Study on Treatment of Reverse Osmosis Concentrate of Petrochemical Wastewater by Homogeneous-Fenton Process

The homogeneous Fenton process was applied to the treatment of petrochemical reverse osmosis concentrate (ROC). The effects of H₂O₂ concentration, Fe²⁺ concentration, initial pH value and reaction temperature on the treatment efficiencies were investigated, and the biodegradability of wastewater and the variations characteristics of the pollutants analyzed. The results showed that under the optimum reaction conditions of H₂O₂ concentration 75.0 mmol/L, Fe²⁺ concentration 7.5 mmol/L, initial pH value 3.0 and reaction temperature 25 ℃, after 2.0 h reaction, TOC concentration decreased from 198.4 mg/L to 111.6 mg/L, the organics mineralization removal efficiency reached 43.7%, and the BOD₅/COD_Cr ratio increased from 0.11 to 0.28. The biodegradability of ROC was significantly improved and the concentration of the pollutants greatly decreased. The excitation-emission matrix (EEM) spectrum analysis demonstrated that the total removal efficiency of the fluorescence organics by homogeneous Fenton process reached 78.7%, which improved the biodegradability of the wastewater.