Probabilistic and credibilistic approaches to quantifying the risk of producing non-compliant water.

Summary In order to minimize the sanitary and financial risks due to the distribution of drinking water that does not comply with the legislation, it is necessary to define an efficient treatment process, without increasing the production cost. This thesis proposes an approach to help the design of a treatment system, based on the quantification of the risk of producing non-compliant water. In a first step, classical methods of operational safety (FMECA, Fault Trees,. . . ) are used to calculate the probability of non-conformity of the water at the plant outlet. This approach takes into account the quality of the raw water to be treated, the technical characteristics of the planned treatment process and the possible failures. In a second step, and in order to overcome the uncertainties and the lack of data of this model, the theory of belief functions is applied, and allows to define the degree of credibility in the respect of the legislation.