AWWA ACE65562

Water quality of surface drinking water sources may vary considerably in time. These variations are associated mainly with variations of meteorological characteristics and diffuse and point-pollution sources in watersheds (Kistemann et al., 2002; Ott and Uhlenbrook, 2004). Water treatment plant operators must consider variations of source water quality to adequately adjust the treatment processes in plants. This is a considerable challenge, because raw water quality changes may occur very rapidly. When there is a delay between contamination occurrence and operator response, a possible deterioration of treated water quality could occur, increasing the risk to public health. In fact, for certain water quality indicators, in particular for microorganisms, the time delay between water sampling and laboratory analysis results is generally long (several hours and in general a day or more). Past research on modelling water quality in source waters has focused mainly on physico-chemical parameters such as color, conductivity and turbidity (Sun and Koch, 2001; Maier et al, 2004; Zhang et al., 2004). Much less attention has been paid to model microbiological parameters, such as coliforms. The objective of this research was to develop models to predict temporal variations of E. coli in a drinking water source. Models for E. coli prediction can be used as a tool for water utility operators for treatment adjustment in order to minimize the human risk of infection (as microbiological indicators are used as pathogen surrogates). Includes 6 references, figures.