Combined Fenton oxidation and aerobic biological processes for treating a surfactant wastewater containing abundant sulfate

The present study is to investigate the treatment of a surfactant wastewater containing abundant sulfate by Fenton oxidation and aerobic biological processes. The operating conditions have been optimized. Working at an initial pH value of 8, a Fe2+ dosage of 600 mg L−1 and a H2O2 dosage of 120 mg L−1, the chemical oxidation demand (COD) and linear alkylbenzene sulfonate (LAS) were decreased from 1500 and 490 mg L−1 to 230 and 23 mg L−1 after 40 min of Fenton oxidation, respectively. Advanced oxidation pretreatment using Fenton reagent was very effective at enhancing the biodegradability of this kind of wastewater. The wastewater was further treated by a bio-chemical treatment process based on an immobilized biomass reactor with a hydraulic detention time (HRT) of 20 h after Fenton oxidation pretreatment under the optimal operating conditions. It was found that the COD and LAS of the final effluent were less than 100 and 5 mg L−1, corresponding to a removal efficiencies of over 94% and 99%, respectively.