BACKGROUND AND OBJECTIVES: The increasing need for efficient wastewater treatment solutions has driven research toward the development of integrated processes capable of addressing complex contaminant compositions. Standard single-stage treatment approaches frequently do not effectively remove a variety of pollutants, including organic compounds, heavy metals, and pathogenic microorganisms. Furthermore, information on the integration of coagulation-flocculation, biofiltration, and advanced oxidation processes within a cohesive treatment system. This study aimed to develop and evaluate a multi-stage wastewater treatment system that combines coagulation-flocculation, biofiltration, and advanced oxidation processes to enhance pollutant removal efficiency and improve effluent quality.METHODS: The experimental setup consisted of three sequential treatment units. In the first stage, coagulation-flocculation was employed to aggregate and remove suspended solids and colloidal matter. Coagulant dosages of 20, 40, 60, and 100 milligrams per liter were tested to determine the optimal chemical requirement. The second phase employed biofiltration to enhance the biological breakdown of dissolved organic substances, with the hydraulic retention time fine-tuned for optimal microbial activity. The final stage applied ultraviolet light and hydrogen peroxide oxidation to degrade residual organic pollutants and ensure microbial disinfection. FINDINGS: As the dosage of coagulant was raised, the coagulation-flocculation performance showed improvement. At 20 milligrams per liter, total suspended solids removal was 52.3 percent and chemical oxygen demand reduction was 15.7 percent. At 40 milligrams per liter, these values increased to 72.8 percent and 28.4 percent, respectively. The optimal dosage of 60 milligrams per liter achieved 88.5 percent removal of total suspended solids and 39.6 percent reduction in chemical oxygen demand, while at 100 milligrams per liter, the efficiency reached 92.5 percent and 43.3 percent, respectively. The integrated multi-stage system achieved average overall removal efficiencies of 92 percent for chemical oxygen demand, 85 percent for heavy metals, and more than 99 percent for microbial inactivation. CONCLUSION: The findings indicate that the combined treatment system significantly improves pollutant removal by leveraging the synergistic interaction between physicochemical, biological, and oxidation processes. The study confirms the potential of the system for pilot-scale and full-scale adaptation, suggesting its viability as an integrated solution for effective wastewater management and the protection of public health.
Amankeshuly et al. (Thu,) studied this question.