ABSTRACT
As general requirements, USEPA (1 989) states that all public water systems, using any su$ace water or groundwater under the direct influence of sugace watel; must disinfect . . . disinfection must achieve at least a 99.9 and 99.99 percent inactivation of Giardia cysts and viruses, respectively. This must be demonstrated by the system meeting "CT" values in the rule ("CT" is the product of residual concentration (mg/Z) and contact time (minutes) measured at peak ho~rlyflow).'~
16.1 INTRODUCTION
T HE chemical or physical process used to control waterborne pathogenic organisms and prevent waterbome disease is called disinfection. The goal in proper disinfection in a water system is to destroy all disease-causing organisms. Disinfection should not be confused with sterilization. Sterilization is the complete killing of all living organisms. Waterworks operators disinfect by destroying organisms that might be dangerous, they do not attempt to sterilize water.
