Reliability Treatment of Silicon in Oilfield Wastewater by Electrocoagulation

Abstract

Scaling caused by silicate in oilfield wastewater gathering system pipelines can cause serious pipeline blockage. Therefore, this study adopts facile, effective and environment friendly electrocoagulation method to remove the silicon in oilfield wastewater. After confirming the level of factors through single factor experiments, the optimal scheme for electrocoagulation was selected by orthogonal experiments and verification tests, the silicon content would be dramatically decreased from 81.51 mg/L to 21.88 mg/L when pH = 6, reaction time = 20 min, current density = 27 mA/cm2 and wastewater temperature = 35 °C. In addition, the silicon removal rate would reach up to 85.90% when the pH of oilfield wastewater was kept as its original condition without changing other optimal factors; such an enhanced silicon removal effect could be attributed to the calcium ions chemical coagulation after the mechanism investigation.

Keywords

• high-silicon wastewater treatment
• electrocoagulation
• calcium ion
• orthogonal experiment