Continuous Electrocoagulation Process Research Articles

The Investigation of Treatment of Pistachio Processing Industrial Wastewater by Electrochemical Methods in Terms of Chemical Oxygen Demand and Total Phenol Removal

<p>This work aims to investigate the efficiency of electrocoagulation (EC) of pistachio processing industrial wastewater (PPIW) using the continuous EC process. The tubular reactor made of stainless steel with an internal diameter of 60 mm was used as a cathode electrode. The effect of some parameters was examined on the removal of chemical oxygen demand (COD) and total phenols (TP) removal efficiency. The influences of the initial pH of wastewater (from 4 to 8), flow rate (from 25 to 125 mL/min), current density (from 7 to 21 mA/cm<sup>2</sup>), and supporting electrolyte type (NaCl, NaNO<sub>3</sub>, and Na<sub>2</sub>SO<sub>4</sub>), supporting electrolyte concentration (from 10 to 100 mg/L NaCl) on removal efficiency were investigated to determine the best experimental conditions. The examination of the physico-chemical parameters during the EC treatment showed that the best removal efficiency was obtained under conditions where the flow rate was 25 mL/min (20 min reaction time), the pH value was 5.2, and the current density was 21 mA/cm<sup>2</sup> has set. Under these experimental conditions, COD and TP removal efficiency were found to be 75% and 97%, respectively, while energy consumption was 18.5 kW h/m<sup>3</sup>. The study results show that the EC can be applied to PPIW pre-treatment.</p>

The Effect of Electric Voltage Variation and Flow Rate on Decreasing Remazol Red Rb 133 Dye Levels in a Continuous Electrocoagulation Process

The usage of synthetic dyes, such as Remazol Red RB 133, benefits the product by boosting its added value, but it also has a negative influence on the aquatic environment when waste water is disposed of directly. As a result, electrocoagulation technology is utilized to lower the levels of Remazol Red RB 133 dye, ensuring that it does not affect the environment. This study seeks to examine the influence of variations in electric voltage (10, 12, 14 volts) and flow rate (80, 100, and 120 mL/minute) on decreasing concentrations of the colorant RB-133 Remazol in the Continuous Electrocoagulation Process. A UV-Vis spectrophotometer will be used to see the dye concentration after the electrocoagulation process and will be analyzed using the adsorption kinetics model and the Langmuir and Freundlich adsorption isotherm models.

Parametric optimization and modeling of continuous electrocoagulation process for the removal of fluoride: Response surface methodology and machine learning approach

Parametric optimization and modeling of continuous electrocoagulation process for the removal of fluoride: Response surface methodology and machine learning approach

Treating hydraulic fracturing produced water by electrocoagulation

ABSTRACT Hydraulic fracturing oil- and gas-produced water is frequently highly impaired. While it is often deep well injected, there is a great deal of interest in treating and recovering this water for beneficial uses. However, multiple-unit operations are needed if these wastewaters are to be recovered. Electrocoagulation is considered a promising pretreatment technology. Herein, we have investigated the use of aluminum electrodes for electrocoagulation as a pretreatment operation. The effects of electrode arrangement, applied current, reaction time, pH and inter-electrode distance on the quality of the treated water have been investigated. The results obtained here indicate that electrocoagulation can obtain good removal of turbidity (95%), total suspended solids (TSS) (90%) and total organic carbon (TOC) (69%) by carefully choosing the reaction conditions. Sedimentation was used to separate the treated water from the sludge. The performance of the electrocoagulation process depends strongly on the quality of the feed water. The viability of a practical continuous electrocoagulation process will depend on the volume (footprint) of the reactor, which in turn will depend on operating conditions and the quality of the feed water.

Continuous electrocoagulation of Chlorella vulgaris in a novel channel-flow reactor: A pilot-scale harvesting study

The most frequently used method to harvest microalgae on an industrial scale is centrifugation, although this has very high energy costs. To reduce these costs, a continuous electrocoagulation process for harvesting Chlorella vulgaris was developed and tested using a pilot-scale 111 L working volume device consisting of an electrolyser with iron electrodes, aggregation channel and lamellar settler. The flow rate of the microalgal suspension through the device was 240 L/h. When using controlled cultivation and subsequent electrocoagulation, a high harvesting efficiency (above 85%), a low Fe contamination in the harvested biomass (<4 mg Fe/g dry biomass, a harvested biomass complied with legislative requirements for food) and significant energy savings were achieved. When comparing electrocoagulation and subsequent centrifugation with the use of centrifugation alone, energy savings were 80 % for a biomass harvesting concentration of 0.23 g/L. Electrocoagulation was thus proven to be a feasible pre-concentration method for harvesting microalgae.

