Electrocoagulation Treatment Research Articles

Poultry Slaughterhouse Wastewater Treatment Using an Integrated Biological and Electrocoagulation Treatment System: Process Optimisation Using Response Surface Methodology

The feasibility of a biological (EcoflushTM) and/or electrocoagulation (EC) treatment system in removing chemical oxygen demand (COD) and fats, oils, and grease (FOG) from poultry slaughterhouse wastewater (PSW) were studied. The response surface methodology (RSM) was used to identify the optimum operating condition for EC and its integration with EcoflushTM as a pre-treatment for the removal of lipids. The optimum operating conditions were obtained at a pH of 3.05, a current density of 66.9 A/m2, 74-min of treatment time, and without Ecoflush™. These conditions produced a high-quality clarified effluent after 92.4% COD reduction and 99% FOG reduction. The treatment with EcoflushTM only resulted in 85–99% FOG reduction, 20–50% COD reduction, and odourless effluent. However, the combination of both processes (EcoflushTM and EC) did not yield a significant difference (F test, p > 0.05) when compared to the performance of EC alone. Despite the low removal percentages of nitrogen and phosphorus, the present study proved that EC is an effective method for the removal of COD and FOG, rendering an effluent that meets the permissible discharge standards for the City of Cape Town. The novel Ecoflush™ also proved to be very efficient in the removal of FOG from PSW.

Paper industry wastewater treatment by electrocoagulation and aspect of sludge management

The paper production process comprises various manufacturing steps and generates an enormous amount of effluent, which consists of a large variety of contaminated chemicals. The higher color and chemical oxygen demand (COD) of the wastewater create a negative effect on all living forms and the natural environment. Electrocoagulation is a versatile process for the elimination of color and COD content from wastewater. In this study, the EC treatment has been used to identify the ideal conditions using several process variables such as pH, current density, time, and the dose of electrolyte. COD and color were reduced by up to 68% and 94%, respectively. Afterward, the treated water was compared with the standards of the world health organization (WHO) and the central pollution control board (CPCB) to find out the suitability of treated water for reuse for farming purposes. Germination tests of mung beans were conducted, and it was observed that the EC treated water is suitable for irrigation. The corrosion rate of mild steel was determined to be 2.85 mils/year, which has shown the short life span of mild steel electrodes. Furthermore, sludge produced by the EC process was analyzed and characterized for physicochemical analyses by using a variety of analytical techniques. The 69.93% iron content of the sludge was also recovered using the acid digestion method. After the physicochemical analyses, it was observed that sludge could also be utilized as a compelling supplement for plant growth, energy recovery, and industrial applications. According to this study, treated water could be a powerful alternative for reducing freshwater consumption in agricultural areas and increasing water availability in water-scarce areas. Effect of operating parameters on electrocoagulation treatment of pulp and paper industry wastewater, treated water and sludge management. • The higher COD and color 68% and 94%, respectively, were removed from wastewater by using EC treatment. • The greater removal of pollutants occurred at a near neutral pH. • It was observed that there was an encouraging improvement in the biodegradability index of wastewater after EC process. • Treated water is found to be suitable for reuse in agriculture. • The produced sludge could be a compelling supplement for plant growth, energy recovery, and industrial applications.

Boron removal from synthetic brines and oilfield produced waters using aluminum electrocoagulation

High boron (B) levels in oil and gas produced waters prevent its beneficial reuse as irrigation water without proper treatment. Aluminum (Al) electrocoagulation (EC) is a promising technology for B removal, but further research and development is needed to optimize EC for use in removing B from produced waters. To this end, B removal by adsorption onto insoluble aluminum hydroxide solids, generated by EC in simulated brines (up to 50,000 mg/L NaCl) and real oilfield produced waters, was studied. B removal during EC was greater than when aluminum hydroxide solids formed by EC were subsequently exposed to B containing solutions. Working parameters affecting B removal during the EC process, including current, total dissolved solid (TDS), temperature, pH, scale-forming cations and organic matter, were investigated to explore ways to achieve higher B removal. Boron removal increased with increased current loading and time, and with the concomitant increased Al solids concentration. However, too high a current loading limited B removal because of a change in the structure of the aluminum hydroxide solids. Higher TDS decreased B removal slightly, but lower TDS concentrations limited the use of higher current loadings. Temperature increased during EC treatment, particularly at higher current loadings, and this inhibited B removal due to an accelerated aggregation of amorphous Al solids into larger, denser, and presumably more crystalline particles. The best B removal occurred at pH 8, corresponding to a slightly positive zeta potential for aluminum hydroxide and a small but significant fraction of negatively charged B species. Scale-forming cations such as Ba2+ and Sr2+ had no obvious effect on the EC process. The presence of high concentrations of Mg2+ and Ca2+ resulted in low bulk pH values during the EC process and greater formation of solid products, but B removal did not decrease during a pH-controlled (pH = 8) EC process with these divalent cations present. Two produced water samples collected from oilfields in Kansas, US were treated using EC for 1 h, resulting in up to ~70 % B removal from solution with a current loading of 6.67 A/L, and up to 78 % with 13.33 A/L.

