To meet wastewater treatment quality standards for reuse, integrating advanced oxidation processes (AOPs) with Decentralized Wastewater Treatment Systems (DEWATS) is promising. This study aimed to optimize AOPs (ozonolysis, UV photolysis, TiO photocatalysis) for polishing anaerobic filter (AF) effluent from DEWATS, as an alternative to constructed wetlands. Metrics included pathogen reduction efficiency, post-disinfection regrowth, and effects on physical parameters (pH, EC, turbidity), organic matter (soluble COD, BOD, DOC, humic), and nutrient concentration (ammonium, nitrates, ortho-P). Ozonolysis and TiO photocatalysis achieved a 6.4-log pathogen reduction, while UV photolysis achieved a 6-log. No pathogen regrowth occurred with ozonolysis, but TiO photocatalysis showed and Total coliforms regrowth of 2.5-log and 2.7-log, respectively. UV photolysis showed 0.5-log and 2.2-log regrowth for and Total coliforms, respectively. TiO photocatalysis significantly reduced BOD, soluble COD, humic substances, ortho-P, turbidity, and nitrates, while increasing pH, EC, ammonium, and DOC. Ozonolysis significantly lowered BOD, soluble COD, humics, and turbidity, but increased ortho-P, nitrates, pH, EC, ammonium, and DOC. UV-photolysis showed marginal reductions in BOD, nitrates, and turbidity, with increased EC, pH, ammonium, DOC, ortho-P, and humic levels. Ozonolysis emerged as the best AOP, demonstrating efficient effluent treatment with no pathogen regrowth.
