Selenium removal from petroleum refinery wastewater using an electrocoagulation technique.

In the present work, an electrocoagulation technique was tested as a possible technological alternative for the treatment of selenium in wastewater from a petroleum refinery. For this purpose, a batch airlift reactor with air stirring was used. The sacrificial electrodes were made of iron to generate the necessary ferrous ions for the process. The results indicated a selenium removal of 90% from the wastewater after 6 h of treatment, achieving a decrease in concentration from 0.30 mg L to 0.03 mg L. The current density was found to be an important variable for the process. In conclusion, the electrocoagulation process seems to be a feasible selenium removal technique applied to petroleum refinery wastewater.