Efficiency Of Electrocoagulation Research Articles

Investigating the efficiency of electrocoagulation using similar/dissimilar electrodes for the detoxification of Coralene Rubine dye: a cost effective approach.

Efficient treatment of textile dyeing wastewater can be achieved through electrocoagulation (EC) with minimal sludge production; however, the selection of the appropriate electrode is essential in lowering overall costs. Also, the reuse of the treated aqueous azo dye solution from this process has not been explored in detail. With these objectives, this study aims to treat synthetic azo dye solutions and achieve high colour removal efficiency (CRE%) using similar (Ti-Ti) and dissimilar (Ti-Cu) metal electrodes through EC with an attempt to reduce the cost. The aqueous Coralene Rubine GFL azo dye was used to examine the efficiency and cost of the EC process. X-Ray Photoelectron Spectroscopy was used to study the EC mechanism, while High Performance Liquid Chromatography was used to analyse the degradation of the dye and the formation of intermediate compounds. The concentration of metal ions in the treated dye solution was quantified using Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES), with Ti-Ti treated solution having 14.20mg/L concentration of Ti and Ti-Cu treated solution having 0.078mg/L of Ti and 0.001mg/L of Cu, respectively. Colour removal efficiency of 99.49% was obtained for both electrode sets, with a lower operating time and voltage for dissimilar metal combination. Ecotoxicity studies showed negligible toxicity of Ti-Cu treated dye samples compared to untreated solutions. Survival rate, protein estimation, and catalase activity was used to validate the treatment method's efficacy. The study found that the dissimilar electrode material exhibited reduced toxicity due to the presence of heavy metals below the permissible limit.

Evaluation of parameters in the removal of azo Red 40 dye using electrocoagulation

The objective of the present investigation was to evaluate the parameters that affect the efficiency of electrocoagulation in a batch system to remove the azo-benzoic dye Red 40 present in synthetic wastewater by determining the effect of the operational parameters of voltage and treatment time. A 12×6 cm iron electrode holder was constructed with PVC pipes and screws separated by 2 cm, and a 1 L beaker was used as the electrocoagulation cell. Synthetic wastewater samples of red 40 were characterized, where UV–VIS was used to measure absorbance before and after being treated in the electrocoagulation cell. The effects of voltages (10, 15, and 20 V) and treatment times up to 60 min were evaluated. As a result, a higher removal of 93.85 % was obtained at 60 min when a voltage of 10 V was used with a lower change in temperature and energy consumption of only 14.08 kJ. The increase in conductivity and pH by values greater than 1600 µs/cm and 11, respectively, indicate the presence of diluted iron at the end of treatment; therefore, if complemented with other treatment methods such as filtration to remove excess iron produced, can be used in treatment plants and reduce their environmental impact, for this research the FTIR analysis showed that the sludge has a dye composition with hydroxides of metals along with a slight trace of dye degradation.

A comparison of the efficiency of electrocoagulation and alum NPs for tannic acid removal from aqueous solutions

A comparison of the efficiency of electrocoagulation and alum NPs for tannic acid removal from aqueous solutions

Determination of the effectiveness of the electrocoagulation process in the treatment of leachate from the controlled landfill site in Francisco de Orellana canton

The inadequate management of leachate produced in landfill sites, sanitary dumps, or its incomplete treatment generates significant environmental and public health impacts. These conditions are expected in developing countries and are a major concern, especially in sensitive areas like the Amazon. This study investigated the efficiency of electrocoagulation for removing BOD5, COD, TSS, turbidity, and color using a laboratory-scale reactor. Samples of raw leachate from the controlled landfill site in Francisco de Orellana canton, located in the Ecuadorian Amazon, were used. First, the initial conditions of the leachate were determined through a physicochemical characterization, where a reduced presence of heavy metals and high biodegradability were identified, suggesting that it is old leachate. In turn, a reactor with 5 electrodes was installed, where aluminum was used as a cathode and iron as an anode. Finally, electrocoagulation was employed with various operational combinations, where a run using 2.5 V and 20 minutes showed the highest removal efficiency on average, with reductions of 85.23% of BOD5, 98.20% of COD, 11.30% of TSS, 96.52% of turbidity, and 90.73% of color. Keywords: Electrocoagulation; Leachate; Leachate treatment.

