Decolorization of a reactive dye solution and treatment of a textile wastewater by electrocoagulation and chemical coagulation: Techno-economic comparison

Abstract

In this study, the effects of operational parameters such as initial pH, current density, electrolysis time, and initial dye concentrations on the decolorization of Reactive Yellow 135 (RY 135) solutions and the treatment of a textile wastewater by electrocoagulation (EC) with aluminum electrodes were investigated separately. Total organic carbon (TOC) and dye removal ratios were used to measure the treatment efficiency. Energy and electrode consumptions were calculated per m3 of dye solution and per kg of pollutant removed. Amount of sludge produced after EC was also reported per m3 of dye solution. For a complete technical analysis, chemical coagulation experiments with aluminum salts were also carried out. Different direct and indirect cost items including energy, sacrificial electrodes, labor, sludge handling and disposal, maintenance, and depreciation costs have been considered in the calculation of the total operating cost. Under the optimum parameters found in this study, 0.23 $/m3 of total operating cost was acquired with 81% of COD, 85% of TOC, 93.7% of turbidity, and 97.1% of TSS removal efficiencies in treatment of the textile wastewater with EC. 0.11 kWh/m3 of energy and 0.03 kg/m3 of aluminum were consumed while 0.15 kg/m3 of sludge were produced in the process. (C) 2011 American Institute of Chemical Engineers Environ Prog, 2011