Integrated Advanced Ozonation Technologies for Enhanced Total Organic Carbon Removal from Secondary Treated Municipal Wastewater: Systematic Optimization and Environmental Analysis

Abstract

Municipal wastewater, characterised by a complex matrix of organic contaminants, poses significant environmental challenges due to residual total organic carbon (TOC), a critical marker of persistent organic pollutants, even after secondary treatment. To address this issue, the investigation evaluates the efficiency of integrated advanced ozonation technologies combining ozone (O₃), ultraviolet (UV) irradiation, hydrogen peroxide (H₂O₂), and activated carbon (AC) for TOC removal from secondary-treated effluent. A predictive model optimised the process parameters, achieving a maximum TOC removal efficiency of 65.95% at an O₃ flow rate of 3.17 L/min, H₂O₂ dosage of 12.98 mM, UV exposure duration of 62.04 min, and AC dosage of 10.10 mg/L. In contrast, the lowest TOC removal of 39.55% ± 2.15% occurred under sub-optimal conditions, with an O₃ flow rate of 3 L/min, H₂O₂ dosage of 10 mM, UV exposure for 20 min, and 1 mg/L of AC. The economic and environmental analyses revealed the integrated process to be more cost-effective and sustainable compared to conventional single-step treatments. These findings highlight the potential of integrated advanced ozonation technologies for effective TOC removal, providing a pathway for enhanced wastewater treatment practices and improved environmental sustainability.

Graphical Abstract