两级氧化法处理油田压裂返排液

采用两级氧化法处理油田压裂返排液。在次氯酸钠、次氯酸钙、过氧化氢、高锰酸钾4种氧化剂中，次氯酸钠的氧化效果最好。以次氯酸钠作为一级氧化剂，进行一级氧化处理;再分别采用次氯酸钙、过氧化氢、高锰酸钾进行二级氧化处理。在次氯酸钠加入量为40mL/L、一级氧化反应时间为30min、二级氧化反应时间为30min、初始废水COD为3976mg/L的条件下，二级氧化剂过氧化氢、次氯酸钙、高锰酸钾的最佳加入量分别为80，40，40mL/L，对应的COD去除率分别为82.60%，71.50%，83.50%。

Treatment of Oilfield Fracturing Flow-back Fluid by Two-stage Oxidation Process

Oilfield fracturing flow-back fluid was treated by two-stage oxidation process. Sodium hypochlorite has the best oxidation effect among the 4 oxidants of sodium hypochlorite,calcium hypochlorite,hydrogen peroxide,and potassium permanganate. Sodium hypochlorite was used as the first-stage oxidant and calcium hypochlorite,hydrogen peroxide,potassium permanganate were used separately as the second-stage oxidants. Under the conditions of sodium hypochlorite dosage 40 mL/L,first-stage oxidation time 30 min,second-stage oxidation time 30 min and initial wastewater COD 3 976 mg/L,the optimum dosages of hydrogen peroxide,calcium hypochlorite,potassium permanganate are 80,40,40 mL/L,and the COD removal rates are 82.6%,71.5%,83.5%,respectively.