Determination of the effectiveness of the electrocoagulation process in the treatment of leachate from the controlled landfill site in Francisco de Orellana canton

The inadequate management of leachate produced in landfill sites, sanitary dumps, or its incomplete treatment generates significant environmental and public health impacts. These conditions are expected in developing countries and are a major concern, especially in sensitive areas like the Amazon. This study used a laboratory-scale reactor to investigate the efficiency of electrocoagulation for removing BOD5, COD, TSS, turbidity, and color. Samples of raw leachate from the controlled landfill site in Francisco de Orellana canton, located in the Ecuadorian Amazon, were used. First, the initial conditions of the leachate were determined through a physicochemical characterization, where a reduced presence of heavy metals and high biodegradability were identified, suggesting that it is old leachate. In turn, a reactor with 5 electrodes was installed, where aluminum was used as a cathode and iron as an anode. Finally, electrocoagulation was employed with various operational combinations, where a run using 2.5 V and 20 minutes showed the highest removal efficiency on average, with reductions of 85.23% of BOD5, 98.20% of COD, 11.30% of TSS, 96.52% of turbidity, and 90.73% of color. Keywords: Electrocoagulation; Leachate; Leachate treatment.

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>

Faradaic efficiency and anodic electrochemical behavior of Fe electrocoagulation: The role of co-existing ions and ultrasonic assistance

Anodic passivation is a key factor affecting the Faradaic efficiency of Fe electrocoagulation. In practice the electrolyte nature of water matrix played a critical role in governing the Faradaic efficiency. In this study the effect of co-existing ions and ultrasonic field on the Faradaic efficiency and the electrochemical behavior of iron anodes was investigated. The results showed that in Cl− and SO42− solution Fe anode exhibited a typical characteristic of dissolution with a high Faradaic efficiency (>90 %), but severe passivation appeared in NO3− solution with a low Faradaic efficiency (4 %). However, adding Cl− can impair the passivation effect of NO3−. As the Cl−: NO3− ratio increased to 1:10, the Faradaic efficiency significantly increased to 90.65 %. Potentiodynamic polarization and electrochemical impedance spectroscopy analysis showed that the thickness of the passive film decreased and the corrosion rate increased, and thus promoting the anodic dissolution. In addition, ultrasonic field was introduced to assist electrocoagulation. In 50 mM NaNO3 + 2.5 mM NaCl solution, the Faradaic efficiency was only 12 % without ultrasonic assistance, but it increased to 60.9 % when the ultrasonic power was 180 W. Therefore, ultrasonic assistance was beneficial to reduce the anodic passivation and increase the Faradaic efficiency.

Efficiency and safety of electrocoagulation as a means of local hemostasis of the staple line in bariatric surgery

Efficiency and safety of electrocoagulation as a means of local hemostasis of the staple line in bariatric surgery

The Efficiency of κ-Carrageenan-Chitosan-PVA-MWCNTs Membranes in Removing Methylene Blue, Rhodamine B, Bromocresol Purple, and Murexid from Water

The electrocoagulation method has been proven to be highly effective in removing metal ions from water, with a removal efficiency of over 97%. However, in terms of removing organic pollutants such as synthetic dyes, the efficiency of electrocoagulation is still relatively low. A hybrid approach combining electrocoagulation with membrane filtration has been proposed to enhance the removal of organic contaminants. Eco-friendly membranes made from renewable natural polymers like carrageenan and chitosan, reinforced with synthetic polymers such as polyvinyl alcohol and carbon nanotubes, have shown to be promising for this application. In this study, membranes with varying chitosan/carrageenan ratios of 0.2, 0.33, 0.5, and 0.71 (g/g) were used to remove synthetic dyes, including methylene blue, rhodamine B, bromocresol purple, and murexid, at a concentration of 200 ppm from 8.5 ml of water. From the SEM images, the four membranes have almost the same surface and cross-section morphology. The results showed that the membrane with a chitosan/carrageenan ratio of 0.71 exhibited the highest removal efficiency for all synthetic dyes. The parameter affecting the membrane’s removal efficiency is the interaction between the membrane and synthetic dyes. Murexid, an anionic dye, achieved a 100% removal efficiency, surpassing cationic dyes such as rhodamine B and methylene blue. Besides interactions, the dye’s molecular size determines the removal’s efficiency. The molecular size of rhodamine B is larger than that of methylene blue, and the removal efficiency of rhodamine B (98.4%) is greater than methylene blue (91%). Bromocresol purple is almost the same size as rhodamine B but not ionic because it has the lowest removal efficiency of 34.55%.

