POLIOVIRUS-1 INACTIVATION AND INTERACTION WITH BIOFILM - A PILOT-SCALE STUDY

A pilot-scale study was initiated to examine the behavior of viruses p ulse injected into a distribution system. The influence of a free-chlo rine residual and that of virus preadsorption to clay particles was ev aluated by tracing the viruses both in the water flow and after elutio n from the biofilm. These experiments demonstrated, first, that virus preadsorption on 40 mg of Na-montmorillonite per liter increased the r esidence time of the viruses within the pilot plant by roughly three t imes and, second, that preadsorption to clay did not prevent viruses f rom being inactivated by chlorine, Moreover, with no clay added, a gre ater amount of viruses was recovered from the biofilm than from the wa ter flow (by a factor of 2 or 10 in the absence or presence of chlorin e, respectively), indicating a tendency for virus accumulation within biofilms.