Evaluation of the Effects of Experimental Parameters on COD Removal from Leachate Water by Electrocoagulation Process

Since leachate is a complex and highly variable wastewater, it is the most difficult to treat in

wastewater. Electrochemical processes are among the most preferred methods in leachate

treatment. The most preferred electrode materials are aluminum and iron, as they are

economical, effective and easily soluble in the electrocoagulation process. In the case of using

aluminum electrodes, it produces Al3+ and Al(OH)2+ species, which are initially converted to

Al(OH)3 and subsequently converted to Aln(OH)3n as a result of the electrolytic dissolution of

the aluminum electrode. In this study, the effects of current density, initial pH, distance between

electrodes, mixing speed and initial temperature on COD removal efficiency were investigated.

Experimental studies were used in a 20cmx8cmx10cm reactor made of plexiglass. The

electrodes are arranged in a monopolar parallel arrangement with three anodes and three

cathodes. In the COD analysis, the standard method used is the SM 5220.D Closed Reflux

Colorimetric method. In the experiments, COD removal efficiencies were determined according

to current density 15-25 mA/cm2, pH 3-9.5, temperature 20-60oC, stirring speed 100-300 rpm,

distance between electrodes 1-2 cm. In the light of the data obtained, the highest turbidity

removal efficiency was determined as 62% at current density 20 mA/cm2, pH 5, initial

temperature 20°C, distance between electrodes 1 cm, stirring speed 300 rpm. It can be said that

this is due to the tendency of aluminum to hydrolyze and adsorb colloidal structures on the

surface of the electrode. Thus, it can be said that the electrocoagulation process is a suitable

process for turbidity removal from leachate.