Oilfield produced water treatment by ozone-enhanced flocculation

摘要

Due to the difficulty of oilfield produced water treatment and low efficiency of coagulation technology, a more efficient treatment technology was necessary. 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. The "pH" could affect oil and suspended solid (SS) removal. Acid circumstance was helpful to pollutant removal and the optimal temperature was 50 ℃. Addition of contact filler to the reaction tank could improve ozone utilization rate and granular activated carbon was the best packing material in this research. Presence of oxygen could increase corrosion speed and Na_2S_2O_3could be used to remove residual oxygen generated from the ozonation. When Na_2S_2O_3 dosage was 40 mg/L and the reaction time was 20 min, oxygen content in the effluent could below 0.5 mg/L. In summary, ozone could enhance coagulation and the ozone enhanced coagulation technology could be used to treat oilfield produced water.