Advanced Treatment of Coking Wastewater by Electro-Coagulation

2014 ◽  
Vol 700 ◽  
pp. 426-430 ◽  
Author(s):  
Hai Tang ◽  
Jun Peng Sha ◽  
Yang Long Ou ◽  
Xiang Zhao

The degradation behavior and mechanism of biologically pretreated coking wastewater (BPCW) were investigated by means of a lab-scale electro-coagulation (EC) in static methods. The results showed that the percent COD and color removal can reach 80.5 % and 95.4 % respectively under the optimal conditions (initial pH of 8.0; reaction time of 30 min; current density of 14.0 mA/cm2 and NaCl dosage 1.6 g/L).

2013 ◽  
Vol 726-731 ◽  
pp. 2515-2520 ◽  
Author(s):  
De Min Yang ◽  
Jian Mei Yuan

Advanced treatment of biochemical treated coking wastewater was studied experimentally with ozonation process. The effects of initial pH value, ozone concentration, reaction temperature, and reaction time on the COD and color removal rate were investigated. The results showed that ozonation was an effective method for advanced treatment of biochemical treated coking wastewater. The increasing of initial pH value, ozone concentration, reaction temperature, and reaction time has enhanced the removal rate of COD and color. Meanwhile, the results also revealed that the maximal COD and color removal rate of 69.65% and 92.27% could be reached under the optimal conditions of the initial pH value is 10.5, ozone concentration is 150 mg/L, reaction temperature is 298 K, and reaction time is 30 min.


2011 ◽  
Vol 183-185 ◽  
pp. 417-421
Author(s):  
Yong Bo Lin ◽  
Yang Yang ◽  
Shuai Wang

Determined to adopt iron as anodes, and Ti-base board with coating as cathodes. To optimize the reaction conditions of phosphorus removal by electrocoagulation (EC), testing the effect of current density, electrode distance, initial pH and electrolysis time on the phosphorus removal. According to the results, the optimal conditions for the phosphorus removal in the EC treatment were obtained, i.e., 20 mA/cm2 of current density, 2cm of distance and 10min of reaction time were optimum. Under these conditions, phosphorus removal by electrocoagulation reached to 95.07%, 10min later the change of total phosphorus (TP) removal rate is not obvious. By the end of this test, phosphorus removal by electrocoagulation reached to 99.68%.


2018 ◽  
Vol 78 (6) ◽  
pp. 1260-1267 ◽  
Author(s):  
Mohammad Malakootian ◽  
Mohammad Reza Heidari

Abstract Phenol and its derivatives are available in various industries such as refineries, coking plants, steel mills, drugs, pesticides, paints, plastics, explosives and herbicides industries. This substance is carcinogenic and highly toxic to humans. The purpose of the study was to investigate the removal of phenol from wastewater of the steel industry using the electrocoagulation–photo-Fenton (EC-PF) process. Phenol and chemical oxygen demand (COD) removal efficiency were investigated using the parameters pH, Fe2+/H2O2, reaction time and current density. The highest removal efficiency rates of phenol and COD were 100 and 98%, respectively, for real wastewater under optimal conditions of pH = 4, current density = 1.5 mA/cm2, Fe2+/H2O2 = 1.5 and reaction time of 25 min. Combination of the two effective methods for the removal of phenol and COD, photocatalytic electrocoagulation photo-Fenton process is a suitable alternative for the removal of organic pollutants in industry wastewater because of the low consumption of chemicals, absence of sludge and other side products, and its high efficiency.


2019 ◽  
Vol 93 ◽  
pp. 02005 ◽  
Author(s):  
Madhuri Damaraju ◽  
Debraj Bhattacharyya ◽  
Tarun Panda ◽  
Kiran Kumar Kurilla

A continuous bipolar mode electrocoagulation (CBME) unit was used in this study for polishing a biologically treated distillery wastewater at laboratory scale. This study focuses on optimizing the process for removal of Total Organic Carbon (TOC) from an anaerobically-treated distillery wastewater. Response surface methodology (RSM) was used for optimizing the process. The study was conducted by varying three operating parameters: Initial pH (2-10), reaction time (0.5-15 min), and current density (13-40 A/sqm). High R-square values, above 0.9, were obtained with ANOVA. Optimal point was observed to be at pH-6.04, Reaction time-11.63 min, current density-39.2 A/sqm. Experimental values of TOC removal at optimal point were found to be 73% against maximum predicted value of 79%. Color removal efficiency was observed to be 85% at the optimal points. It can be concluded that CBME system can be a suitable alternative for removal of recalcitrant carbon and color post-biological treatment in distillery wastewaters.


