scholarly journals Electrochemical treatment for greywater reuse: effects of cell configuration on COD reduction and disinfection byproduct formation and removal

2018 ◽  
Vol 19 (3) ◽  
pp. 891-898 ◽  
Author(s):  
Dina M. Drennan ◽  
Raji E. Koshy ◽  
David B. Gent ◽  
Charles E. Schaefer
Keyword(s):  
Current Density ◽  
Water Reuse ◽  
Energy Demand ◽  
Removal Rate ◽  
Cod Removal ◽  
Haloacetic Acids ◽  
Mixed Metal Oxide ◽  
Disinfection Byproduct ◽  
Cell Configuration ◽  
Ec Cells

Abstract Electrochemical (EC) treatment presents a low-energy, water-reuse strategy with potential application to decentralized greywater treatment. This study focused on evaluating the impacts of cell configuration, current density, and cathode material on chemical oxygen demand (COD) removal and disinfection byproduct (DBP) formation in greywater. The formation and/or cathodic removal of active chlorine, perchlorate, haloacetic acids, and trihalomethanes were assessed during EC treatment. DBP formation was proportional to current density in undivided EC cells. Sequential anodic-cathodic treatment in divided EC cells resulted in COD removal in the catholyte and anolyte. The anodic COD removal rate (using a mixed metal-oxide anode) was greater than the cathodic removal rate employing boron-doped diamond (BDD) or graphite cathodes, but anodic and cathodic COD removal was similar when a stainless-steel cathode was used. The overall energy demand required for 50% COD removal was 24% less in the divided cells using the graphite or BDD cathodes (13 W-h L−1) compared to undivided cells (20 W-h L−1). Perchlorate formation was observed in undivided experiments (>50 μg/L), but not detected in divided experiments. While haloacetic acids (HAAs) and trihalomethanes (THMs) were generated anodically; they were removed on the cathode surface in the divided cell. These results suggest that divided configurations provide potential to mitigate DBPs in water reuse applications.

scholarly journals Removal of the Rhodamine B Dye at Ti/Ru0.3Ti0.7O2 Anode Using Flow Cell System

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Ali Baddouh ◽  
Brahim El Ibrahimi ◽  
Elhassan Amaterz ◽  
M. Mohamed Rguiti ◽  
Lahcen Bazzi ◽  
...  
Keyword(s):  
Current Density ◽  
Rhodamine B ◽  
Removal Rate ◽  
Flow Cell ◽  
Cell System ◽  
Cod Removal ◽  
Color Removal ◽  
Ion Concentration ◽  
Applied Current ◽  
Rhodamine B Dye

The electrochemical oxidation of the Rhodamine B dye (Rh-B) was carried out using dimensionally stable type anode (DSA, Ti/Ru0.3Ti0.7O2). The work was performed using the electrochemical flow cell system. The effect of several operating factors, such as supporting electrolytes, current density, electrolysis time, temperature, and initial concentration of Rh-B dye, were investigated. The UV-visible spectroscopy and chemical oxygen demand (COD) measurements were conducted to monitor the removal and degradation of Rh-B. The best color removal achieved was found to be 98.3% after 10 min applying 3.9 mA·cm−2 as a current density using 0.07 mol·L−1 of NaCl. Meanwhile, the highest COD removal rate (93.0%) was obtained for an applied current density of 3.9 mA·cm−2 as the optimal operating condition after 180 min reaction time, with 2.98 kW h·m−3 as energy consumption. This shows that the best conditions for color removal are not certainly the same as those for the COD removal. The rises in the concentration of NaCl, and applied current increased the Rh-B color removal rate. The decline in Rh-B dye concentration followed pseudo-first-order kinetics. The obtained values of apparent rate constant were increased by increasing chloride ion concentration. It is concluded that the electro-oxidation on DSA electrode using a flow cell is a suitable process for the removal of Rh-B dye in aqueous solutions.

