Comparative experimental evaluation of sequential biological-UV/H₂O₂ treatment for endocrine-disrupting chemical mixtures under controlled batch conditions.

The study evaluates the degradation of a mixture of frequently detected endocrine disrupting chemicals in municipal wastewater using six sequential biological-advanced oxidation treatment systems. The evaluated systems include UV, H2O2, and UV/H2O2 applied before or after biological treatment. The performance of the conventional municipal treatment plant was compared with sequential processes under previously optimized operating conditions (pH ≈ 5 (AOP), 7 (bio), 450 W UV power, 2.0 mM H₂O₂, reaction time for AOP: 60 min, and bio process: 6 h). The conventional system achieved only 36.41 ± 0.53% to 55.11 ± 0.48% removal of the mixture of target EDCs, whereas the bio/UV/H2O2 was the most effective, achieving complete diethyl phthalate removal and >90 ± 0.65% of butyl paraben and bisphenol A, with 90.5 ± 1.33% reduction in chemical oxygen demand. The pseudo-first-order kinetic analysis indicated an enhanced degradation efficiency, with a maximum rate constant of 0.0048 min-¹. The energy consumption ranged from 9.47 × 10² to 1.56 × 10⁴ kWh kg-¹ COD, with the operating cost primarily driven by electricity (≈0.16 USD L-¹). These findings provide mechanistic and comparative insight into hybrid treatment performance under controlled conditions; however, validation under environmentally relevant concentrations and continuous-flow systems is required before practical implementation.