Leachate post-treatment by electrocoagulation process: Effect of polarity switching and anode-to-cathode surface area

In the electrocoagulation process, passivation or corrosion of the electrodes is one of the biggest challenges that cause a drop in treatment effectiveness. In this study, the effect of polarity switching was investigated, for the first time, in an attempt to enhance electrocoagulation treatment's ability to remove chemical oxygen demand (COD) and color from pretreated landfill leachate. Moreover, the ratio of the anode to cathode surface area and rotating electrode were examined in light of experimental results. The effect of different parameters, including the stirring speed, initial leachate pH, electrical current density, anode to cathode surface area ratio, and polarity switching time on system efficiency, was evaluated using the one-factor-at-a-time (OFAT) classical method. According to the results, polarity switching resulted in an almost 18% increase in COD removal, 14% increase in color removal, 13% decrease in electrical energy consumption (EEC), 51% decrease in the specific sludge production (TSS/COD), and improved electrode performance compared to non-polarity switching mode. The findings of this research showed the highest COD and color removal efficiencies, which were 34% and 67%, respectively, in a 120 min period, a stirring speed of 135 rpm, the initial leachate pH of 9, the current density of 14.4 mA/cm2, the anode/cathode surface ratio of 0.35, and the polarity switching time of 300 s.

Photovoltaic-driven electrochemical remediation of drilling fluid wastewater with simultaneous hydrogen production.

In this work, we studied the application of photovoltaic solar energy for driving the electrochemical processes of electrocoagulation and electrooxidation to remediate drilling fluid wastewater, and simultaneously harvest energy in the form of electrolytic hydrogen gas produced at the cathode. The electrocoagulation was performed with sacrificial aluminium electrodes and electrooxidation with dimensionally stable boron-doped diamond electrodes in batch-wise and continuously operated mode, and their efficiency in both pollutants removal and hydrogen gas production was elucidated. The parameters affecting the efficiency of the applied electrochemical processes, such as applied current density, pH, electroprocessing time and flow rate, were investigated. The electrochemical processing was monitored by measuring the chemical oxygen demand (COD) of treated wastewater. The electrocoagulation treatment conducted with current densities of 30, 60 and 90 mA/cm2 reduced the wastewater COD by about 67%, whereas the electrooxidation treatment at the same conditions yielded a COD removal of over 95%. The amount of produced hydrogen was 171 L/g COD removed from treated wastewater.

Optimization of the Electrocoagulation Process with Aluminum Electrodes for Rainwater Treatment

Rainwater collected in the Toluca region of Mexico with a pH of 6.25 was treated with an electrochemical process, and the efficiency of two supporting electrolytes were compared, one food grade (sea salt) and the other reagent grade (sodium sulfate). In the first stage, rainwater was characterized to detect the COD content, turbidity, metals such as zinc, iron, aluminum, and lead. Electrocoagulation treatment was performed with an electrochemical cell using aluminum electrodes to study the effect on COD and turbidity, as well as the removal of heavy metals present. The results obtained with response surface methodology and a central composite design reveal that the optimal conditions of the electrocoagulation treatment were a current density of 3.26 mA/cm2 and a time of 11.38 min. Using sodium sulfate, the percentage of turbidity removal is 99.27% and COD 70.83%. The use of sea salt as a support electrolyte in these conditions allowed the removal of COD at 100%, turbidity at 100%, and Al 100%, Mn 84.29%, Zn 97.97%, Pb 46%, Fe 21%. Energy costs that are low lead to proven savings when using this system, indicating that this treatment is an option to both improve rainwater conditions and be able to make use of it safely.

