Petrochemical wastewater treatment by means of clean electrochemical technologies

The removal of chemical oxygen demand (COD), turbidity, phenol, hydrocarbon and grease from petrochemical wastewater (PCWW) was experimentally done by using electroflotation (EF) and electrocoagulation (EC). In the EF unit, a graphite anode and a stainless steel mesh as cathode were used. In the EC unit, iron and aluminium were used simultaneously as materials for two blocks of alternating electrodes. The reactor voltage was 12 V, current density (CD) was varied from 5 to 15 mA cm⁻², and the residence time varied in the limits of 2–20 min for EF and 1–10 min for EC. The results have shown that EC removes the mentioned contaminants from PCWW more effectively than EF. Turbidity removal in the process of PCWW purification was estimated as 83% for EF and 88% for EC. The yields of phenol, hydrocarbon and grease removal by EC were examined under different values of residence time, CD, and with iron and aluminium as materials for electrodes.