Efficiency of electrocoagulation for simultaneous treatment of As and Mn in neutral mine water

Despite the efficiency and ease of implementation of electrocoagulation (ECG), its industrial application for the treatment of contaminated mine water is limited due to high energy and electrode consumption. The main objective of the present study was to identify the most performant ECG conditions using Fe–electrodes for the simultaneous removal of As(III) and Mn(II) from synthetic and surrogate neutral mine water, while limiting energy and electrode consumption. Treatability tests were performed on i) single synthetic effluents containing only 3.5mg/L As (SAs) or 4.5mg/L Mn (SMn), ii)binary synthetic effluents containing both As and Mn (SAs+Mn), and iii) surrogate mine water (Elow and Ehigh). The effect of current density (CD), ionic strength, and retention time were first evaluated for the treatment of SAs, SMn, and SAs+Mn. Then, the most performant conditions were used to treat Elow and Ehigh. The toxicity to Daphnia magna of Elow and Ehigh was evaluated before and after ECG treatment. The results showed that the increase of CD from 0.25 to 10 mA/cm2 greatly improved the removal of Mn and to a lesser extent of As, as well as energy and electrode consumption. Despite a negligible effect on the removal efficiency of As and Mn, the ionic strength (from 0.25 to 2.5mS/cm) and inter-electrode distance (from 10 to 50 mm) strongly affected the energy consumption. Results showed that ECG efficiently removed As (>97 %) from SAs at low CD (0.5 mA/cm2), while Mn required a 3.3-fold higher CD to achieve satisfactory removal (>60 %) from SMn. For the treatment of SAs+Mn, As removal was more efficient and faster than Mn removal (99 vs. 60 % and 20 vs. 60 min, respectively) at a CD of 2.0 mA/cm2. Moreover, the simultaneous removal of As and Mn at 2.0 mA/cm2 produced a volume of sludge 3.3 times greater than at 0.5 mA/cm2. Lastly, high As (99 %) and variable Mn (40–57 %) removal efficiencies were obtained after Elow and Ehigh treatment, with potential positive effect of the presence of Ca2+ and Cl- on the removal of As, while SO42- may have negatively affected the removal of Mn. After ECG treatment, no addition of toxicity to D. magna was observed for Elow and Ehigh. The outcomes of this study may provide promising insights for the application of ECG for simultaneous removal of metal(loid)s from contaminated mine water.

Treatment and optimization of high-strength egg-wash wastewater effluent using electrocoagulation and electrooxidation methods

Egg-washing wastewater contains a high concentration of nutrition and organic matter since eggs are broken during the washing and cleaning processes. Moreover, the wastewater contains small amounts of detergents or sanitizing agents. These contaminants may pose environmental challenges when they are not properly managed or treated. The study scrutinizes the efficiency of electrocoagulation (EO) and electrooxidation (EO) approaches for egg-wash wastewater treatment. The response surface methodology was employed to optimize the operational parameters. The removal efficiencies of soluble chemical oxygen demand (sCOD 90%), ammonia (NH3–N 91%), nitrate (NO3−-N 97%), nitrite (NO2−-N 89.3%), total dissolved nitrogen (TDN 91%), and phosphate (90%) were measured under various treatment conditions. The optimum treatment conditions achieved in the combined EC + EO process were pH 6.0, current density 20 mA cm−2, and electrolysis time of 60 min, respectively. Degradation kinetics of the egg-wash pollutants showed a significant reduction in half-life (t1/2) with EO (after EC-Aluminum) at 15 min, 12 min, 17 min, and 15 min for sCOD, NO2−-N. NO3−-N, and TDN, respectively. Whereas the half-life of NH3–N (18 min) and phosphate (17 min) reduced significantly with the EO (after EC-iron). Al and Fe electrodes coupled with boron-doped diamond were found efficient for pollutant removal.Environmental implication.Egg-wash wastewater has a high protein content and contains nutrients that are essential for living organisms. While these compounds can be valuable for agricultural use by increasing soil phosphate concentration, they can also become an issue if the excess nutrients are not properly managed. The soil has a threshold limit for holding phosphate, and any excess amount may be transported through surface runoff or contaminate groundwater through leachate, potentially affecting aquatic ecosystems and water quality. This study explores the efficiency of electrocoagulation and electrooxidation methods in treating egg-wash wastewater. These methods aim to remove pollutants and reduce their environmental impact.

