IJSRST1184893 | Received : 07 June 2018 | Accepted : 18 June 2018 | May-June-2018 [ 4 (8) : 517-525] © 2018 IJSRST | Volume 4 | Issue 8 | Print ISSN: 2395-6011 | Online ISSN: 2395-602X Themed Section: Science and Technology 517 Removal of Reactive Scarlet Dye and COD Using Cylindrical Iron Rod Anodes In A Semi-Continuous Reactor Ersin Aytac 1* , Umran Tezcan Un 2 1 Department of Environmental Engineering, Zonguldak Bülent Ecevit University, Zonguldak, Turkey 2 Department of Environmental Engineering, Eskisehir Technical University, Eskişehir, Turkey ABSTRACT The cylindrical iron electrochemical reactor for electrocoagulation (EC) of reactive scarlet dye was studied. In the study, 0.5 L synthetic wastewaters with a dye concentration of 200 mg/L and chemical oxygen demand of 620 mg/L (COD) prepared in laboratuary treated for 90 minutes of EC. The effects of operational parameters such as current density (10 - 30 mA/cm2), initial pH (5 - 9), flow rate (100 - 400 mL/min) and the supporting electrolyte concentration (0.05 - 0.2 M Na2SO4) were investigated. For each operation parameter, dye stuff concentration and chemical oxygen demand has been measured for removal efficiencies after treatment duration. To estimate the operating cost, the electrical energy consumption was calculated. It has been observed that current density has positive effect on removal efficiencies. Moreover adequate dye stuff removals has been achieved in short process time and low current efficiencies. When effect of the initial pH value of the wastewater was examined, it was observed that the optimum pH value was 7.1. When investigating the influence of flow rate it was found that higher flow rates has ngative effect by breaking up the aggregates. The lowest electrical energy consumptions has been established in 0.2 M Na2SO4 concentration for the effect of supporting electrolyte concentration. Effluent COD concentration of 22 mg/L with a removal efficiency of 96.5% and effluent dye concentration of 1.08 mg/L with a removal efficiency of 99.46% was obtained with an electrical energy consumption of 4.28x10-4 kWh/mg CODremoved. Additionally, the sludge produced at electrocoagulation was characterized and maghemite (Fe2O3) was found as most common species. Keywords : COD Removal, Decolorization, Electrochemical Treatment, Iron Electrode, Reactive I. INTRODUCTION Increasing population and industrialization can affect human life and the environment either positively or negatively. Engineering science is able to formulate the necessary precautions to ensure a sustainable environment and natural life. In the last few decades, new developments in treatment technologies have been seen. Development in wastewater treatment is essential for lessening the harmful effects of industrial waste on the environment. Electrocoagulation (EC), in conjunction with wastewater treatment processes, has become prominent in recent years. EC is an electro- chemical process in which electrically oxidized metals have the ability to form coagulants by combining with electrolyzed water, in situ. In fact, in EC, not only do metal hydroxides form as coagulants, but other mechanisms also occur. Floating and electro-chemical reactions are amongst these treatment mechanisms. Aluminum and iron electrodes are mostly used in EC because of their cost of effectiveness, availability and effectiveness in the formation of coagulants. The ion charge of oxidized metal can be different depending on the voltage applied. Reactions occurring with iron electrodes are shown below [1]; Mechanism I