Use of electrochemical oxidation process as post-treatment for the effluents of a UASB reactor treating cellulose pulp mill wastewater

2006 ◽  
Vol 54 (2) ◽  
pp. 207-213 ◽  
Author(s):  
A.P. Buzzini ◽  
D.W. Miwa ◽  
A.J. Motheo ◽  
E.C. Pires
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Oxidation Process ◽  
Pulp Mill ◽  
Electrochemical Treatment ◽  
Post Treatment ◽  
Uasb Reactor ◽  
Recirculation Flow ◽  
Cellulose Pulp ◽  
Uasb Reactors

The main purpose of this study was to evaluate the performance of the electrochemical oxidation process as a post-treatment for the effluents of a bench-scale UASB reactor treating simulated wastewater from an unbleached pulp plant. The oxidation process was performed using a single compartment cell with two plates as electrodes. The anode was made of Ti/Ru0.3Ti0.7O2 and the cathode of stainless steel. The following variables were evaluated: current density (75, 150 and 225 mA cm−2) and recirculation flow rate in the electrochemical cell (0.22, 0.45 and 0.90 L h−1). The increase in current density from 75 to 225 mA cm−2 did not increased the color removal efficiency for the tested flow rates, 0.22, 0.45 and 0.90 L h−1, however the energy consumption increased significantly. The results indicated the technical feasibility of the electrochemical treatment as post-treatment for UASB reactors treating wastewaters from pulp and paper plants.

Assessment of electrochemical and chemical coagulation as post-treatment for the effluents of a UASB reactor treating cellulose pulp mill wastewater

2005 ◽  
Vol 52 (1-2) ◽  
pp. 183-188 ◽  
Author(s):  
A.P. Buzzini ◽  
A.J. Motheo ◽  
E.C. Pires
Keyword(s):  
Kraft Pulp ◽  
Pulp Mill ◽  
Post Treatment ◽  
Color Removal ◽  
Uasb Reactor ◽  
Cellulose Pulp ◽  
Aluminium Sulfate ◽  
Treatment Processes ◽  
Simulated Wastewater ◽  
Electrolytic Treatment

This paper presents results from exploratory experiments to test the technical feasibility of electrolytic treatment and coagulation followed by flocculation and sedimentation as post-treatment for the effluent of an UASB reactor treating simulated wastewater from an unbleached Kraft pulp mill. The electrolytic treatment provided up to 67% removal of the remaining COD and 98% of color removal. To achieve these efficiencies the energy consumption ranged from 14 Wh.l−1 to 20 Wh.l−1. The coagulation-flocculation treatment followed by settling required 350–400 mg.l−1 of aluminium sulfate. The addition of a high molecular weight cationic polymer enhanced both COD and color removal. Both post-treatment processes are technically feasible.

scholarly journals Electrochemical oxidation as a post treatment for biologically tannery wastewater in batch reactor

2019 ◽  
Vol 80 (7) ◽  
pp. 1326-1337 ◽  
Author(s):  
Tran Le Luu ◽  
Djeuga Djeuga Franck Stephane ◽  
Nguyen Hoang Minh ◽  
Nguyen Duc Canh ◽  
Bui Xuan Thanh
Keyword(s):  
Energy Consumption ◽  
Electrochemical Oxidation ◽  
Organic Compounds ◽  
Current Density ◽  
Batch Reactor ◽  
Post Treatment ◽  
Pollutant Removal ◽  
Tannery Wastewater ◽  
Stirring Rate ◽  
A Current

Abstract Tannery wastewater is known to contain high concentrations of organic compounds, heavy metals, nitrogen, sulphur, chromium, and many other chemicals. Both aerobic and anaerobic biological approaches have proven ineffective in the treatment of tannery wastewater due to the high salinity and toxic chemicals contained within the medium. Electrochemical oxidation presents a promising method for solving this problem. High pollutant removal efficiency, low energy consumption, and high electrode stability are three important factors supporting the feasibility of an efficient electrochemical treatment process. In the present study, electrochemical oxidation was performed as a post treatment for tannery wastewater (after biological pre-treatment) in a batch reactor using Ti/RuO2, Ti/IrO2, and Ti/BDD anodes. The effects of pH, current density, stirring rate and treatment time were studied to assess the treatment efficiency as well as the energy consumption of the process. The results showed that colour, chemical oxygen demand (COD), total organic carbon (TOC), and total nitrogen (TN) removal efficiencies on the electrodes were: Ti/RuO2 (88.8%, 88.40%, 64.0%, 96.4%), Ti/IrO2 (85.40%, 85.9%, 52.3%, 51.4%), Ti/BDD (90.60%, 94.7%, 90.5%, 82.7%) respectively, at a current density of 80 mA/cm2. All three electrodes demonstrated optimal performance at a pH of 8, a stirring rate of 400 rpm, a current density of 80 mA/cm2, and an electrolysis time of 5 h. The concentration of tri-chloromethane by-product was detected with limiting value. Electrochemical oxidation thus offers a feasible method for removing organic compounds and nutrients from tannery wastewater.

