Aerosolization of Ebola Virus Surrogates in Wastewater Systems.

Recent studies have shown that Ebola virus can persist in wastewater. We evaluated the potential for Ebola virus surrogates to be aerosolized from three types of wastewater systems: toilets, a lab-scale model of an aeration basin, and a lab-scale model of converging sewer pipes. We measured the aerosol size distribution generated by each system, spiked Ebola virus surrogates (MS2 and Phi6) into each system, and determined the emission rate of viruses into the air. The number of aerosols released ranged from 105 to 107 per flush from the toilets or per minute from the lab-scale models, and the total volume of aerosols generated by these systems was ∼10-9 to 10-7 mL per flush or per minute in all cases. MS2 and Phi6, spiked into toilets at an initial concentration of 107 plaque-forming units per milliliter (PFU mL-1), were not detected in air after flushing. Airborne concentrations of MS2 and Phi6 were ∼20 PFU L-1 and ∼0.1 PFU L-1, respectively, in the chambers enclosing the aeration basin and sewer models. The corresponding emission rates of MS2 and Phi6 were 547 PFU min-1 and 3.8 PFU min-1, respectively, for the aeration basin and 79 PFU min-1 and 0.3 PFU min-1 for the sewer pipes.