.8 A (1,9 Ah/L).

Background & Objectives: Discharging of wastewaters containing detergents either by manufacturers or through domestic and industrial usages has caused the incidence of serious environmental problems. Entering these materials in to the surface waters reduces the amount of dissolved oxygen in the water and causes unsightly environment and groundwater pollution that is always has been notified by environmental experts. Methods: This study focuses on the treatment of laundry wastewater containing phosphate, nitrate and COD using iron as sacrificial electrode by EC process. Various operating conditions such as pH (3, 4, 5, 6, 7, 9), distance between the electrode (3, 5, 10,15mm) and current density (3, 6,9,12 mA/cm2) were investigated. Results: Experimental results showed that pollutant removal efficiency varied by changing pH, distance between the electrodes and current density. According to the results, optimum operating conditions for the removal of phosphate, nitrate and COD, were current density of 12mA/cm2, pH of 7.0, distance between the electrodes equal to 10 mm with Fe electrodes. The removal efficiency of phosphate, nitrate and COD were showed 99.33%, 96.67% and 91.43%. Also Kinetic analysis indicates that the adsorption system obeys a second- order kinetic model. Conclusion: According to the results, the Fe electrodes have been achieved the high removal efficiency of phosphate, nitrate and COD by using electrocoagulation.

Globalization, industrialization, mining, and uncontrolled population growth have fostered a shortage of potable water. Therefore, it has become imperative to understand an effective and reasonable water purification technique. A renewed interest in electrocoagulation (EC) has been spurred by the search for reliable, cost-effective, water-treatment processes. This paper has elucidated a technical approach for getting rid of heavy metals and total suspended solids (TSS) from synthetic water using an aluminum electrode. The effect of operational parameters, such as current density, inter-electrode distance, operating time, and pH, were studied and evaluated for maximum efficiency. This study corroborates the correlation between current density and removal efficiency. Neutral pH and a low electrode gap have been found to aid the efficacy of the EC setup. The outcome indicates that a maximum TSS removal efficiency of 76.6% occurred at a current density of 5.3 mA/cm² during a contact time of 30 min. In the case of heavy metals remediation, 40 min of process time exhibited extremely reduced rates of 99%, 59.2%, and 82.1%, for Cu, Cr, and Zn, respectively. Moreover, kinetic study has also demonstrated that pollutants removal follows first-and second-order model with current density and EC time being dependent. [ABSTRACT FROM AUTHOR]

The article focuses on electro-coagulation (EC) method to eliminate whey proteins from waste water, and talks of use of aluminum electrodes, adsorption, and cleaning of dairy effluents.

This contribution reports a novel and cost efficient strategy for nickel ion removal from metal finishing effluents by electro-dissolution of scrap aluminium and iron sacrificial anodes. Electro-coagulation of effluent was carried out at 30 mA/cm current density for 60 min. The nickel ion concentration of electroplating effluent was analysed by Atomic Absorption Spectroscopy. SEM images of iron and aluminium scrap anodes were critically analysed. Parameters such as heavy metal removal, anode dissolution rate with respect to heavy metal removal, reaction kinetics and cost estimation have been elaborately studied. Electro-coagulation at 30 mA/cm for 60 min using iron and aluminium scrap anodes resulted in 95.9 and 94.1 % nickel ion reduction, respectively, with 0.0094 and 0.0053 g/ppm dissolution rates. The energy consumption for scrap aluminium and iron anodes was 0.0547 kWh/L. Loose internal bonding and spongy surface morphology of used metal scrap render high porosity and active surface area, enhancing reaction rate. Low cost and ready availability of waste scrap makes the process of electro-coagulation economically viable. Thus, the findings from this contribution point decisively at the superiority of waste metal scrap-based anodes for economic and environmentally sustainable heavy metal ion removal from metal finishing effluent. [ABSTRACT FROM AUTHOR]