A Safety Assessment for Consumers of Water Using Logical Trees

The lack of biochemical stability in drinking water increases the secondary contamination risk in water supply systems and hence represents a sanitary threat to consumers. The work presented here assesses the likelihood of such risk. The assessment is based on data obtained from one of the water treatment plants. The assessment of the bio-chemical instability risk combines both approaches: fault and event trees. Additional consideration was naturally given to the events that initiated the contamination at the outlet of the water treatment plant. It is concluded that if it is to protect the water-supply infrastructure representing a kind of critical infrastructure, a water-supply company needs to put more emphasis on the distribution of stable water in terms of its properties and composition, thus having no potentially corrosive properties. The assessment underlines the importance that water supply utilities should equally consider both the supplied water sanitary quality and the water supply service continuity.