Fenton Oxidation Process of Refractory Organics in Gas Processing Wastewater

IN THE CURRENT research, treatment of gas-associated wastewater (3,100 m³/d) from a gas production company located at Alexandria was carried out. The produced wastewater was found to be contaminated with high organic and inorganic pollutants, characterized by high COD (chemical oxygen demand) 55000 mg/L, low BOD (biochemical oxygen demand) 9500 mg/, TSS (total suspended solids) 385 mg/L and total phenols of 0.8 mg/L. The BOD/COD ratio of 0.17 proves that wastewater has hazardous organics that are hardly biodegradable. Due to the low TSS concentration, conventional coagulation precipitation method is not considered adequate.  A Fenton reagent [Fe²⁺/ H₂O₂] is proposed for degradation of existing soluble organics in the wastewater. Optimum operating conditions were: H₂O₂ in concentration of 1.6 M/L (one Stoichiometry with COD), 80 mM/L of Fe²⁺ ions, at pH around 3 and optimal time of 30 minutes. A corresponding residual concentration of COD and BOD were 11000 and 4000 mg/L and a complete removal of phenols. Results concluded that, Fenton reagent was found suitable to improve the biodegradability of the raw gas processingwastewater, BOD/COD increased from 0.17 to 0.36 and a complete removal of phenols has been achieved, making it feasible to be treated biologically in effective manner.