Electrochemical Formation of Aluminum Coagulants for Dairy Wastewater Treatment

Researches of chemical-technological parameters of electrochemical production of aluminum-based coagulants for electrocoagulation wastewater treatment of milk processing enterprises have been carried out. The impact of pH and the timing of the electrocoagulation process was studied in two cases of the implementation of the technological process: with the addition of an alkaline additive before and after the electrocoagulation treatment. The mechanism of the coagulation action of aluminum compounds formed as a result of electrocoagulation has been studied. It has been established that the addition of an alkaline additive after electrocoagulation is more effective. At the same time, the degree of wastewater treatment remains quite high. This will ensure energy savings and will positively affect the environmental and economic assessment of the technology.

Nanostructured electrochemical sensor applied to the electrocoagulation of arsenite in WWTP effluent

A sensitive electroanalytical method for the determination of arsenite, based on a heterostructure of aminated multiwalled carbon nanotubes and gold nanoparticles, was applied in an electrocoagulation (EC) treatment for the elimination of arsenite. A sensitive quantitative response was obtained in the determination of As3+ in a secondary effluent from a wastewater treatment plant from Santiago (Chile). The preconcentration stage was optimized through a Central Composite Face design, and the most sensitive peak current was obtained at 200 s and −600 mV of time and accumulation potential, respectively, after a differential pulse voltammetry sweep. Electroanalytical determination was possible in an interval between 42.89 and 170.00 μg L−1 with a detection limit of 0.39 μg L−1, obtaining recoveries over 99.1%. The developed method was successfully applied in an electrocoagulation treatment to remove 250 μg L−1 of arsenite from a polluted effluent in a batch system. Complete arsenite removal was achieved using a steel EC system with a current density of 6.0 mA cm−2 in less than 3 min of treatment.

How effective aerated continuous electrocoagulation can be for tetracycline removal from river water using aluminium electrodes?

The study assessed the effects of aeration on continuous electrocoagulation (EC) for tetracycline (TCL) removal from river water. Influence of hydraulic retention time (HRT) and initial drug concentration on treatment efficiency was tested. Best conditions for continuous EC operation were 12 min HRT, electrode spacing 2 cm, 9 V, and Al–Al electrode combination. Highest COD removal with non-aerated EC was 59.4% at 1 mg L−1 initial TCL concentration and further increasing TCL concentration decreased COD removal efficiency. Maximum TCL removal was 66.6% at 10 mg L−1 initial TCL concentration with non-aerated EC. Aerated EC enhanced COD and TCL removal to 61.4% and 71.5%, respectively. In XRD and FTIR spectra no new peaks were detected following EC treatment. XRD, FTIR and FESEM-EDS data supported that significant removal of TCL occurred by charge neutralization, entrapment, adsorption and precipitation driven by Al (OH)3 flocs. Pseudo-second order reaction rate constants explained the kinetics of TCL removal from river water. Sludge volume produced with continuous mode EC non-aerated and aerated EC was 31 cm3 and 39 cm3, respectively. Operating cost was estimated to 0.018 US$/m3 for non-aerated EC and 0.025 US$/m3 for aerated EC. EC can be augmented by aeration for enhanced removal of TCL from river water.

Treatment of sugar processing industry wastewater using copper electrode by electrocoagulation: Performance and economic study

This paper demonstrates the use of copper electrode for the treatment of sugar processing industry wastewater (SPIW) in terms of chemical oxygen demand (COD) by applying electrocoagulation (EC) method. EC process was carried out in batch mode with electrode effective area of 0.0112 m2, supplied current intensity (CI) of 44.64 A/m2 - 223.21 A/m2, electrode gap (EG) of 0.5–2.5 cm, electrolyte (NaCl) dose (ED) of 0.5–2.5 g/L to treat SPIW with initial chemical oxygen demand (COD) of 6000 mg/L. The maximum COD removal 73% of SPIW is achieved at optimized condition of SPIW pH: 7, CI: 89.28 A/m2, EG: 1.5 cm & ED: 1.5 g/L. Sludge and scum generated during EC process were characterized by FTIR, TGA/DTA/DTG, proximate & ultimate analysis to find its applicability and their disposal. Additionally, economic study of EC treatment process at optimum condition suggest treatment cost was 11.2 US$/m3 and it indicate economic results as comparison to other available treatment processes.