scholarly journals Elucidation and Characterization of New Chlorinated By-Products after Electrochemical Degradation of Hydrochlorothiazide Using Graphite–Poly Vinyl Chloride Electrode

Catalysts ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 540
Author(s):  
Zainab Mussa ◽  
Fouad Al-Qaim ◽  
Ali Yuzir ◽  
Hirofumi Hara ◽  
Shamila Azman ◽  
...  
Keyword(s):  
Electrochemical Oxidation ◽  
Treatment Process ◽  
Oxidation Process ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Experimental Conditions ◽  
E Coli ◽  
Flight Mass Spectrometry ◽  
Negative Ionization ◽  
By Products

This paper describes an electrochemical treatment process of hydrochlorothiazide (HDZ) under different conditions such as initial concentration, sodium chloride and applied voltage. In this present study, HDZ was treated by electrochemical oxidation process using graphite-PVC composite electrode as anode and Platinum (Pt) as cathode. All results were analyzed using liquid chromatography-time of flight/mass spectrometry (LC-TOF/MS). It was found that at high applied voltages, and high amounts of NaCl, the electrochemical treatment process was more efficient. The removal% of HDZ was 92% at 5 V after 60 min. From the obtained results, the electrochemical oxidation process of HDZ followed pseudo first order with rate constant values ranged between 0.0009 and 0.0502 min−1, depending on the experimental conditions. Energy consumption was also considered in this study, it was ranged between 0.9058 and 5.56 Wh/mg using 0.5, 0.3 and 0.1 g NaCl within interval times of (10, 20, 30, 40, 50, 60, 70, and 80 min). Five chlorinated and one non-chlorinated by-products were formed and analyzed in negative ionization (NI) mode during the electrochemical process. Due to the strong oxidizing potential of the chlorine (Cl2) and hypochlorite ion (ClO−), HDZ and its by-products were removed after 140 min. Furthermore, a novel synthesis of chlorothiaizde as one of the new by-products was reported in this present study. Toxicity was impacted by the formation of the by-products, especially at 20 min. The inhibition percentage (I%) of E. coli bacteria was decreased to be the lowest value after 140 min.

Destruction of refractory humic acid by electromechanical oxidation process

2000 ◽  
Vol 42 (3-4) ◽  
pp. 225-232 ◽  
Author(s):  
L.-C. Chaing ◽  
J.-E. Chang ◽  
T.-Cn. Wen
Keyword(s):  
Humic Acid ◽  
Electrochemical Oxidation ◽  
Humic Substance ◽  
Current Density ◽  
High Efficiency ◽  
Oxidation Process ◽  
Chloride Concentration ◽  
Chloride Ion ◽  
Gel Permeation Chromatography ◽  
Indirect Oxidation

Electrochemical oxidation of humic acid has been conducted to evaluate the efficacy of the process for the destruction of high-molecular-weight (HMW) compounds. Experimental results show that the destruction of humic acid obtained by the electrolysis supported by chloride ion is much better than that obtained by sulfate ion. Accordingly, HMW compound such as humic substance is suggested to be resistant to directly anodic oxidation, but to be readily destroyed by an indirect oxidation of chlorine/hypochlorite during an electrochemical treatment process. The effects of operating parameters, including anode material, current density, electrolyte concentration, have been investigated in this study. A tertiary-oxide of Sn, Pd, Ru coated titanium (SPR) anode with high electrocatalytic activity was found to have high efficiency for humic acid destruction, and the destruction efficacy of humic substance increased with increasing current density and chloride concentration. In this study, gel permeation chromatography (GPC) and adsorptive organic halide (AOX) had been performed to examine the variation of organic characteristics during the electrochemical oxidation of humic acid. The results from GPC and AOX show that HMW organic compounds could be effectively destroyed by electrochemical oxidation process, and the process also produced less undesirable chlorinated byproducts than the chlorination process. From the above results, the electrochemical oxidation conducted by indirect oxidation effect of chlorine/hypochlorite could be concluded to be a feasible method for the destruction of HMW compounds.