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 Electrocoagulation: A Promising Method to Treat and Reuse Mineral Processing Wastewater with High COD

Water ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 595 ◽  
Author(s):  
Gaogui Jing ◽  
Shuai Ren ◽  
Yuesheng Gao ◽  
Wei Sun ◽  
Zhiyong Gao
Keyword(s):  
Current Density ◽  
Water Reuse ◽  
Removal Rate ◽  
Mining Industry ◽  
Mineral Processing ◽  
Sulfide Mineral ◽  
Industrial Applications ◽  
Promising Method ◽  
Treated Wastewater ◽  
Untreated Wastewater

Mineral processing wastewater contains large amounts of reagents which can lead to severe environmental problems, such as high chemical oxygen demand (COD). Inspired by the wastewater treatment in such industries as those of textiles, food, and petrochemistry, in the present work, electrocoagulation (EC) is applied for the first time to explore its feasibility in the treatment of wastewater with an initial COD of 424.29 mg/L from a Pb/Zn sulfide mineral flotation plant and its effect on water reuse. Typical parameters, such as anode materials, current density, initial pH, and additives, were characterized to evaluate the performance of the EC method. The results showed that, under optimal conditions, i.e., iron anode, pH 7.1, electrolysis time 70 min, 19.23 mA/cm2 current density, and 4.1 g/L activated carbon, the initial COD can be reduced to 72.9 mg/L, corresponding to a removal rate of 82.8%. In addition, compared with the untreated wastewater, EC-treated wastewater was found to benefit the recovery of galena and sphalerite, with galena recovery increasing from 25.01% to 36.06% and sphalerite recovery increasing from 59.99% to 65.33%. This study confirmed that EC is a promising method for the treatment and reuse of high-COD-containing wastewater in the mining industry, and it possesses great potential for wide industrial applications.

Research of 6-Nitry Industrial Wastewater Treatment by Coagulation-Fenton Oxidation

2012 ◽  
Vol 518-523 ◽  
pp. 2745-2748
Author(s):  
Ling Yan Ren ◽  
Gang Xu
Keyword(s):  
Treatment Effect ◽  
Industrial Wastewater ◽  
Removal Rate ◽  
Sulfate Solution ◽  
Cod Removal ◽  
Fenton Oxidation ◽  
Fenton Reagent ◽  
Oxidation Treatment ◽  
Cod Removal Rate ◽  
Solution Acidity

The paper adopted Coagulation-Fenton Oxidation Method on treating the wastewater of 6-nitro-1,2 diazonium oxygroup naphthalene-4-sulfoacid production process (i.e. 6-nitry wastewater), introduced the treatment effect of the combined technology used on 6-nitry wastewater, and studied the factors influencing the treatment effect, to determine the reasonable parameters of the technology on treating 6-nitry wastewater. The results showed that Using polyaluminium chloride (mass fraction 2%) as flocculant for treating 6-nitry wastewater, the COD removal rate reached up to 48.7%; Making Fenton reagent oxidation treatment on coagulation yielding water, under the best conditions for solution acidity controlled at pH3 or so, in the 100 mL wastewater, 30% hydrogen peroxide was 5.0 mL, 0.5 mol/L ferrous sulfate solution was 4.0 mL, reaction time was 60 min, the COD removal rate could reach 98% or more.

Study on Spray on Degradation of TNT-RDX Explosives Wastewater by Synergetic Ozonation

2013 ◽  
Vol 726-731 ◽  
pp. 2316-2319
Author(s):  
Hai Xia Duan
Keyword(s):  
Gas Phase ◽  
Removal Rate ◽  
Droplet Diameter ◽  
Cod Removal ◽  
The Self ◽  
Cod Removal Rate

TNT-RDX wastewater is hard to biodegrade and highly toxic. The self-made reactor was used to degrade the wastewater, spray and the conditions of droplet diameter, number of nozzle, spray height were clearly observed. The results show that the average COD removal rate of TNT-RDX wastewater was 69.6%.The spray conditions can improve the dispersion of the wastewater and increase the use of the residual ozone in gas phase. Keywords: Spray; TNT-RDX wastewater; ozone; UV; GAC

