Hybrid Bio–AOP Systems for Wastewater Treatment: Experimental Evaluation and Sustainability Assessment

Abstract

This study evaluates a hybrid biological–advanced oxidation process (bio–AOP) system for municipal wastewater treatment under controlled laboratory conditions. The influent, characterized by relatively high COD (518 mg/L), BOD₅ (242 mg/L), nutrients, heavy metals, pharmaceuticals, and microplastics, reflects typical conditions in North African medium-sized cities. Compared with a biological-only baseline, the hybrid configuration achieved significantly higher removals (COD 89.7%, BOD₅ 94.5%, pharmaceuticals and heavy metals >70%, microplastics ~80%) while producing 30% less sludge and reducing the carbon footprint by 34%. Although the system required higher energy input (0.29 vs. 0.13 kWh/m³), its broad-spectrum removal capacity makes it promising for water reuse in water-scarce regions. Furthermore, the results highlight potential impacts on microbial community dynamics during sequential treatment.