In order to reduce the effluent COD and improve the biodegradability of the polymer flooding oil-extraction wastewater,the wastewater was pretreated by O_3/UV and O_3/H_2O_2 process.The effects of influential factors,such as oxidation time,mole ratio of O_3 and H_2O_2,pH and the power of UV light on the treatment of oil-field wastewater by O_3/UV and O_3/H_2O_2 were investigated.The results reveal that both of these two oxidation methods can improve the removal efficiency of COD and PAM of the wastewater mo...