Electrocoagulation in the dual application on the simultaneous removal of fluoride and nitrate anions through respective adsorption/reduction processes and modelling of continuous process

Electrocoagulation (EC) is known as an electrochemical process for the efficient removal of various pollutants including fluoride and nitrate anions. Continuous electrocoagulation (CEC) was applied to synthetic aqueous solutions containing mixtures of nitrate and fluoride anions both at initial concentrations of 0.1 g L−1 for simulation of effluents arising from the etching process in microelectronic industries. Several parameters such as electrode material, pH, current density, initial concentration as well as the presence of co-existing ions were studied. Without addition of an electrolyte, the optimizing conditions were found for aluminum electrodes at pH = 5.94, current density of 9.09 mA.cm−2 and distance between electrodes of 18 mm, leading to removal rates of 42.83% and 88.28% for nitrate and fluoride anions, respectively. The isolated electrogenerated solids were characterized by Energy Dispersion Spectroscopy (EDS) coupled to SEM, FT-IR, XRD, XPS, TGA and Raman spectroscopy. All the characterizations agree with the removals of nitrate and fluoride anions by reduction and adsorption, respectively. The anode and the cathode were involved, but the reduction and adsorption processes were independent of each other. The nitrate reduction was a cathodic reaction leading to hydroxide anions which were involved in the formation of electrogenerated adsorbents by reaction with the aluminum cations (or metal cations) arising from the anode oxidation. A modelling kinetic theory for a continuous electrocoagulation process was developed and applied to the treatment of artificial and real wastewaters. The treatment cost of the real wastewater was found at 2.3097 USD per m3.

Effect of electrode and electric current on peat water treatment with continuous electrocoagulation process

Peat water is surface water that inundates an area, formed from a pile of organic material for a long time. Peat water can skin irritation and metabolic disorders. The purpose of this study was to determine the application of the electrocoagulation method to neutralize pH and reduce levels of TSS and Fe in peat water and also to determine the effect of changes in electrode distancing and electric current on decreasing TSS and Fe levels and neutralizing the pH of peat water. The parameters tested include pH, TSS (Total Suspended Solid), and Fe content. The electrocoagulation process used electric current which flows in the direction through the electrodes. Electrocoagulation pipe was installed with electric cable that connected to the power supply with variation of current (1.0; 1.4; and 1. 8 A) and electrode distancing variations (0.5; 0.75; 1 in.). The results of this study show the optimum conditions obtained at 1.8 Ampere and 0.75-inch electrode distance with an increase in pH from 3.5 to 6.8, removing TSS from 128 to 36 mg / L, a decreasing Fe of 78.9% from 2.405 mg/L to 0.506 mg/L.

Modeling and optimization of a continuous electrocoagulation process using an artificial intelligence approach

Abstract An artificial neural network (ANN) with the topology 8-94-85-2 (input – hidden layer 1 - hidden layer 2 - output) was used to model the operation of the continuous electrocoagulation (CEC) process for the removal of fluoride from water. After the ANN training, the sum of the squared errors (MSE) and the determination coefficient (R2) of the testing set model predictions were 0.0088 and 0.999, respectively, showing a good generalization and the model's predictive capacity. The optimization of the process cost using the genetic algorithm (GA) showed that the optimal conditions are highly dependent on the feed concentration and the fluoride removal requirements. For 5 L of water containing 10 mg/L of fluoride, the optimal conditions to reduce the fluoride concentration below the permissible limit (1.5 mg/L) are 88.3 mA of current intensity, a flow rate of 73.6 mL/min, and the use of a series monopolar (SM) electrode configuration, corresponding to a fluoride removal of 85% and an operating cost of 0.05 €/L.

Application of Continuous Electrocoagulation Process for Distillery Wastewater Treatment

The present research deals with the treatment of distillery wastewater by continuous electrocoagulation (CEC) process using iron (Fe) as an electrode material. Effects of flow rates (L h−1) and residence time (τ) were studied on removal of various physicochemical parameters (TS, color, COD). COD removal efficiency of 80.10 and 83.1%; and color removal efficiency of 83.2 and 91.5%, respectively was achieved at flow rates of 1.0 and 0.5 dm3 h−1. After 3 h residence time and flow rate of 1 dm3 h−1, TS concentration of wastewater slurry was also decreased by 69%. SEC was decreased from 16.3 to 14.3 kW h per kg COD removed with change in τ from 4 to 1 h. Dissolution and consumption of electrodes were also investigated with a change in flow rates.

