| An enhanced oil recovery (EOR), including polymer and ASP flooding, has been greatly used in oilfields in China. Due to containing hydrolized polyacrylamide (HPAM), wastewater from EOR processes is characteryed of high concentration, high viscosity and high emulsification. And the effects are increased with high degree of hydrolysis. Many simple isolation techniques are not ideal. In this research, a new technique of Fenton reagent oxidation was investigated to EOR wastewater. The factor of temprature, pH, H2O2, Fe2+, and sodium tartrate concentration were studied on HPAM. At the same time, we studied practical wastewater during polymer and ASP flooding. Degradation rate of HPAM in wastewater was investigated. The processing factors were optimized. The results show that UV/Fenton/tartrate system is an optimal technology. The conditions set to 10:1:1 of UV/Fenton/tartrate, 120min of time, 3 of pH and 22.0℃ of temperature. In addition, we deduce that the high concentration of HPAM obviously inhibits the reaction. By Using UV/Fenton/tartrate system, the remaining of HPAM in the wastewater of polymer flooding was less than 30% when the oxidative reagents were added to 10Qth. The removal of HPAM decreased with increasing of pH. The stepwise addition of reagents is much effective. The removal of oil is easier than that of HPAM. The removal of oil is 20% higher than that of HPAM. The higher pH value is, the more effective the degradation of oil is. The most effective is 7 of pH. With UV/Fenton/tartrate system, the removal of HPAM in the wastewater of ASP flooding is increased when Fenton's reagent rises. When the oxidative reagent grows from Qth to 2Qth, the removal of HPAM increases obviously. But the degradation of HPAM is not obvious when the dose is 3Qth. By using UV/Fenton/tartrate system, the removal of oil is greater than the degree of degradation of HPAM in the wastewater of ASP flooding. The removal of oil is bigger than 90%. The concentration of oil is smaller than 30mg/L. |
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