Comparative survival of enteric viruses and coliphage on sewage irrigated grass

The fate of coliphage and human enteric viruses on turf grass was studied in order to elucidate the potential risk to public health when grass is irrigated with activated sludge treated sewage effluent. The survival of seeded collphage MS-2, poliovirus type 1, and rotavirus SA-11 was studied outdoors during winter and summer. Virus inactivation rates were influenced by temperature as well as by type of virus. Coliphage, poliovirus, and rotavirus average inactivation rates (K = log inactivated/hr) were 0.17, 0.06 and 0.10 per hour, respectively, during the winter (4-10°C). In contrast, during the summer (36-41°C) K = 0.45, 0.37 and 0.20 per hour for MS-2, poliovirus, and rotavirus, respectively. To achieve a 99% (2 log₁₀) virus inactivation on turf grasses after the application of sewage effluents, 8 to 10 hours would be needed during the summer and 16 to 24 hours would be needed during the winter. and 0.10 per hour, respectively, during the winter (4-10°C). In contrast, during the summer (36-41°C) K = 0.45, 0.37 and 0.20 per hour for MS-2, poliovirus, and rotavirus, respectively. To achieve a 99% (2 log₁₀) virus inactivation on turf grasses after the application of sewage effluents, 8 to 10 hours would be needed during the summer and 16 to 24 hours would be needed during the winter.