2011 ◽  
Vol 63 (3) ◽  
pp. 385-394 ◽  
Author(s):  
E. GilPavas ◽  
I. Dobrosz-Gómez ◽  
M. Á. Gómez-García

The capacity of the electro-coagulation (EC) process for the treatment of the wastewater containing Cr3+, resulting from a leather tannery industry placed in Medellin (Colombia), was evaluated. In order to assess the effect of some parameters, such as: the electrode type (Al and/or Fe), the distance between electrodes, the current density, the stirring velocity, and the initial Cr3+ concentration on its efficiency of removal (%RCr+3), a multifactorial experimental design was used. The %RCr3+ was defined as the response variable for the statistical analysis. In order to optimise the operational values for the chosen parameters, the response surface method (RSM) was applied. Additionally, the Biological Oxygen Demand (BOD5), the Chemical Oxygen Demand (COD), and the Total Organic Carbon (TOC) were monitored during the EC process. The electrodes made of aluminium appeared to be the most effective in the chromium removal from the wastewater under study. At pH equal to 4.52 and at 28°C, the optimal conditions of Cr3+ removal using the EC process were found, as follows: the initial Cr3+ concentration=3,596 mg/L, the electrode gap=0.5 cm, the stirring velocity=382.3 rpm, and the current density=57.87 mA/cm2. At those conditions, it was possible to reach 99.76% of Cr3+removal, and 64% and 61% of mineralisation (TOC) and COD removal, respectively. A kinetic analysis was performed in order to verify the response capacity of the EC process at optimised parameter values.


2010 ◽  
Vol 159 ◽  
pp. 499-504 ◽  
Author(s):  
Yi Zheng ◽  
Zhuo Zhang ◽  
Hong Tao Hu ◽  
Xia Liang Wei

An integrated technique was investigated, aiming to provide an effective method for the treatment of biologically treated coking wastewater and to reduce pollutants to concentration values below the limits imposed by the legislation. Coking wastewater containing 270 mg/L COD and 202 times color was treated by coagulation using PAC as well as PAC +PAM, respectively. The application of coagulation using PAC+PAM resulted to a much more efficient removal of color, COD and SS in comparison with single coagulation without PAC. The optimal condition for coagulation with PAC was pH 8, dosage 75 mg/L and dynamic condition 1-minute high speed stirring followed by 15-minute low speed stirring. The optimal condition for coagulation with PAC and PAM was: PAM dosage of 6 mg/L, PAC dosage of 70 mg/L, pH of 8 and reaction time of 20 minutes. Both processes of coagulation were found to be efficient for removal of COD from coking wastewater, but ineffective in reducing color.


2017 ◽  
Vol 17 (6) ◽  
pp. 1703-1711 ◽  
Author(s):  
E. Karamati Niaragh ◽  
M. R. Alavi Moghaddam ◽  
M. M. Emamjomeh

Abstract This study aims to investigate the effect of the main parameters on the performance of a continuous flow electro-coagulation (EC) process for nitrate removal efficiency and its operating costs. For this purpose, the Taguchi experimental design with orthogonal array L27 (313) was applied to analyze the effects of selected parameters, namely initial nitrate concentration, inlet flow rate, current density and initial pH. According to the analysis of variance results, the inlet flow rate and the current density were recognized to be the most effective factors playing a pivotal role in nitrate removal efficiency by using an EC process. The optimum conditions of initial nitrate concentration, inlet flow rate, current density and initial pH were found to be 100 mg/L, 50 mL/min, 80 A/m2 and 8, respectively. As a result, the observed nitrate removal efficiency under these conditions was 61.70%. In addition, operating costs were evaluated as 1.278 US$/g NO3-removed. Finally, a high correlation was observed between the experimental and predicted results indicating an appropriate accuracy of the Taguchi model for nitrate removal efficiency and its operating costs in an EC system.


