Treatment of Polymer Flooding Oil-Extraction Wastewater by O₃/UV and O₃/H₂O₂ Oxidation

In order to reduce the effluent COD and improve the biodegradability of the polymer flooding oil-extraction wastewater,the wastewater was pretreated by O₃/UV and O₃/H₂O₂ process.The effects of influential factors,such as oxidation time,mole ratio of O₃ and H₂O₂,pH and the power of UV light on the treatment of oil-field wastewater by O₃/UV and O₃/H₂O₂ were investigated.The results reveal that both of these two oxidation methods can improve the removal efficiency of COD and PAM of the wastewater more obviously compared with single ozone.The improvement of the biodegradability of the wastewater by O₃/H₂O₂ was the most obvious.Taking into account of practical engineering application,under the following conditions:pH=8.0,O₃ concentration was 19.7 mg/L,reaction time was 30 min at 18 W UV lamp irradiation,B/C was up to 0.092 by O₃/UV process.And under the following conditions:pH=8.0,O₃ concentration was 19.7 mg/L,reaction time was 30 min and mole ratio of O₃ and H₂O₂ was 0.3,B/C was up to 0.175 by O₃/H₂O₂ process.The biodegradability of oil-field wastewater was obviously increased by oxidation pretreatment,which could reduce the pressure of follow-up biochemical treatment.