A comparative study of electrocoagulation treatment with iron, aluminum and zinc electrodes for selenium removal from flour production wastewater

Electrocoagulation (EC) using iron (Fe), zinc (Zn) and aluminum (Al) electrodes was comparatively applied in the treatment of selenium (Se) in flour production (FP) wastewater. It was indicated that EC treatment with Fe anode obtained highest removal efficiency (79.1%) for Se in the 90 min treatment in the comparative study, which could be attributed to the superior adsorption capacity of in-situ generated iron flocs. Removal of Se resulted from electrodeposition and adsorption to in-situ generated flocs in EC treatment, and the operational conditions significantly influenced the Se removal performance in this work. The results showed the acidic condition and higher current density favored EC treatment on Se removal, EC removed up to 97.8% of Se at pH 4 under 15 mA cm−2, whereas it obtained 83.5% and 50.4% of removal efficiency at pH 7 and 10, respectively. There was competitive adsorption in the process of selenium removal, as the in-situ generated flocs effectively removed 35.6% of humic acid-like (HA-like) substance in FP wastewater after 90 min treatment. The FTIR results showed that HA-like substance mainly contained the protein water hydrogen bond, carboxylate COO antisymmetric stretching and other functional groups. Through the analysis of existence of Se in flocs and wastewater, it can be found that approximately 2.8%–3.92% of Se was removed by electrodeposition process. This study illustrated the Se removal mechanism and provided constructive suggestion for food manufacturing to the metal removal and utilization of advanced treatment.

Electrocoagulation process for greywater treatment: Statistical modeling, optimization, cost analysis and sludge management

The present study investigates the removal of greywater pollutants such as COD, BOD, nitrate, and phosphate using the electrocoagulation treatment process. The influence of operating parameters such as current density (CD) (1–5 A/m2), contact time (CT) (10–90 min), and initial pH (3–11) of the solution was investigated using aluminum electrode. The results demonstrate that 70% COD removal, 87.5% BOD removal, 82.7% nitrate removal, and 84.7% phosphate removal is achieved at optimum operating condition (CD = 3 A/m2, CT = 60 min, and pH = 7, energy consumption = 0.153 kWhm−3, and operating cost = 0.114 US$m−3). The kinetics study analysis confirms that the electrocoagulation process follows pseudo-first-order kinetics model. The combination of response surface methodology (RSM) and artificial neural network (ANN) based statistical models were employed to optimize the electrocoagulation process parameters as well as to accomplish the individual limitations. The correlation coefficient value closer to ∼ 1 and lower error governs the feasibility of the developed models. The results exhibited that, the ANN model had a higher R2 and a lower MSE value than the RSM model, indicating that ANN is better at predicting process output than RSM, although RSM appropriately predicts process parameter interaction and its relevance. The study found that using a combinational approach to represent the electrocoagulation process for greywater treatment is more effective.

Two‐Phase Electrocoagulation of Perfumes and the Analytical Approach for Investigation of the Odor‐Active Compound Changes

AbstractIn this study, a 2‐phase electrocoagulation (EC) system has been applied to treat odor active compounds in perfume extracts. The system employed an electrochemical cell using two aluminium electrodes and 2‐phase electrolyte containing hexane, NaCl(aq) and the perfume compounds. This approach allowed electrochemical reaction of the compounds with the subsequent changes of their profiles in the extracts. The volatile compounds in the samples before and after 2‐phase EC sampled at different parts of the system were tentatively identified by using solid phase micro extraction (SPME) and gas chromatography hyphenated with mass spectrometry (GC‐MS). The results revealed different types and amounts of the odor active compounds in the samples after the 2‐phase EC treatment with the enhanced fruity, floral, sweet, green, minty, herbal and citrus smells. The electrochemical oxidation/reduction and esterification/hydrolysis were proposed as the possible reactions. The developed 2‐phase EC technique has a potential for application in the area of cost‐effective adjustment of essential oil and perfume quality.

On the specific limitations of titanium electrodes in the electrocoagulation process

The comparative electrocoagulation treatments of two representative samples, a colloidal dispersion and a soluble dye, have been investigated within the same conditions in the presence of titanium and aluminum plates. The results indicate that behaviors specific to titanium electrodes contribute to reduce significantly the effectiveness of the electrocoagulation process. Contrarily to aluminum, a sufficient release of coagulants is inhibited during titanium anode dissolution due to enhanced anodization and dense, close-packed, titanium-based precipitates are formed together with stable titania nanoparticles causing a persistent turbidity in the bulk that makes separation more difficult.

