AWWA WQTC71645

This powerpoint presentation begins by providing a brief overview of research conducted at Ecole Polytechnique on conditions for intrusion with the goal of estimating public health risk from intrusion events. The microbial characterization of intrusion pathways is presented, along with modeling of transient pressure events. Conclusions for intrusion pathways in distribution systems indicate that: microbial indicators of fecal contamination have been detected in soil/groundwater/flooded vaults; frequency of detection is higher for flooded vaults than for soil/groundwater; when microorganisms are detected, the level of contamination in all pathways is similar to untreated river water; and, more studies are needed to assess pathogen concentrations in intrusion pathways. Conclusions for transient analysis for full-scale distribution systems indicate that: modeling transient negative pressure events in order to estimate potential intrusion volumes (to be ultimately used in a public health risk analysis) is not a straightforward process; and, field pressure data are necessary to validate model results. Includes figures.