Novel Electrode Design for Removing CNG Lubricant from Wastewater by Using Electrocoagulation

Abstract

Lube oil centres are producing a huge quantity of oily wastewaters in Egypt. Compressed natural gas (CNG) lubricant and car park stations are the main source of mineral oily wastewater. A huge quantity of oily wastewater formed during the replacement of engine's lubricant. The treatment of such oily wastewater which contains CNG lubricant has been carried out via Electrocoagulation (EC) with a novel electrode design was investigated. The finely dispersed oil removal from oil/water emulsions by EC using electrolytic cell with novel Al horizontal electrodes is studied. The cell is consisted mainly of a cylindrical plastic container (25 cm in height and 10 cm diameter), a vertical Al sheet as cathode placed at the bottom of the cell and rotating disc as anode. The cathode-anode apart was fixed at a distance of 1.5 cm. Different variables are studied such as the rotational speed of anode (100 - 500 rpm), NaCl dose as an electrolyte, pH, oil emulsion concentration, voltage and time applied. The maximum removal obtained is 87.5% for operating conditions at pH 7.4, initial oil concentration 500 ppm, rpm 480 and 0.5% NaCl; respectively. Although the present data were obtained using batch cell, but it can be utilized in practice to operate a continuous cell providing a flowrate of CNG lubricant wastewater to the cell was extremely low.