Enteric virus and pharmaceutical and personal care product attenuation in a bench-scale ozone-soil aquifer treatment...

Ozone-soil aquifer treatment (O₃-SAT) could be employed in land-based treatment systems to achieve improved pharmaceutical and personal care products (PPCPs) and pathogen reduction prior to de-facto recharge of aquifers with reclaimed water. A bench-scale demonstration of O₃-SAT was investigated utilizing denitrified effluent to assess attenuation of PPCPs, norovirus (NoV), pepper mild mottle virus (PMMoV), bacteriophage MS2, and tomato brown rugose fruit virus (ToBRFV). Ammonification followed by nitrification evidenced the role of microbial degradation in contaminant removal in the soil columns studied. Ozonation was effective for NoV genetic marker oxidation to below detection (> 4 log removal values), while the PPCPs were removed in the soil columns. Indicator viruses demonstrated limited (ToBRFV and MS2) to negligible (PMMoV) oxidation during ozonation; thus, attenuation via microbial degradation and sorption mechanisms during soil treatment was the governing factor for achieving ∼2 log removal values across treatment conditions. PPCP removal efficiency was compound dependent but followed the categories: 1. Effective oxidation and attenuation, 2. Moderate oxidation and attenuation, 3. Recalcitrant to oxidation and attenuation. Ozonation of characteristically recalcitrant compounds such as sulfamethoxazole, meprobamate, N-N-diethyl-m-toluamide and primidone increased the collective O₃-SAT removal compared with SAT alone. Desorption of carbamazepine previously adsorbed to below detection was observed, driven by historical concentrations in soil or modifications to the concentration gradient. These results highlight O₃-SAT as a promising enhancement for improving robustness of water reuse treatment systems under a range of operational scenarios.