Enteric Virus Survival in Package Plants and the Upgrading of the Small Treatment Plants Using Ozone

Post-chlorinated effluent collected with a portable viral concentrator from four treatment plants in Jefferson County, Kentucky, yielded infective viral particles from three plants from spring through late fall. The pH, ,chlorine, turbidity, and coliform levels of these effluents indicated that viral persistence was correlated with inefficient processing which produced effluent environments that inhibited disinfection by chlorine. The disinfection potential of ozone was tested on secondary effluent and finished water seeded with poliovirus and Esaheriahia coli. Low doses of ozone inactivated viruses and bacteria in treated water, but not in effluent. The inactivation of bacteria by ozone does not appear to be caused by cell lysis. Inability of poliovirus to form plaques correlated with inhibition of capsid penetration. Electron micrographs revealed that ozone degrades capsids. Ozonation produced low levels of COD and TOC reduction in package plant effluent. Since the reaction rates were not a simple function of COD levels and ozone dose it would be difficult to standardize dose rates. The relative inefficiency of ozone in reduction of biological and non-biological pollutants in effluents, combined with its high cost, does not favor a recommendation for ozonation as a tack-on process to upgrade these plants