Development and Use of Distribution System Models for Improving the Security of Drinking Water System

摘要

Guidance was developed for water system distribution software application to security related uses. This guidance was broken into four uses: model development, pre-scenario analysis, post-scenario analysis, and detector placement analysis. This guidance allows a water utility to take a water modeling program, develop it, and then analyze how water systems will respond to different water security scenarios. This will help the utility determinate areas of vulnerability. This guidance will also allow the utility to evaluate the siting of detectors. Additionally, it will also allow analysis of post-scenario responses to determine the travel of any contaminant that may have been introduced into the system. The detectability of Cryptosporidium parvum was then analyzed using normally water quality parameters, including turbidity, total organic carbon, pH, chlorine residual, and conductivity. The detection levels for this contaminant was then calculated, which was based on a statistically significant change in these parameters. This statistically significant change was the 3-sigma value. C,yptosporidium parvum was analyzed in the model using the modeling guidance with four different scenarios that were developed to determine the influence of feed methodology and location. The assumptions of the amount of Cryptosporidium parvum that could potentially be available were determined from the literature review. The results of the modeling showed that the Cryptosporidium parvum would be capable of producing widespread system contamination. This type of contamination would not likely produce a large number of fatalities, but there would be widespread illnesses caused throughout the system. It was found that contamination efficacy is dependent more on location of the backflow rather than the pumping method. The detection methods evaluated would detect the contaminant, but at concentrations much greater than the infective dose.