Surrogate and Pathogenic Virus Removal in Bench Scale Soil Aquifer Treatment
Loading...
Authors
Gearhart, Nicole
Issue Date
2023
Type
Thesis
Language
Keywords
Alternative Title
Abstract
The demonstration of enteric virus removal during indirect potable reuse is necessary to ensure safe water reclamation practices. This study aimed to evaluate the efficacy of soil treatment in reducing concentrations of Pepper Mild Mottle Virus (PMMoV), Hepatitis A (HAV), and Norovirus (NoV) gene markers through bench scale soil aquifer treatment with unsaturated soil columns. Three distinct infiltration rates (4.86 mm/hr, 9.35 mm/hr, and 14.0 mm/hr) were evaluated to determine their impact on the removal of surrogate plant virus PMMoV, and enteric viruses, HAV and NoV. The concentrations of viral markers in the column influent and effluent samples were measured through RNA extraction and then RT-qPCR, and the log reduction values (LRVs) were calculated to quantify the effectiveness of removal across the columns. The LRVs for PMMoV were 2.80 ± 0.36, 2.91 ± 0.48, and 2.72 ± 0.32 for infiltration rates of 4.86 mm/hr, 9.35 mm/hr, and 14.0 mm/hr, respectively. A one-way ANOVA indicated no statistically significant differences in LRVs among the various infiltration rates (p-value = 0.329). All HAV samples fell below the detection limit both in the influent and effluent. While NoV GI and GII markers were measurable in the soil column influent, and they were below the detection limit in the effluent. The use of half the Limit of Detection (LoD) for effluent values enabled the estimation of log removals, which were calculated as 1.42 ± 0.07, 1.64 ± 0.29, and 1.74 ± 0.18 for NoV GI and 1.14 ± 0.19, 1.58 ± 0.21, and 1.87 ± 0.41 for NoV GII at infiltration rates of 4.86 mm/hr, 9.35 mm/hr, and 14.0 mm/hr. This highlights the efficacy of soil treatment in reducing virus gene marker concentrations at various infiltration rates, and that spreading basins are an effective method for reducing the presence of viral contaminants in indirect potable reuse systems.