Application of Biofilm Kinetics to Anaerobic Fixed Bed Reactors

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1319-1326 ◽  
Author(s):  
I. E. Gönenç ◽  
D. Orhon ◽  
B. Beler Baykal
Keyword(s):  
Removal Rate ◽  
Fixed Bed ◽  
Experimental Studies ◽  
Pilot Scale ◽  
Cod Removal ◽  
Experimental Results ◽  
Fixed Bed Reactor ◽  
Removal Mechanism ◽  
Term Operation ◽  
Fixed Bed Reactors

Two basic phenomena, reactor hydraulics and mass transport through biofilm coupled with kinetic expressions for substrate transformations were accounted for in order to describe the soluble COD removal mechanism in anaerobic fixed bed reactors. To provide necessary verification, experimental results from the long term operation of the pilot scale anaerobic reactor treating molasses wastewater were used. Theoretical evaluations verified by these experimental studies showed that a bulk zero-order removal rate expression modified by diffusional resistance leading to bulk half-order and first-order rates together with the particular hydraulic conditions could adequately define the overall soluble COD removal mechanism in an anaerobic fixed bed reactor. The experimental results were also used to determine the kinetic constants for practical application. In view of the complexity of the phenomena involved it is found remarkable that a simple simulation model based on biofilm kinetics is a powerful tool for design and operation of anaerobic fixed bed reactors.

scholarly journals Study on the effect of electrocatalytic oxidation treatment of 2,4,6-Trinitrophenol wastewater

2018 ◽  
Vol 238 ◽  
pp. 03003
Author(s):  
Yaling Li ◽  
Wenqiang Jiang ◽  
Ruyu Li
Keyword(s):  
Current Density ◽  
Electrocatalytic Oxidation ◽  
Electrolyte Concentration ◽  
Removal Rate ◽  
Pharmaceutical Chemical ◽  
Oxidation Treatment ◽  
Titanium Electrode ◽  
First Order Kinetics ◽  
Oxidation Technology ◽  
Aromatic Nitro

2,4,6-Trinitrophenol is a toxic aromatic nitro-compounds that widely used in pharmaceutical, chemical and pesticide production. Due to its stable structure and poor biodegradability, advanced electrocatalytic oxidation technology was selected to treat simulated wastewater. The goal of the present work is to optimize the electrolysis conditions such as current density, electrolysis pH, and electrolyte concentration. A Pt modified TiO2 electrode was chosen as the anode accompanied with a titanium electrode of the same size as the cathode The results showed that the removal efficiency of 2,4,6-Trinitrophenol was the highest when the current density was 20mA/cm2, electrolyte pH=5, electrolyte concentration was 2 g/L. Under the optimal condition, the removal rate of 2,4,6-Trinitrophenol reached 99.76% after 120 minutes electrolysis. The decay of TNP could also be described by the pseudo-first-order kinetics formula with respect to TNP concentration. Therefore, electrocatalytic oxidation technology might provide an effective method for the degradation of nitroaromatic organic compounds.

COD removal efficiency and mechanism of HMBR in high volumetric loading for ship domestic sewage treatment

2016 ◽  
Vol 74 (7) ◽  
pp. 1509-1517 ◽  
Author(s):  
Linan Zhu ◽  
Hailing He ◽  
Chunli Wang
Keyword(s):  
Removal Efficiency ◽  
Removal Rate ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Domestic Sewage ◽  
Cod Removal ◽  
Aeration Tank ◽  
Remarkable Effect ◽  
Cod Removal Efficiency ◽  
Volumetric Loading

