Cross-Regional and Seasonal Investigation of Somatic and F‑Specific Coliphage Log-Removal Credits in Six U.S. Wastewater Treatment Plants

Abstract Water demand necessitates innovative water management strategies, including wastewater reuse. However, the presence of viruses in reused water is a significant public health concern. This study investigated the potential of using somatic and F-specific coliphages as surrogates for routine monitoring during wastewater reclamation for reuse. Samples were collected from the primary influent, secondary effluent, and final effluent from six wastewater treatment plants across the United States. Analysis revealed geographic and seasonal variability in coliphage concentrations in the raw influents, with somatic coliphage ranging between 2.6 × 103 and 9.7 × 103 plaque forming unit (PFU)/mL and F-specific coliphage from 0.6 to 7.7 × 103 PFU/mL. From influent to effluent, 3.46 to 5.14 log virus removal (LVR) was observed for somatic coliphage, while F-specific coliphage removal ranged from 2.85 to 5.40 LVR. Most facilities showed a 4 or greater LVR of somatic coliphage from the influent to the final effluent. These findings support the inclusion of somatic coliphage for LVR monitoring since it was detected consistently in downstream processes. More research is needed to assess the ability of different unit operations in different climates to remove viruses during wastewater treatment.