Simultaneous removal of organic and inorganic pollutants in tannery wastewater using electrocoagulation technique

Abstract

Tannery wastewater can cause severe environmental problems related to its high chemical oxygen demand, high biochemical oxygen demand, high total suspended solids, high oil and grease contents together with the elevated chromium concentration and objectionable color. The one-step electrocoagulation process was carried out to simultaneously remove chromium and various pollutants from tannery wastewater at ambient temperature in the laboratory scale. Low-cost commercial iron plates were employed in this study as anodes and cathode materials. Effects of various parameters were investigated including types of electrode configuration, initial pH of wastewater (7-9), current density (15.7-24.6 Am −2 ) and circulating flow rate of wastewater (0-3.67 lmin −1 ). The optimum condition was found by applying the mono-polar electrode in a parallel connection at the current density of 22.4 Am −2 , flow rate of wastewater of 3.67 lmin −1 and 20 min electrolysis time. The initial pH of wastewater ranging from 7-9 provided the similar removal efficiency. At optimum condition, more than 95% of chromium and pollutants except TKN and TDS were eliminated from the wastewater and the properties of the treated wastewater met the standard and permitted to discharge into the environment. The required energy consumption at optimum condition was less than 0.13 kWhm −3 wastewater. In addition, the COD reduction was fit very well with the first-order kinetics model.

Treatment of Leachate by Electrocoagulation Technique Using Iron And Hybrid Electrodes

“…Based on the mentioned characteristics, tannery wastewater can be severely problematic for environment. Thus one of the functions of electrocoagulation process was removing different contaminants and chromium from tannery wastewater at the ambient temperature of the laboratory, simultaneously with other EC performances (Kongjao et al, 2008) …”

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“…During the tanning process, chromium salt is used to convert hides into leather and the wastewater generated contains huge amount of organic matter, phenolics, tannins and toxic heavy metals mainly chromium (Ma et al, 2015;Kongjao et al, 2008;Nithya and Sudha, 2016). This wastewater containing a variety of toxic pollutants when discharged into the environment causes serious…”

Simultaneous removal of trichloroethylene and hexavalent chromium by green synthesized agarose-Fe nanoparticles hydrogel

“…However, most removal processes are designed for treating only one specific contaminant in current applications. To the best of our knowledge, only a few reports have investigated the simultaneous removal of organic and inorganic contaminants [1,2,15,16]. These studies have proved useful in examining the removal of mixed contaminants but some drawbacks have emerged in these methods, for example high cost, inefficiency, and generating toxic sludge [2].…”