Mechanistic Insight into Electrode Processes by Operando Visualization of Interfacial pH Using Fluorescent Nanosensors.

Operando visualization of interfacial pH is crucial, yet challenging in electrochemical processes. Herein, we report the fabrication and utilization of ratiometric, fluorescent pH-sensitive nanosensors for operando quantification of fast-dynamic, interfacial pH changes in electrochemical processes and environments where unprotected fluorescent dyes would be degraded. Spatio-temporal pH changes were detected using an electrochemically coupled laser scanning confocal microscope (EC-LSCM) during the electrocoagulation treatment of model and field samples of oil-sands-produced water. Operando visualization of interfacial pH provided new insights into the electrode processes, including ion speciation, electrode fouling, and Faradaic efficiency. We provide compelling evidence that formed metal complexes precipitate at the edge of the pH boundary layer and that there is a strong coupling between the thickness of the interfacial pH layer and the electrode fouling. Furthermore, these findings provide a powerful pathway for optimizing the operating conditions, minimizing electrode passivation, and enhancing the efficiency of electrochemical processes, e.g., electrocoagulation, flow batteries, capacitive deionization, and electrolyzes.

Phosphonate removal from membrane concentrate by electro-coagulation

In this study, the efficiency of electrocoagulation (EC) with iron electrodes was applied to remove two phosphonates, 1-hydroxyethylidene-1, 1-diphosphonic acid (HEDP) and nitrilotris(methylene) triphosphonic acid (NTMP) from concentrates. This work provides a detailed description of the experimental procedure and results on phosphonate removal and recovery from different electrolytes, including synthetic and real reverse osmosis (RO) membrane concentrates. This research showed high selectivity of EC, removing 100% and 80% of the NTMP and the HEDP respectively, confirming no competition with sulfates, nitrates, or silica. When experimenting with other electrolytes, calcium showed to be critical in enhancing the flocculation process, while calcium carbonate precipitation contributed to capturing the phosphonates from the concentrate. The produced iron oxide (sludge) was confirmed as goethite and akaganéite, and finally transformed into hematite, indicating the oxidation from Fe2+ to Fe3+ during the EC process. After the iron precipitate collection, an alkaline wash of the sludge was enough to recover 100% of the initial phosphorus from the NTMP phosphonate. However, further research is needed to optimize the recovery procedure and to improve the results with the HEDP. 70 and 140 A·m−2 current densities were optimal to bring HEDP and NTMP concentrations down to 32 μM (1 mg·L−1) in only 30 and 10 min respectively. In these conditions, the operational costs, 1.10 and 0.03 €·m−3 of treated concentrate, were estimated for HEDP and NTMP respectively. Even when EC has been widely studied for phosphate removal, this technique has been barely applied to treat concentrates containing phosphonate-based antiscalants. EC opens new possibilities for phosphonates and phosphorus to be removed and recovered respectively from membrane and other concentrates.

Optimization of effluent treatment from healthcare waste incineration by electrocoagulation with iron electrodes

This study evaluated the efficiency of electrocoagulation in removing chemical oxygen demand (COD), turbidity, and apparent color from the incineration effluent generated in a gas cleaning system (GCS). Modeling and optimization of the variables electric current (I), hydraulic retention time (HRT), and electrode distance (ED) were also performed in a batch reactor using iron electrodes. A 23 rotatable central composite design CCRD was used, with a total of 19 trials, with electric currents ranging from 1A and 5A, a retention time of the effluent in the reactor from 15 to 40 minutes, and electrode distance of 1 and 3 centimeters. An algorithm with the desirability function was created to optimize simultaneously the parameters studied. The treatment of GCS by electrocoagulation was satisfactory in removing turbidity, apparent color, and COD, with maximum removal efficiencies above 70% for all parameters, using HRT of 27.5 minutes, ED of 2 centimeters, and electric current of 1 A. The statistical analysis showed a good fit of the model, with a coefficient of determination of R2 > 0.9. The optimum operating condition was observed at 1A electric current, 27 minutes HRT, and 2 centimeters of electrode distance, with removals of 82.07, 86.86, and 70.82% of COD, turbidity, and apparent color, respectively. The simulated trials showed that lower electrolysis times can be used without impairing the treatment efficiency. Therefore, electrocoagulation may be a potential tool in the treatment of GCS.
 Keywords: coagulation, electrolysis, gas scrubber, incineration.

