Treatment of oilfield production wastewater by an integrated process

Laboratorial scale experiments were performed to investigate the performance of an integrated process including demulsification, coagulation, and reactive oxygen species (ROS) oxidation for treating oilfield waste drilling fluid. The optimum dosages for demulsifier, polyaluminium chloride and polyacrylamide are 2, 0.6 and 3 mg/L, respectively. The optimum ROS oxidation conditions are ROS molecules content = 350 mg/L, energy consumption = 30 Wh, reaction time = 40 min, and initial pH = 6.5. Results show that 96.3% of oil can be recovered from the waste, and the quality of the final effluent can satisfy the national discharge standard after ROS oxidation.