UASB-Process Design for Various Types of Wastewaters

1991 ◽  
Vol 24 (8) ◽  
pp. 87-107 ◽  
Author(s):  
G. Lettinga ◽  
L. W. Hulshoff Pol
Keyword(s):  
Process Design ◽  
Reactor Design ◽  
Domestic Sewage ◽  
Post Treatment ◽  
Uasb Reactor ◽  
Wastewater Purification ◽  
Different Types ◽  
Uasb Reactors

In this paper the design of UASB-reactors is discussed for different types of wastewater, viz. industrial soluble non-complex wastewaters, SS-rich complex wastewaters and domestic sewage. The paper not only deals with the UASB-reactor design, but also with other treatment steps, pre- as well as post-treatment, that are required for as complete as possible overall wastewater purification.

A Dual Cathode Electro Fe2+/S2O82- System Used for Pickle Sauerkraut Wastewater Degradation

2014 ◽  
Vol 1073-1076 ◽  
pp. 924-928
Author(s):  
Shu Yun Shi ◽  
Hong Hui Teng
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Treatment Effect ◽  
Oxidation Process ◽  
Removal Rate ◽  
Cod Removal ◽  
Test Results ◽  
Effect Test ◽  
Plate Distance ◽  
Electrode Plate

Using novel dual cathode/electro/Fe2+/S2O82-system to treat pickle sauerkraut wastewater, the paper investigates the influencing factors (S2O82-dosage, Fe2 +dosage, current density, Wastewater pH, electrode plate distance) of the organic matters removal and the treatment effect. Test results show that the degree of various factors influence on COD removal of sauerkraut wastewater is different. The COD removal is little effected by pH, while largely effected by current density, dosage of Fe2 +and S2O82-dosage. Under the optimum experiment conditions, current density for 30mA/cm-2, dosage of Fe2 +for 8mmol/L, S2O82-dosage for 12 mmol/L, electrode plate distance for 2 cm and pH=6, sixty minutes electrolysis, wastewater removal rate reach up to 92.6%. These results suggest that this electrochemical oxidation process by dual cathode/electro-Fe2+-S2O82-system might provide an alternative for the degradation of pickle sauerkraut wastewater.

scholarly journals Application of Taguchi’s experimental design method for optimization of Acid Red 18 removal by electrochemical oxidation process

2018 ◽  
Vol 5 (4) ◽  
pp. 241-248 ◽  
Author(s):  
Zabihollah Yousefi ◽  
Ali Zafarzadeh ◽  
Abdolaziz Ghezel
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Oxidation Process ◽  
Design Method ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Fractional Factorial ◽  
Synthetic Wastewater ◽  
Electro Oxidation ◽  
Electro Coagulation

Background: Electro-oxidation is developed as an electrochemical method to overcome the problems of the conventional decolorization technologies and is an appropriate alternative for the treatment of colored wastewater from various industries. The purpose of this study was to evaluate the efficiency of the electrochemical oxidation process in removal of chemical oxygen demand (COD) and Acid Red 18 (AR18) dye from aqueous solutions. Methods: In this research, a laboratory scale of electro-coagulation reactor for the treatment of synthetic wastewater was made and studied. The effects of different variables including pH, current density, dye concentration, and electrolysis time were investigated. The experiment steps were designed by DesignExpert 10 software using the selected variables. Finally, the dye and COD analysis was performed by spectrophotometer. The optimization was performed using Taguchi fractional factorial design during the removal of dye and COD. Results: Maximum removal of dye (89%) and COD (72.2%) were obtained at pH=3, current density=20 mA/cm2 , initial dye concentration=100 mg/L, and reaction time=45 min. ANOVA test showed a significant relationship between statistical model and test data. Also, the results indicate that the distribution of the residues of the model was normal. Conclusion: By designing experiments through Taguchi method, the removal process will be optimized and by decreasing the number of experiments, the optimal conditions for pollutant removal will be prepared. The results suggest that the Electro-oxidation system is a very suitable technique for the enhancement of wastewater treatment.

scholarly journals Performance of UASB reactors in two stages followed by post-treatment with activated sludge in wastewater batch of wet-processed coffee

