Fig. 6.

Density. N = 3. Puro Virus was added to raw wastewater samples at a concentration of 5.1 × 10⁷ viral particles per sample. Raw samples were concentrated then added to a density gradient ranging from 0% to 28% iodixanol in a 0.25 M sucrose dilutant and spun in a Sorvall Discovery 100SE ultracentrifuge at 31,000 RPM for 3 h at 4 °C. RNA was extracted from fractions, and viral recovery was determined by qPCR.