Multi-Criteria Evaluation of the Vulnerability of the Urban Water Supply Network Against Biological Attacks

The water supply network is one of the most critical infrastructures of human societies, which could cause illness or death in many consumers due to its expanding nature. Water pollution is one of the ways of spreading biological pollutants among the population, which is known as bioterrorism today. Biological contamination usually occurs with the use of pathogens and biotoxins. Therefore, recognizing the vulnerable stages of the water supply network against various pollutants is of particular importance. In this research, in the first stage, a selection of five pathogens (Bacillus anthracis, Cryptosporidiosis, Francisella tularensis, Vibrio cholerae, Shigella) that are more likely to pollute water sources have been made. Thus, employing each component of the water supply system (including raw water source (dam)), Raw water storage tank, water treatment plant, treated water transmission line, treated water tanks, and distribution network (30 scenarios) were defined. In the next step, using multi-criteria group decision-making and employing three main criteria (vulnerability of each water supply stage, the amount of contaminant damage power, the amount of contaminant risk in each of the water supply stages) and their sub-criteria, the weight of each criterion was determined from the perspective of decision-makers by utilizing GFDM software. After analyzing the scenarios, the risk level of each scenario was ranked. Scenario 26 created the most risk, which consists of introducing the pathogen Bacillus anthracis into the distribution network. The entry of contamination into the distribution network due to high availability and lack of subsequent treatment steps, as well as the slight chance of preventing the contaminant from reaching consumers, can cause many diseases and deaths. Furthermore, it has a high resistance against chloride and is stable in water, so the entry of this contaminant into the distribution network can be dangerous. Considering the existing conditions, recognizing and calculating the risk of different scenarios can lead to readiness and increase the speed of action in response to possible biological attacks.