Fig. 3.

SARS-CoV-2 N gene copies/L of raw influent wastewater stored at 4 °C, −20 °C, −80 °C for 7 and 14 days sampled from 6 different WWTP sites. A multi-factorial Three-Way Analysis of Variance was performed (balanced design, no interactions) on pooled data comparing the effects of WWTP, storage time, and storage temperature as independent variables and quantified viral RNA copy number as the dependent variable (n = 72). Statistical significance was set at α = 0.05. Error bars represent the standard error of the mean (SEM).