Impact of turbidity, hydraulic retention time, and polarity reversal upon iron electrode based electrocoagulation pre-treatment of coal seam gas associated water

The applicability of iron (steel) electrodes in a continuous electrocoagulation (EC) process to treat coal seam gas (CSG) associated water comprising of a high level of turbidity (421 NTU) was studied. Key objectives were to understand the influence of turbidity upon water quality when hydraulic retention time (HRT) and polarity reversal time (PRT) were tested using a bench top EC unit. Extension of HRT promoted removal of dissolved alkaline earth ions (Ca 23 to 45 %; Mg 60 to 97 %; Ba 25 to 54 %; Sr 10 to 19 %), silicates (90 to 93 %) and boron (8 to 12.7 %); whereas turbidity was optimally reduced at a HRT value of 30 s (98.5 %). Turbidity particularly promoted magnesium removal which may be due to destabilization of the clay suspension. However, clay particles also inhibited the rate of floc settling. The greater performance of EC with increasing HRT was achieved at a cost of increased consumption of electrodes and electricity. PRT reduced power consumption with an optimal value being at least 5 min (4.12 to 3.88 kWh/kL for PRT values of 1 and 5 min, respectively). Removal rates of dissolved species were not greatly influenced by PRT. Surface passivation at low PRT values produced higher amounts of hydrogen gas which caused the flocs to float. In summary, HRT, PRT, turbidity level and solution composition were critical parameters in relation to the potential use of EC in the CSG industry.

Pengolahan Limbah Cair Industri Minyak Sawit Menggunakan Reaktor Listrik Plat Kolom Secara Kontinu serta dengan Penambahan PAC

Palm oil industrial waste contains various dissolved compounds in the form of short fibers, hemicellulose, and their derivatives, proteins, free organic acids, a mixture of minerals and organic pigments such as anthocyanins, carotenes, polyphenols, lignins and tannins. Organic compounds in this waste will cause problems such as an increase in TSS, COD values which can pollute the environment. The electrocoagulation method has the potential to reduce TSS, TDS, COD content and neutralize pH. The purpose of this study was to determine the effect and optimum conditions of the electrocoagulation process with variations in flow rate, voltage, spacing between plates and the addition of poly aluminum chloride (PAC) coagulants to decrease TSS, COD and pH parameters so that they meet the quality standards of waste in Permen LH. No. 5/2014. The method used is a continuous electrocoagulation process using an aluminum catalyst and the addition of PAC. The variables used in this study were the stress variable (24; 26; 28 V) and the variable flow rate velocity (0.3; 1,2; 2.5 L / min) and the variation of the spacing between the plates (2, 3, 4 cm). The results of this study found that the optimum conditions were obtained at a voltage of 28 volts and a flow rate of 0.3, and a distance between the plates of 2 cm and the addition of 400 ppm PAC with a percentage of TSS removal of 92.093% from 2150 mg / L to 170 mg / L, and a decrease in COD of 85.343% from 1310 mg / L to 192 mg / L. The results obtained show that it is in accordance with the standards of the Ministry of Environment and Forestry Regulation No.5 of 2014.

Optimization and mechanisms analysis of indigo dye removal using continuous electrocoagulation

Abstract Electrocoagulation (EC) is among the most effective techniques that remove color and decontaminate effluent. Coagulants are delivered in situ by anode corrosion. In this research, indigo dye removal using iron electrodes in continuous electrocoagulation process and the responsible species for decolorization were investigated. The Response Surface Methodology (RSM) was used to optimize the process parameters. The finding in this study shows that at fixed conductivity at 15,000 μS·cm−1, the neutral conditions (pH from 6 to 8), the low absorbance, the low flow rate and the high voltage level enhance the color removal efficiency. The high R2 value of 97.8% and ANOVA analyses show a good correlation between the experimental and predicted results. Under the optimum conditions, which are pH of 7.5, solution concentration of 60 mg·L−1, inlet flow rate of 2 L·min−1 and voltage of 47 V, the predicted decolorization of 94.083% was achieved at 93.972% with a total cost of 0.0927 USD·m−3 of treated effluent. At the optimum pH (7.5), the zeta potential value (− 4 mV) of the effluent during EC match with the one of iron III hydroxide. The dye removal is ensured thanks to physical adsorption and flocculation. The results exposed in this work prove that the continuous electrocoagulation process could be successfully used for indigo dye removal at industrial scale.

