EARLY WARNING OF FAECAL CONTAMINATION OF WATER : A DUAL MODE, AUTOMATED SYSTEM FOR HIGH -(<1 hour) AND LOW-LEVELS(6?11 hours)

The objective of the present work was to use the automated Colifast technology for establishing and testing dual model for estimating the level of faecal contamination of water sample : a rapid format based on initial measurement of beta-galactosidase activity and a presence-absence format base on verifying beta-galactosidase induction by coliforms growing in the selective medium. the purpose for both modes, was to provide a simple, rapid and robust tool for the user, such as a water treatment plant operator, to supplement microbiological information to other physical and chemical monitors and make operational decisions.