Removal and toxic forecast of microplastics treated by electrocoagulation: Influence of dissolved organic matter

In recent years, the break of COVID-19 makes the large use of disposable products, which causes the removal of microplastics become an imperative problem. Electrocoagulation is one of the effective removal technologies, but there is hardly research concentrating on the effect of substrate in the actual water on the microplastics removal with electrocoagulation. As an important role of water bodies, dissolved organic matter (DOM) has a vital and inevitable effect on the efficiency of electrocoagulation. In this study, the effect of DOM in tailwater on microplastics during electrocoagulation is elucidated by comparing the electrocoagulation treatment results between simulated wastewater and tailwater, using parallel factor analysis (PARAFAC), Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectrometer (FTIR) and zeta potential analyzer. Three kinds of microplastic particles (i.e. polypropylene, polyethylene, and polymethyl methacrylate) were added into each of the two kinds of wastewaters to form six electrocoagulation systems. Results show that DOM in tailwater promotes the production of flocs and free radicals during electrocoagulation process. Fe2+ and Fe3+ are adsorbed on the surface of DOM molecules and combined with •OH form flocs. Although DOM accelerates the production of free radicals and thus promotes the aging of microplastics, flocs with DOM as crystal nucleus can prevent toxic substances and small-sized microplastics from leaching into water again. Therefore, electrocoagulation is preferred to removal microplastics in water with high concentration of DOM. This study provides a significant reference for microplastics removal by electrocoagulation in actual water, and promote the practical application of electrocoagulation for microplastics removal in water treatment.

Removal of Tannic acid and COD from synthetic Tannery wastewater

Tanning industries generate tannery wastewater having high amounts of tannic acid and high COD. Tannery wastewater is difficult to treat as it is having low biodegradability. Tannic acids or tannins are recalcitrant molecules that are toxic to a wide range of microorganisms. In this study, synthetic tannery wastewater treatment was performed by Electrocoagulation (EC) process. To extract the polyphenolic components of tannins, aluminum was employed as an anode electrode and stainless-steel as cathode electrode. Analysis of removal efficiencies was done by determining tannic acid concentration and COD. The effects of functional parameters such as current density, pH, and initial concentration of tannic acid were examined on the efficiency of electrocoagulation. At a current density of 30 A/m2 with an initial concentration of tannic acid of 1,000 mg/L, 94% of tannic acid removal and 94.92% of COD removal were observed. While tannic acid removal was fast, at 60 min, COD removal took a long duration of 120 min. The removal efficiency was observed for three various pH;4.11 (initial pH of the sample), 6, and 8. The maximal COD elimination was found to be accomplished at pH 4.11, which was the sample’s natural pH, whereas tannic acid removal was better at pH 6 and 8. Experiments with a varying initial concentration of tannic acid at 500 mgl−1, 800 mgl−1, and 1000 mgl−1 showed that as concentration was increased, the removal was difficult. The present study found the EC process effective in reducing COD and tannic acid concentration in synthetic tannery wastewater.

Electrocoagulation using scrap materials for removal of dye with different connection modes and electrode combinations