The hybrid membrane bioreactor (HMBR) has been applied in ship domestic sewage treatment under high volumetric loading for ship space saving. The mechanism and influence factors on the efficiency, including hydraulic retention time (HRT), dissolved oxygen (DO) of chemical oxygen demand (COD) removal were investigated. The HMBR's average COD removal rate was up to 95.13% on volumetric loading of 2.4 kgCOD/(m3•d) and the COD concentration in the effluent was 48.5 mg/L, far below the International Maritime Organization (IMO) discharge standard of 125 mg/L. DO had a more remarkable effect on the COD removal efficiency than HRT. In addition, HMBR revealed an excellent capability of resisting organics loading impact. Within the range of volumetric loading of 0.72 to 4.8 kg COD/(m3•d), the effluent COD concentration satisfied the discharge requirement of IMO. It was found that the organics degradation in the aeration tank followed the first-order reaction, with obtained kinetic parameters of vmax (2.79 d−1) and Ks (395 mg/L). The original finding of this study had shown the effectiveness of HMBR in organic contaminant degradation at high substrate concentration, which can be used as guidance in the full scale of the design, operation and maintenance of ship domestic sewage treatment devices.

scholarly journals Study of COD Removal Rate on a Sequencing Batch Reactor (SBR) Treating Tapioca Wastewater

2019 ◽  
Vol 38 (3) ◽  
pp. 243
Author(s):  
Happy Mulyani ◽  
Gregorius Prima Indra Budianto ◽  
Margono Margono ◽  
Mujtahid Kaavessina
Keyword(s):  
Wastewater Treatment ◽  
Sequencing Batch Reactor ◽  
Removal Rate ◽  
Batch Reactor ◽  
Cod Removal ◽  
Operation Condition ◽  
Effluent Quality ◽  
Aeration Time ◽  
Standard Quality ◽  
Cod Removal Rate

Industrial wastewater treatment using Sequencing Batch Reactor (SBR) can improve effluent quality at lower cost than that obtained by other biological treatment methods. Further optimization is still required to enhance effluent quality until it meets standard quality and to reduce the operating cost of treatment of high strength organic wastewater. The purpose of this research was to determine the effect of pretreatment (pH adjustment and prechlorination) and aeration time on effluent quality and COD removal rate in tapioca wastewater treatment using SBR. Pretreatment was done by (1) adjustment of tapioca wastewater pH to control (4.92), 7, and 8, and (2) tapioca wastewater prechlorination at pH 8 during hour using calcium hypochlorite in variation dosages 0, 2, 4, 6 mg/L Cl2, SBR operation was conducted according to following steps: (1) Filling of pre-treated wastewater into a bioreactor during 1 hour, and (2) aeration of the mixture of tapioca wastewater and activated sludge during 8 hours. Effluent sample was collected at every 2-hours aeration for COD analysis. COD removal rate mathematical formula was got by first deriving the best fit function between aeration time and COD. Optimum aeration time resulting in no COD removal rate. The value of COD effluent and its removal rate in optimum aeration time was used to determine the recommended of operation condition of pretreatment. Research result shows that chosen pH operation condition is pH 8. Prechorination can make effluent quality which meets standard quality and highest COD removal rate. The chosen Cl2 dosage is 6 mg/L.

A Study of Fenton’s Oxidation Pretreatment on Dye Wastewater Containing Acetic Acid

2014 ◽  
Vol 1044-1045 ◽  
pp. 215-218
Author(s):  
Xian Huan Qiu ◽  
Hai Yu ◽  
Peng Fei Deng
Keyword(s):  
Acetic Acid ◽  
Processing Time ◽  
Ph Value ◽  
Removal Rate ◽  
Cod Removal ◽  
Dye Wastewater ◽  
Fenton’S Oxidation ◽  
Effects Of Ph ◽  
Cod Removal Rate ◽  
Fenton's Oxidation

In the presence of acetic acid, the effects of pH, processing time, addition of Fe2+ and H2O2 on dye wastewater treatment were studied. Experimental results showed that in the presence of acetic acid, when the pH value was 4, the processing time was 30.0min, addition of ferrous sulfate was 4.8g/L, and addition of hydrogen peroxide was 56mL/L, the treatment effect was the best, COD removal rate reached 51.0%. Further studied of the effect of the presence of acetic acid on Fenton’s oxidation of dye wastewater, the results showed that without of acetic acid, the COD removal rate was higher than that with acetic acid. And the effect of Fenton's reagent on oxidation of dye substances was interfered by the presence of acetic acid.

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