Continuous electrocoagulation treatment of Borneo tropical brackish peat water from palm oil plantation region for domestic consumption in rural coastal areas

Sarawak located on Borneo Island has vast availability of tropical brackish peat water sources, especially at palm oil plantation regions in rural coastal areas. However, this water source is currently underutilized as source for water treatment plant in the state. As such, this study aims to investigate the feasibility of continuous electrocoagulation treatment to treat Borneo tropical brackish peat water at varied initial salinity levels for domestic consumption in rural coastal areas. Correspondingly, the main objectives of this study are (i) to conduct an experimental study analysis to treat tropical brackish peat water at varied initial salinity levels and residence time, (ii) to compare the treated water quality to the Malaysian National Water Quality Standard (NWQS), and (iii) to conduct energy operating cost analysis. Subsequent, this study has found that the treated water could meet the recommended levels in NWQS with maximum reduction efficiency at 94.09% of colour, 89.91% of total suspended solids, 63.19% of pH, 78.93% of electrical conductivity, 92.71% of chemical oxygen demand, 80% of salinity, and 86.04% of turbidity with optimal residence time of 5 min. From the energy operating cost analysis conducted, the optimal energy consumption cost only Ringgit Malaysia (RM) 0.12 or United States Dollars (USD) 0.03 per cubic metre of brackish peat water treated. Overall, the study has demonstrated that continuous electrocoagulation treatment is feasible to simultaneously reduce natural organic matters and salinity from Borneo tropical brackish peat water in which compliance to the NWQS at reasonable cost.

The effect of electrocoagulation (EC) on total arsenic, arsenite (As3+) and arsenate (As5+) species removal from model groundwater investigating toxicity and sludge characteristic

This study showed that the model groundwater containing As3+ and As5+ species was successfully treated with electrocoagulation (EC) first time in the literature investigating toxicity reduction, inorganic arsenic species and detailed sludge characterization. The arsenic removal from model groundwater with 1000 µg/l total arsenic containing equal arsenite (As3+) and arsenate (As5+) concentration was examined by the EC treatment optimized with following parameters; current density (5.0, 7.5 and 10.0 mA/cm2) supporting sodium sulfate electrolyte amount (10, 20 and 30 mM Na2SO4) and initial water pH (3, 6 and 9). In EC treatment, the 99.87% arsenic removal was obtained with 10 mA/cm2, 10 mM Na2SO4 at pH 3 after 40 min supplying 1.44 μg/l effluent As concentration lower than the WHO limit for drinking water. Through transformation mechanisms of more toxic As3+ to less toxic and easily settled As5+ according to As speciation analysis, the toxicity of the model groundwater was successfully decreased in parallel with total arsenic, As3+ and As5+ removal during EC. The precipitated Al(OH)3 and Al2O3 coagulants were the main peaks in the FTIR-ATR spectrum as well as As(III)–O vibration observed between 717 and 721 cm−1 peaks and As(V)–O vibration dominated 899 and 972 cm−1 peaks were detected in the produced sludge after the EC. The SEM–EDS morphological analysis was demonstrated that the sludge was consisted of mostly amorphous structure aggregated size range of 200 μm–2 mm, relatively uniform cake including O, Al, As, Na, and S.

Electrocoagulation treatment of cork boiling wastewater

Electrocoagulation (EC) was studied as an alternative treatment for Cork Boiling Wastewater (CBW). EC was performed in a bench-scale reactor, using aluminum and stainless-steel electrodes and a sodium chloride solution was used to increase conductivity. Different values of current density, electric tension and electrolyte concentration were tested to assess treatment efficiency and operational costs. The tested procedures achieved removal efficiencies of 93.5%, 82.5%, 88.9% and 99.0% for chemical oxygen demand (COD), total carbon (TC), total nitrogen (TN) and total suspended solids (TSS), respectively, using an electric tension of 15 V. Some experiments after 20 min reached the maximum COD removal, showing that reduction of the operation time can be feasible to maximize cost-efficiency. The prediction of COD removal in a batch treatment based on initial NaCl concentration was investigated during a reactional period of 60 min, demonstrating that higher electrolyte concentrations promote COD removal. Langmuir, Jovanovic Monolayer and Multilayer models were applied and studied to predict the effect of current density and total aluminium mass on COD removal efficiency after 60 min of reaction. The Jovanovic Multilayer model predicted the operating performance for the removal of COD from CBW with higher accuracy when considering the current density. Operational costs for 60 min of electrocoagulation reactional periods have been determined in correlation with current density, in terms of cost per m3, €/COD removed, €/TN removed, €/TC removed, and €/TSS removed. Costs vary between 2.78 and 25.35 €/m3 with 27.6% and 93.8%, respectively. Electrode wear was higher than predicted, suggesting that about 14% of the mass loss should correspond to chemical dissolution. Results show that higher current density and electrolyte concentration reduces electrode wear time but increase overall pollutant removal.

