This study mainly evaluated the effectiveness of ozonation toward the enhancement of the removal efficiencies of antibiotic-resistant bacteria (ARB), pB10 plasmid transfer, and pB10 plasmids under different pH and suspended solids (SS) and humic acid concentrations. First, chlorination was tested as a reference disinfection process. Chlorination at a very high dose concentration of Cl2 (75 mg L(-1)) and a long contact time (10 min) were required to achieve approximately 90% ARB and pB10 plasmid transfer removal efficiencies. However, even these stringent conditions only resulted in a 78.8% reduction of pB10 plasmid concentrations. In case of ozonation, the estimated CT (concentration × contact time) value (at C0 = 7 mg L(-1)) for achieving 4-log pB10 plasmid removal efficiency was 127.15 mg·min L(-1), which was 1.04- and 1.25-fold higher than those required for ARB (122.73 mg·min L(-1)) and a model nonantibiotic resistant bacterial strain, E. coli K-12, (101.4 mg·min L(-1)), respectively. In preventing pB10 plasmid transfer, ozonation achieved better performance under conditions of higher concentrations of humic acid and lower pH. Our study results demonstrated that the applicability of CT concept in practice, conventionally used for disinfection, might not be appropriate for antibiotic resistance control in the wastewater treatment process. Further studies should be conducted in wastewater engineering on how to implement multiple barriers including disinfection to prevent ARB and ARG discharge into the environment.

A B S T R A C TClimate change has affected both water quantity and quality by increased rainfall, runoff, and associated pollutant loading in urban areas. Stormwater Best Management Practices (BMPs) are now being popularly considered for the reduction of increased runoff due to urbanization. Most research has been conducted on the analysis of BMP effectiveness under current conditions. However, there is no extensive literature on BMP effectiveness studies considering climate change. In this study, the effectiveness of BMP, porous pavement in particular, has been assessed under climate change scenarios. Climate change scenarios were generated by trend analysis of the historical rainfall data. The 2-year and 100-year design storms having 24-h durations were determined for three scenarios: current conditions, 2020, and 2050 using frequency analysis. Storm Water Management Model was then calibrated and used to evaluate the impact of climate change and the effect of incorporating porous pavement on runoff. Geographic information system analysis showed that 33.4% of the basin was suitable for the installation of porous pavement. Hydrologic modeling demonstrated that climate change can increase peak flows by as much as 26.9% relative to current condition. Further analysis showed that porous pavement can be effective in reducing the runoff volume and peak flow below current conditions for all scenarios, offsetting negative impact of climate change.

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