Experimental design of wastewater treatment with electro-coagulation

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.

2017 ◽  
Vol 76 (5) ◽  
pp. 1124-1131 ◽  
Author(s):  
Tao Wang ◽  
Tianqing Liu

Pulse electro-coagulation (PEC) was applied to treat plastic factory wastewater in this study. One representative plasticizer molecule was chosen for the synthetic wastewater: dibutyl phthalate (DBP). Experiments demonstrated that PEC exhibits superior economic efficiency and removal efficiency compared to traditional electro-coagulation in wastewater treatment. Experimental data also indicated that at a given current density, compared with the aluminum electrode, the iron electrode could more efficiently remove DBP from wastewater. With an initial pH of 8–9, the required energy was 2.5 kWh m−3 for 75% DBP removal in the case of iron as the anode type. In general, the pollutants have been successfully reduced to environmentally acceptable levels under the following operating conditions: iron as the anode type, interelectrode distance of 10 mm, duty cycle of 0.6, pH of 8–9 and current density of 15 mA cm−2 for PEC time >15 min.


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.


2013 ◽  
Vol 9 (3) ◽  
pp. 1988-1999
Author(s):  
Ukiwe L.N ◽  
Ibeneme S.I ◽  
Duru C.E ◽  
Okolue B.N ◽  
Onyedika G.O ◽  
...  

Chemical and electrocoagulation are widely used coagulation methods employed in water and wastewater treatment. Both coagulation processes are effective in removing a wide range of impurities which include dissolved organic matter in form of chemical and biological oxygen demand, pathogens, oils, and colloidal particles as well as heavy metals. The present review has revealed that the mode of action of both coagulation methods is based on charge neutralization and floc formation. The effectiveness of both coagulation techniques depend on factors such as pH, coagulation dose, coagulant type, current density, applied voltage, water and wastewater  type, type of electrode, as well as size and number of electrodes. The commonly used chemical coagulants are inorganic coagulants based on aluminum and iron salts. However, there have been considerable successes in the development of pre-hydrolyzed inorganic coagulants which have the added advantage over traditional inorganic coagulants in that they function well over a wide range of pH and water temperatures. Electrocoagulation has been proposed as an alternative method to chemical coagulation because it is environmental friendly and cheap to operate. Nonetheless, most researchers are of the opinion that there are still some uncertainties regarding the understanding of its optimal performance and design mechanism.


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).


2018 ◽  
Vol 13 (4) ◽  
pp. 753-763 ◽  
Author(s):  
A. Y. Gören ◽  
M. S. Öncel ◽  
E. Demirbas ◽  
E. Şık ◽  
M. Kobya

Abstract The aim of this research was to remove arsenate (As(V)) from groundwater using an air-injected electrocoagulation (EC) reactor with aluminum (Al) ball anodes. The effects of seven operating variables – initial pH, applied current (i), operating time (tEC), initial As(V) concentration (Co), Al ball anode diameter (dp), reactor column height (h), and airflow rate (Qair) were investigated with a Box-Behnken statistical experimental design. ANOVA results from the quadratic model equations indicated that the model fitted very well with the experimental data for the responses, which were removal efficiency, operating cost (OC), As(V) adsorption capacity, and effluent concentration (R2 ≥ 0.87). The most effective parameters were applied current, operating time, and anode height for As(V) removal efficiency in the EC reactor, while initial pH, Al anode diameter, and air flow rate had limited effect on removal. The model predicted a residual As(V) concentration below 10 μg/L under the optimum operating conditions (pH 7.03, 0.29 A, 10.5 min, dp 7.5 mm, 613.4 μg/L, h 5.1 cm, and Qair 6.4 L/min). The maximum As(V) removal efficiency and minimum OC in the EC process were almost 99% and 0.442 $/m3, respectively.


2019 ◽  
Vol 79 (12) ◽  
pp. 2366-2377 ◽  
Author(s):  
Hanife Sari-Erkan

Abstract This study mainly focuses on the process of electrocoagulation (EC) for the wastewater treatment from biodiesel production using waste cooking oil. The effects of current density, initial pH and electrolysis time on the EC process using aluminum (Al) and iron (Fe) electrodes were investigated for removal of chemical oxygen demand (COD). The COD removal efficiencies were found to be 62.7% and 63.4% at optimum conditions for Al (current density: 43 mA/cm2, pH: 5, time: 21 min) and Fe (current density: 47 mA/cm2, pH: 7.7, time: 30 min) electrodes, respectively. At these optimum conditions, the removal efficiencies of oil & grease, total phosphorus (TP), orthophosphate (PO4-P) and total suspended solids (TSS) were determined respectively to be above 89.9%, 98.9%, 99.5%, 86.7% for Al electrodes and 90.8%, 98.5%, 97.6%, 89.6% for Fe electrodes. Total operating costs were also found to be 6.43 €/m3 and 7.01 €/m3 for Al and Fe electrodes, respectively. The results indicate that the EC process using both types of electrodes seems to ensure an efficient treatment of biodiesel wastewater in terms of oil & grease and TP.


2018 ◽  
Author(s):  
Caitlyn Johnston ◽  
William E. Davis

In the present study, we examined how the influence of exercise-related social media content on exercise motivation might differ across content type (with images vs. without images) and account type (individual vs. corporate). Using a 2 × 2 within-subjects experimental design, 229 participants viewed a series of 40 actual social media posts across the four conditions (individual posts with images, corporate posts with images, individual posts without images, and corporate posts without images) in a randomized order. Participants rated the extent to which they felt each social media post motivated them to exercise, would motivate others to exercise, and was posted for extrinsic reasons. Participants also completed other measures of individual differences including their own exercise motivation. Posts with images from individuals were more motivating than posts with images from corporations; however, corporate posts without images were more motivating than posts without images from individuals. Participants expected others to be similarly motivated by the stimuli, and perceived corporate posts as having been posted for more extrinsic reasons than individuals’ posts. These findings enhance our understanding of how social media may be used to promote positive health behaviors.


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