Evaluation of operational parameters for the removal of turbidity and total coliform from wastewater using fabricated electrocoagulation treatment unit

The purpose of this study was to design and fabricate a prototype electrocoagulation wastewater treatment unit. The treatment system consist of wastewater storage tank, reactor tank with electrodes, treated water collection tank, filtration unit, filtered water storage tank, DC power supply. The study focuses on the effect of electrocoagulation treatment unit on treatment of wastewater containing physical and biological impurities using aluminium and iron electrodes. The aluminium electrodes used as anode and iron electrodes used as cathode. This study was based on treatment of synthetic wastewater containing turbidity and total coliform colonies. The unit was optimized at various operating conditions including pH, current density, and contact time. Impurities removal efficiency of designed Electrocoagulation (EC) unit was investigated at various conditions. Batch flow system was used for operation of reactor. From the experiments, the best turbidity removal efficiency was 94% at 6.5 pH, 18 mins and 3 A and for total coliform the removal efficiency was 98.95 % at 6.5 pH, 18mins and 3A. Results showed that aluminium and iron electrode are very effective electrode material for removal of physical and biological impurities cost effectively.

Electrocoagulation treatment of raw palm oil mill effluent: Optimization process using high current application

In the electrocoagulation wastewater treatment process, extremely polluted water treatment requires an effective technique, and using high current is one of those. This study aims to optimize electrocoagulation parameters such as operation time, electrodes gap and the initial pH by applying high current intensity to treat palm oil mill effluent (POME) via Box–Behnken design (BBD) method. Chemical oxygen demand (COD), biological oxygen demand (BOD), and suspended solids (SS) were used as the response variables in the quadratic polynomial model. Most of the selected models in the analysis of variance (ANOVA) have shown significant results. A high connection between the parameters and dependent variables was surprisingly discovered in this study which the obtained value of R2 for removal percentage of COD, BOD and SS were 0.9975, 0.9984 and 0.9979 respectively. Optimal removal was achieved at 19.07 A of current intensity (equivalent to 542 mA/cm2 of current density), 44.97 min of treatment time, 8.60 mm of inter-electrode distance and 4.37 of pH value, resulted in 97.21%, 99.26% and 99.00% of COD, BOD and SS removal respectively. This optimized scheme of operating parameters combination offers an alternate choice for enhancing the treatment efficiency of POME and also can be a benchmark for other researchers to treat highly polluted wastewater.

Solar-powered electrocoagulation treatment of wet flue gas desulfurization wastewater using dimensionally stable anode and induced electrode

Solar-powered electrocoagulation (EC) process is proven to be an alternative option for wet flue gas desulfurization (WFGD) wastewater treatment, due to simultaneous removal of multiple pollutants efficiently and reduce the operation costs significantly. Rapid and stable photoelectricity response is necessary for the removal efficiency of pollutants (eg. COD and turbudity), especially in low solar irradiation intensity. In this paper, dimensionally stable anode (DSA) and operation voltages in EC process driven by solar cells were investigated, for the purpose of the optimized removal of pollutants, including COD, turbidity, (free residual chlorine and chlorine dioxide). The results show that the removal efficiency of COD and turbidity can respectively reach 59.12% and 39.11% within 30 min of illumination time (the enhanced solar radiation = 915.8 W m-2), when Ti-based plates were adopted. The concentration of free residual chlorine and chlorine dioxide can reach 2.70 and 5.31 mg L-1, indicating that chlorine ions present in WFGD wastewater have been converted into active chlorine partly. Solar-powered EC equipped with Ti-based plates have a potential prospect in EC process for WFGD wastewater treatment.