Treatment of Petrochemical Wastewater Containing Phenolic Compounds by Electrocoagulation Using a Fixed Bed Electrochemical Reactor

This work explores the possibility of using electrocoagulation to remove phenolic compounds from oil refinery waste effluent using an electrochemical reactor with a fixed bed anode made of randomly oriented Al raschig rings packed in a perforated plastic basket located above the horizontal cathode. The removal of phenolic compounds was investigated in terms of various parameters in batch mode namely: pH, operating time, current density, initial phenol concentration, addition of NaCl, temperature and the effect of phenol structure (effect of functional groups). The chemical oxygen demand (COD) was also measured. In order to throw some light on the economics of the process, energy consumption as well as Al consumption were calculated under different conditions. The study revealed that the optimum conditions for the removal of phenolic compounds were achieved at current density = 8.59 mA/cm2, pH = 7, NaCl concentration = 1 g/L and temperature of 25°C. Remarkable removal of 100% of phenol compound after 2 hrs can be achieved for 3 mg/L phenol concentration of real refinery wastewater. The new anode design of electrocoagulation cell permits high efficiencies with lower energy consumption in comparison with other cell design used in previous studies.