2018 ◽  
Vol 77 (10) ◽  
pp. 2463-2473
Author(s):  
Yanyan Li ◽  
Mengjuan Li ◽  
Jing Lu ◽  
Xiaoqiang Li ◽  
Mingqiao Ge

Abstract Disperse Red 60 simulated polyester alcoholysis liquid decoloration by electro-Fenton with Fe3O4 catalyst was studied. The influences of the main operating parameters such as catalyst dosage (0.3–0.9 g/L), current density (60–120 mA/cm2) and pH (1–7) were optimized by response surface methodology (RSM) based on Box–Behnken surface statistical design (BBD). In optimal conditions, the initial concentration of 25 mg/L disperse red polyester alcoholysis liquid was catalyzed by 0.6 g/L Fe3O4, and the decoloration efficiency was 97.18% with the current density of 90 mA/cm2 and initial pH of 4.6. There was a relative error of 1.18% with the predicted model when the predictive value was 98.25% under the same conditions. In addition, ultraviolet-visible absorption spectra (UV-Vis), Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were used to study the degradation mechanism during decoloration. The intermediates were identified and the proposed degradation pathways were investigated by liquid chromatography-mass spectrometry (LC-MS) analysis.


2012 ◽  
Vol 599 ◽  
pp. 313-317
Author(s):  
Juan Wang ◽  
Ling Fei Fan ◽  
Di Fan

In this study, we presented an approach to coking wastewater advanced treatment process with a patented wastewater treatment equipment. The samples were collected from the effluents of the biological treatment tank in a coking wastewater treatment plant. With the experiments of four static single factors and the continuing dynamic process, the discussions about the effects of pH value, influent loading, reaction time, and volume ratio on chromaticity, COD and NH3-N respectively were conducted. The experimental results identified that the optimum process parameters were pH of 3, influent load of 1m3/m2•h, reaction time of 4h and volume ratio of 2:1 respectively. When influents of chromaticity, COD and NH3-N were 210 times, 249.4mg/L, and 31.7mg/L respectively , the effluent of chromaticity, COD and NH3-N were 16 times, 49.7mg/L, and 9.5mg/L respectively, these values could meet the National standard of Recycling and Miscellaneous usages of Municipal Sewage on chromaticity, COD and NH3-N requirements.


2014 ◽  
Vol 25 (1) ◽  
pp. 86-95 ◽  
Author(s):  
Sule Camcioglu ◽  
Lutfiye Canan Pekel ◽  
Kamran Polat ◽  
Hale Hapoglu

Purpose – The purpose of this paper is to investigate the batch treatment of pulp and paper mill wastewater using electro-coagulation (EC). Design/methodology/approach – Statistical experimental design was used to investigate the effect of initial pH, current density and temperature. Experiments were planned to obtain the maximum amount of information in the fewest number of runs. Minimum-maximum values of current density, initial pH, temperature of medium were selected as 9-25 mA/cm2, 5-9, 25-50°C, respectively. A total number of 20 experiments including eight factorial points, six axial points and six replicates in centre points were carried out and experimental data were collected. Optimum operating parameters were determined by evaluating experimental results in MATLAB 7.9®. Findings – According to the results, the optimum values of current density, initial pH and temperature of medium are determined as 14.12 mA/cm2, 8.22 and 34.21°C, respectively. Practical implications – Many researches about different techniques including physical, chemical and biological methods have been done on the subject of pulp and paper wastewater treatment. In physical and chemical processes low molecular weight compounds are not removed efficiently, also these methods are quite expensive. Electrochemical degradation has an advantage of removing even the smallest colloidal particles compared with traditional flocculation and coagulation. Originality/value – Complete removal of pollutants, less sludge generation, simple process design and easy operation are standard features of the EC and it comes forward as one of the promising techniques.


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