Study On Microeletrolysis And Fenton Coupling Process For Oilfield Fracturing Wastewater Treatment

Oilfield fracturing wastewater with high CODcr, high color, high viscosity and other characteristics does tremendous harm to the surrounding environment. This subject researches Micro electrolysis.Fenton oxidation coupling process on oilfield fracturing wastewater to discusse the optimal coupled mode and influence of pH, iron.carbon ratio, hydrogen peroxide dosage, reaction time on the treatment effect systematically. Then the optimum parameters are determined. The subject analyzes changes of the hydroxyl radical and iron ions concentration, and changes of effluent water quality, molecular weight distribution, IR and UV spectra before and after the reaction. So that it proves the reaction mechanism.The results showed that the optimum process is demulsification with potassium persulfate, micro electrolysis.Fenton coupled oxidation, coagulation and sedimentation. Adding hydrogen peroxide to micro.electrolysis three times is the best way of coupling. The optimal parameters are determined that 5g/Lof potassium persulfate dosage, pH=3, iron.carbon ratio 1: 2, 1000 mg / L of ferrous sulfate dosage and 150 min of reaction time. Total dosage of H₂O₂ is 5mL / L which is dosed three times, once every 30 min. The pH is adjusted to 10 with NaOH after the reaction. Efficiency of removing COD is up to 57% after coagulation sedimentation. During the Micro electrolysis.Fenton coupling reaction, a large number of hydroxyl radicals produce in a short time at the beginning of the reaction. There are Fe²⁺ ions in iron.carbon micro.electrolysis reaction, in which H₂O₂ generates ?OH that can accelerate oxidative degradation of organic matter. In addition, ?OH can oxidate Fe²⁺ ions to Fe³⁺ ions. The pH of wastewater containing Fe²⁺ and Fe³⁺ ions is adjusted to 10, which generate much new floc of Fe（OH）3 and Fe（OH）2 that can further degrade organic matter. This process mainly remove the benzene ring, double bond and triple bond, and oxidate macromolecules, middle molecules into small molecules. But removal of small molecules that the molecular weight is less than 3K is not effective.The Micro electrolysis─Fenton oxidation coupling process, treatment on oilfield fracturing wastewater, is a simple process that has good effect and can be applied to practice.