Treatment of municipal wastewater of Fez city (Morocco) using a sequence of aerobic and Fenton processes

The study aims to assess the efficiency of applying the Fenton process to municipal wastewater from Fez city (Morocco), previously pretreated by the aerobic process. Experiments were carried out on a lab scale with batch reactors. The aerobic pretreatment was operated in a suspended growth bio-reactor and monitored periodically for several parameters. The process performance was evaluated based on chemical oxygen demand (COD), biochemical oxygen demand (BOD5), and UV-Visible absorption spectra. The aerobic bioreactor showed a high efficiency, with removals up to 67% and 100% for COD and BOD5, respectively. The Fenton process applied after aeration pretreatment suc-cessfully reduced the residual bio-resistant organics, and its efficiency was evaluated in terms of COD. Therefore, the integrated treatment of aeration and Fenton technologies, at optimal operat-ing conditions of the Fenton process (pH = 3, contact time = 60 min, FeSO4 dose = 3.57 mmol/L, and H2O2 dose = 14.71 mmol/L) achieved total COD, color and BOD5 removals of 86%, 90.3%, and 100%, respectively. Accordingly, UV-visible absorption spectra underwent a significant decrease due to the removal of organic substances. Indeed, the final measured COD was 117.3 mg/L, which complies with national and international standards for liquid disposal or reuse. Therefore, the proposed treatment train could be promising for raw wastewater remediation and environmental protection.