AWWA WQTC65714

Quantitative Microbiological Risk Analysis (QMRA) is a widely used method for predicting and assessing the risk of infection associated with microbial pathogens present in water. Its systematic application provides a scientific basis to assist risk management decision-making, allows ranking of intervention priorities and making sure that the system produces and delivers drinking water that meets health targets. The latest international guidelines on drinking water quality promote a preventive, integrated (from source to tap) framework for assessing and managing the safety of drinking water. The principal objective of this study was to develop a Monte Carlo model, based on the QMRA approach, in order to assess the relative risk of infection associated with the presence of Cryptosporidium and Giardia in drinking water. Specifically, this model analyzes the use of supervisory control and data acquisition (SCADA) data to integrate the reality of full-scale operations. The model developed allows: the assessment of the impact of the input models on the estimates of risk (parasite occurrence, treatment performance); the comparison of different treatment scenarios based on microbial risk reduction; and, the assessment of the impact of the ozonation and ultraviolet (UV) disinfection shutdown periods on the estimated risk. Includes 38 references, figures.