Optimization of NaCl concentration and electrocoagulation processing time to reduce the level of chromium heavy metal solutions

The process of reduction of Cr from the wastewater of the metal coating industry can be carried out by electrocoagulation process. The purpose of this research was to reduce the levels of Cr in solutions, containing Cr as a preliminary study for the determination of NaCl levels added as electrolyte media and the determination of optimal electrocoagulation processing time. This research was laboratory experiments with a continuous electrocoagulation process using iron electrodes, with variations in addition of NaCl and processing time. Determination of Cr in solutions was carried out before and after electrocoagulation using an Atomic Absorption Spectrophotometer (AAS). Two-way ANOVA was used to analyze the result and showed that the significance value of the variation of NaCl concentration and processing time are decrease concentration of heavy metal Cr in solutions was 0.001 (p <0.05). These results indicate that there is a significant difference in the concentration of Cr which is significant in terms of variations in NaCl concentration and variations in electrocoagulation processing time. Based on these results, it can be concluded that the continuous system electrocoagulation process with the addition of 1.20 % w/v a time of 60 minutes gave the most optimum reduction of Cr.

Continuous electrocoagulation process for pretreatment of high organic load moquette industry wastewater containing polyvinyl acetate: a pilot study

ABSTRACTMoquette-manufacturing industry is one of the textile industries that produces high organic load wastewaters containing polymeric adhesives, especially polyvinyl acetate (PVAc). The generated wastewater cannot be easily treated by commonly used traditional methods. Therefore, in this study, continuous electrocoagulation process (CECP) was applied for pre-treatment of real wastewater from moquette-manufacturing industry. For this purpose, the influences of different operational parameters, such as electrode distance, current density (CD), hydraulic retention time, and electrode type were investigated on the process performance at pilot scale. Under optimal conditions (neutral solution pH, optimum CD of 21 mA/cm2, Charge passed of 0.53 C/cm2 and hydraulic retention time of 25 min), the removal efficiencies of chemical oxygen demand (COD), total suspended solid (TSS), PVAc, total dissolved solid (TDS) and electrical conductivity (EC) using the CECP with Fe–Fe electrode (as the best electrode) were 90.4%, 91.3%, 93.9%, 59.7% and 72.6%, respectively. The results showed the process efficiency increased with decreasing electrode distance, and increasing of CD and retention time. The consumption rate of electrical energy increased with increasing electrode distance, CD and reaction time. Under the optimal conditions, the consumption rates of electrical energy for iron and aluminium anodes were 2.4 and 6.1 kwh/m3, respectively. Also, the electrode consumption for removal of 1 kg of COD using iron and aluminium anodes at the optimum CD was 4.2 and 3.2 Kg/kg CODremoved, respectively. Therefore, it can be concluded that CECP can be used as an effective and economical method for pre-treatment of moquette industry wastewater compared with the traditional methods.

A novel single continuous electrocoagulation process for treatment of licorice processing wastewater: Optimization of operating factors using RSM

The potential application of a novel continuous electrocoagulation (EC) reactor for simultaneous removal of color, chemical oxygen demand (COD), turbidity, and alkalinity from a real licorice processing wastewater was investigated. The individual and interactive effects of four key independent variables (electrolysis time, current density, NaCl concentration, and mixing intensity) was evaluated. The results suggested that color and COD removal enhances with increasing electrolysis time, current density, and mixing intensity and remains practically constant by adding higher concentrations of NaCl. The application of continuous EC process under optimal conditions, such as: electrolysis time (81.8min), current density (350 A/m2), NaCl concentration (300mg/L), mixing intensity (45rpm) allows to achieve these promised removal efficiencies: 90.1 % color, 89.4 % COD, 82 % turbidity, and 73.3 % alkalinity.

Performance of Continuous Electrocoagulation Process for Turbidity Removal from Sand Filter Backwash Water

The presence of particles such as algae, clay, organic materials and water-soluble substances often create turbidity or color in water. In recent years, electrocoagulation process has attracted an extensive attention due to its advantages. Since sand filters are widely used in water treatment industry and their corresponding backwash water is large in volume, turbidity removal will save water consumption and its recycling. In this study, real samples of backwash water from sand filters of a water treatment plant in Alborz province were collected. The turbidity removal was further evaluated under operating conditions of 6, 12, 18 and 30 V as the exerted voltages, electrode distances of 1 and 1.5 cm, different initial turbidities (391 NTU as sample 1 and 175 NTU as sample 2), iron and steel as the sacrificial electrodes in a continuous electrocoagulation reactor. According to the results, the optimum conditions without considering the process economy was found to be 30 V, the iron electrode and electrode distance of 1 cm and samples 1 and 2 had an effective turbidity removal efficiency of 98.4 and 91.6%, respectively.

