Treatment of oilfield wastewater by FentonÕs process

A combination of coagulation and Fenton's process was used for the removal of total oxygen carbon (TOC) from oilfield wastewater. Compared with aluminium sulfate, ferric coagulant had better TOC removal efficiency at the same mass dosage. In Fenton's process, the effect of H₂O₂ and Fe²⁺ dose on the removal of TOC was studied. The optimum conditions required for TOC removal were an Fe³⁺ concentration of 40-50 mg/L, an H₂O₂ dose of 50 mmol/L and an Fe²⁺ concentration of 1.0 mmol/L. GC-MS chromatographic analysis indicated that most of the alkyl hydrocarbons of carbon numbers <21 were removed in the first minute of FentonÕs process mainly through adsorption. Alkyl hydrocarbons and phenols were oxidized almost completely following 120 min of treatment. The pathway of newly formed intermediates in Fenton's process was proposed on the basis of the GC/MS chromatogram.