Comparing virus emissions from urine diverting and mix flush toilets

Flushing a toilet can emit and expose users to virus-laden droplets and aerosols. Virus emissions can differ between a mix flush and a urine diverting toilet which separates urine from feces. The separation of urine-associated and enteric viruses offers an opportunity to study these viruses and their different surrounding fluid environment. We developed a method to capture and compare emissions from flushing a urine diverting and a mix flush toilet. We used MS2 and T3 as surrogate viruses for enteric- and urine-associated viruses, respectively, and conducted experiments to evaluate how protein levels in the virus solution affect emissions. We found that toilet flushing can emit up to 1.22E+04 pfu MS2 and 1.41E+03 pfu T3 from the mix flush toilet and up to 1.46E+03 pfu MS2 and 1.80E+02 pfu T3 from the urine diverting toilet when 1010 pfu of MS2 and T3 were seeded into the toilets. Additionally, high protein levels in the virus solution increased virus emissions under certain conditions.