Oilfield Produced Water Treatment by Ozone-Enhanced Flocculation

Due to the difficulty of oilfield produced water treatment and low efficiency of coagulation technology. A more efficient treatment technology was necessity. Produced water treatment by ozone enhanced coagulation was investigated in this study in order to develop a new method for oilfield produced water treatment. The results showed that addition of ozone could reduce the dosage of coagulant (PAC) and flocculant (PAM) to get the same pollutant removal rate, resulting in lower running cost. pH could affect oil and SS removal. Acid circumstance was helpful to pollutant removal and the optimal temperature was 50°C. Addition of contact filler to the reaction tank could improve ozone utilization and granular activated carbon was the best packing material in this research. Presence of oxygen could increase corrosion speed and Na₂S₂O₃ could be used to remove residual oxygen generated from the ozonation. When Na₂S₂O₃ dosage was 40mg/L and the reaction time was 20min, oxygen content in the effluent could below 0.5mg/L. In summary, ozone could enhance coagulation and the ozone enhanced coagulation technology could be used to treat oilfield produced water.