2013 ◽  
Vol 33 (4) ◽  
pp. 808-819 ◽  
Author(s):  
Marcelo Bruno ◽  
Roberto A. de Oliveira
Keyword(s):  
Activated Sludge ◽  
Post Treatment ◽  
Upflow Anaerobic Sludge Blanket ◽  
Uasb Reactor ◽  
Anaerobic Sludge ◽  
Nitrogen And Phosphorus ◽  
Removal Efficiencies ◽  
Two Stages ◽  
Anaerobic Sludge Blanket ◽  
Uasb Reactors

In this study it was evaluated the efficiency of the treatment of wet-processed coffee wastewater in upflow anaerobic sludge blanket (UASB) reactors in two stages, in bench scale, followed by post-treatment with activated sludge in batch. The first UASB reactor was submitted to an hydraulic retention time (HRT) of 6.2 d and organic loading rates (OLR) of 2.3 and 4.5g CODtotal (L d)-1, and the second UASB reactor to HRT of 3.1 d with OLR of 0.4 and 1.4g CODtotal (L d)-1. The average values of the affluent CODtotal increased from 13,891 to 27,926mg L-1 and the average efficiencies of removal of the CODtotal decreased from 95 to 91%, respectively, in the UASB reactors in two stages. The volumetric methane production increased from 0.274 to 0.323L CH4 (L reactor d)-1 with increment in the OLR. The average concentrations of total phenols in the affluent were of 48 and 163mg L-1, and the removal efficiencies in the UASB reactors in two stages of 92 and 90%, respectively, and increased to 97% with post-treatment. The average values of the removal efficiencies of total nitrogen and phosphorus were of 57 to 80% and 44 to 60%, respectively, in the UASB reactors in two stages and increased to 91 and 84% with the post-treatment.

Electrochemical oxidation pretreatment of refractory organic pollutants

1997 ◽  
Vol 36 (2-3) ◽  
pp. 123-130 ◽  
Author(s):  
Li-Choung Chiang ◽  
Juu-En Chang ◽  
Shu-Chuan Tseng
Keyword(s):  
Electrochemical Oxidation ◽  
Current Density ◽  
Oxidation Process ◽  
Supporting Electrolyte ◽  
Chloride Concentration ◽  
Gel Permeation Chromatography ◽  
Organic Halogen ◽  
Removal Efficiencies ◽  
Refractory Organic Pollutants ◽  
Microtox Test

Refractory pollutants, including lignin, tannic acid, chlortetracycline, and EDTA, were destroyed by an electrochemical oxidation method to evaluate the applicability of this method for industrial wastewater pretreatment. Operation parameters, such as supporting electrolyte, current density, and electrolyte concentration, have been investigated for their influences on COD removal efficiencies during electrolysis. In addition, gel permeation chromatography (GPC), Microtox test, and total organic halogen (TOX) analyses were performed to monitor the changes of organic characteristics of these refractory pollutants. Experimental results show that, among sulfate, nitrate, and chloride, chloride was the best supporting electrolyte, and during electrolysis, both COD and color removal efficiencies were improved by increasing current density and chloride concentration. From GPC analysis results, the electrochemical oxidation process readily destroys high-molecular-weight (HMW) organics. Microtox test results also show that the process can reduce the toxicity of these refractory organic compounds. In addition, TOX concentrations were found to increase at the beginning but then decline during the electrolysis. The above results suggest that the electrochemical oxidation process, which has good efficacy for detoxification and destruction of refractory pollutants, is a promising method for wastewater pretreatment.

In situ surface reconstruction synthesis of a nickel oxide/nickel heterostructural film for efficient hydrogen evolution reaction

2020 ◽  
Vol 56 (72) ◽  
pp. 10529-10532
Author(s):  
Haixin Chen ◽  
Dongqi Ge ◽  
Junwei Chen ◽  
Ruchun Li ◽  
Xiaofeng Zhang ◽  
...  
Keyword(s):  
Nickel Oxide ◽  
Electrochemical Oxidation ◽  
Hydrogen Evolution ◽  
Surface Reconstruction ◽  
Hydrogen Evolution Reaction ◽  
Current Density ◽  
Oxidation Process ◽  
Large Current ◽  
Large Current Density

In situ reconstruction of NiO/Ni@CC has been successfully achieved through an electrochemical oxidation process, which exhibits a significantly improved HER performance and good stability even at a large current density.

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