Removal of Cypermethrin and Chemical Oxygen Demand from Livestock Wastewater by Electrocoagulation

AbstractThe direct discharge of wastewater from livestock into freshwater and surface runoff originating from processing areas threaten aquatic ecosystems and the quality of drinking water taken from streams. The present work studied the removal of chemical oxygen demand (COD) and cypermethrin (Cyp) from livestock wastewater generated after cattle baths by a continuous electrocoagulation (EC) process. The effect of pH, retention time, and voltage on COD and Cyp removal was examined. Under the optimal operating conditions, EC effectively removed COD (93 %) and cypermethrin (96 %). Thus, continuous EC was successfully applied to treat livestock wastewater.

Treatment and operating cost analysis of metalworking wastewaters by a continuous electrocoagulation reactor

Environmental pollution is a persistent global challenge of industrialisation. In this study, metalworking wastewater (MWW) containing COD of 17,312 mg/L, TOC of 3155 mg/L and turbidity of 15,350 NTU was treated by continuous electrocoagulation process (CEP). At current densities between 30–90 A/m2, and reactor retention time (τ) of 35 min (Q = 0.10 L/min), removal efficiencies for COD, TOC and turbidity were 68.0–87.0%, 55.2–77.7% and 85.0–99.6%, respectively for Al electrode. Whereas removals for COD, TOC and turbidity with Fe electrode were 75.1–94.8%, 72.2–89.5% and 88.1–99.9%, respectively. Futheremore, varying flow rate from 0.010-0.20 L/min (τ of 350-17.5 min) at 90 A/m2, resulted into COD, TOC and turbidity removals of 92.6–71.3%, 83.3–64.9% and 99.9–88.9% for Al electrode and 97.8–78.6%, 94.9–69.9% and 99.9–94.7%, respectively for Fe electrode. Analysis of operating costs (OC) encompassing consumptions of energy, electrodes, chemicals and landfill disposal of generated sludge for 30−90 A/m2 current density showed a variation from 1.37 to 4.74 $/m3 and 1.03–3.80 $/m3 for Al and Fe electrodes, respectively. Similarly, the OC for 0.010-0.20 L/min flow rates were 4.34–4.88 $/m3 (3.34–1.11 $/kg COD) and 3.58–3.85 $/m3 (7.73-1.41 $/kg COD) for Al and Fe electrodes, respectively. At optimum conditions (EC time = 40 min, τ = 70 min, and 90 A/m2), COD, TOC and turbidity removals from MWW by CEP were 94.3%, 90.1% and 99.3%, respectively with Fe electrodes. At these optimums, the OC was 3.09 US $/m3 (2.63 US $/kg removed COD). The results showed that CEP was an effective alternative process for treatment of the MWW.

Removal of Fluoride from Water by a Continuous Electrocoagulation Process

The present work proposes a continuous electrocoagulation experimental setup for the removal of fluoride from water using aluminum electrodes. The experimental results showed that the proposed proc...

Simultaneous removal of arsenic and fluoride from synthetic solution through continuous electrocoagulation: Operating cost and sludge utilization

The present study deals with simultaneous removal of arsenic and fluoride by continuous electrocoagulation (EC) process using aluminum electrodes. Effects of flow rates: 0.48–1.40 L/h and residence time (τ): 60–173 min have been studied on the removal of arsenic and fluoride. The percentage removals of arsenic and fluoride are found greater than 98.83% and 87.5% respectively. The concentrations of arsenic and fluoride in treated water are also found below the permissible limits as per World Health Organization (WHO) guidelines (As: 10 μg/ L, F: 1.5 mg/ L). The optimum cost of continuous EC is found to be 0.358 USD/m3 at a flow rate of 0.88 L/h with 95 min residence time. Produced sludge has been analyzed by FESEM, XRD and FTIR. Sludge characterization confirms that arsenic and fluoride are linked with aluminum hydroxide complexes. Solidification technique has been used for the management of the produced sludge by its immobilization in the form of clay brick. Leaching test results show that leaching of arsenic and fluoride from the brick is much below the permissible limits assigned according to the US Environmental Protection Agency (USEPA) norms. The brick quality parameters are found above the respective permissible limits as per Indian standard indicating it suitability for use in construction purposes.