This study analyses the efficiency of electrocoagulation (EC) process by utilizing discarded metal scrap of Iron (Fe) and Aluminium (Al) as electrodes for decolourization of azo dye, Acid Yellow 36 (AY36). Different modes of connection such as mono polar parallel (M-P), mono polar series (M-S) and bi polar series (B-S) were investigated for the performance of percent colour removal and Electrical Energy Consumption (ENC). Within these connections, different electrode arrangements, such as Iron-Aluminium-Iron-Aluminium, Aluminium-Iron-Aluminium-Iron, Iron-Iron-Iron-Iron and Aluminium-Aluminium-Aluminium-Aluminium were analyzed for the dye removal efficiency. The parameters varied during the experimental runs were current density (CD) and pH. M–S showed maximum colour removal of 99.2% with system of mixed electrode Fe–Al–Fe–Al at CD 10 A/m2 and ENC 0.322 Kwh/Kg dye removed. Whereas M-P showed 98.4% colour removal with hybrid system Fe–Al–Fe–Al at CD of 20 A/m2 with ENC 0.209 Kwh/Kg dye removed. B-S showed 99.1% colour removal with mixed electrode system Al-Fe-Al-Fe at CD of 20 A/m2 and ENC 0.86 Kwh/Kg dye removed. Overall, M-S mode gave the maximum colour removal, while M-P gave minimum ENC. The study proved useful in terms of lowering the cost of electrocoagulation by using scrap metal as electrodes and choosing the right electrode combination and connection mechanism.

Development of arsenic removal unit with electrocoagulation and activated alumina sorption: Field trial at rural West Bengal, India

In the present study, electrocoagulation (EC) with iron electrodes along with adsorption by activated alumina has been evaluated as a treatment process for arsenic removal from groundwater. Batch scale experiments were performed with iron electrodes to assess the removal efficiency of electrocoagulation. The effects of inter-electrode distance and electro-charge loading (ECL) were evaluated on arsenic removal. EC was able to decrease the arsenic concentration in the aqueous phase below 10 ppb at ECL of 60 coulomb/L with 1 cm inter-electrode distance. The optimal condition was obtained by Response Surface Methodology (RSM) with the help of central composite design (CCD). The regression equation and analysis of variance were originated using Design-Expert software and F value (131.56), p-value (<0.05), and desirability value of 1 were obtained for the optimized model. Activated alumina adsorption has also been shown to be a promising arsenic removal technology (As5+) with 15 min of equilibrium time. An arsenic removal system was designed with EC unit, sand filter, and activated alumina column in series for field application. The field unit was able to deliver safe water to the local community. During the operation, the electrodes were passivated, and calcium-based deposition was found on the cathodes. Periodic electrode reversal was able to minimise the passivation. Due to the accumulation of ferric hydroxide flocs, the pores of the filter bed become clogged and they must be cleaned by backwashing. The Backwash system should be continued until the water runs clear. An arrangement of a suitable soak pit is made to contain the backwash water avoiding any environmental contamination. EC could be able to deliver safe water locally in rural areas at affordable prices due to its high efficiency and low operation and maintenance costs.

Efficiency of electrocoagulation in the treatment of laundromat greywater

ABSTRACT The high consumption of water and the generation of greywater in laundromats underscore the need to investigate advanced treatment techniques to reuse this effluent. Based on the estimated growth figures of the laundromat sector in Brazil, this study looked into the efficiency of electrocoagulation to treat laundromat greywater. Electrodes were connected to an EC reactor on a monopolar parallel connection mode, with electric current of 6 A and current density of 400 A.m2. The highest efficiency to treat laundromat greywater was observed at a distance of 15 mm between electrodes, voltage of 17.14 V, and operation time of 30 min, when the removal values of apparent color, true color, turbidity, biochemical oxygen demand, chemical oxygen demand, and surfactants were 92, 97, 88, 91, 98, and 96%, respectively. Electrode consumption was measured at 1.82 g.h, while energy consumption was 20.54 kWh.m3 and the total cost was US$ 4.10 per cubic meter of treated effluent. However, despite the high efficiency of the treatment, reuse of treated laundromat effluent requires polishing in order to meet the standards defined by Brazilian regulations.

The effects of ultrasound and electrocoagulation on removal of manganese from wastewater

In this paper the effect of ultrasound and electrocoagulation on the removal of manganese from synthetic wastewater was investigated. It was shown that 20 kHz ultrasound alone is not very efficient for manganese removal, but it enhances the efficiency of electrocoagulation. It was also shown that settling has a great effect on the electrocoagulation process because it stabilizes the flocs. A total of four laboratory-scale experiments were conducted, and the optimal experiment included 10 minutes of ultrasound and 10 minutes of electrocoagulation with iron electrodes. Under these conditions, 89.0 % of the manganese was removed with an operating cost of 0.13 EUR/mg Mn. Adding the cost of replacing the immersed ultrasonic probe, the total operating cost increased 3000-fold, making the immersed ultrasonic probe method unviable for large-scale application.