Reconciling ‘actual’ risk with ‘perceived’ risk for distributed water quality: a QFD-based approach

This paper explores the application of the quality function deployment (QFD) approach to identify and prioritize factors to reconcile ‘actual’ risk with ‘perceived’ risk for drinking water in a distribution network. Consumers' complaints (regarding water odour, taste, colour and other problems) and consumers' perception about water safety are used to define customers' requirements (aka ‘whats’). Twelve water quality parameters and distribution network properties (e.g. turbidity, pipe breaks) are used as indicators for drinking water quality – the product characteristics (aka ‘hows’). Correlations between ‘whats’ and ‘hows’ are established using data obtained from a case study. Opinions of experts in drinking water and consumers are used to define correlations between the ‘what’ ‘microbial safety’ and the ‘hows’. The analytic hierarchy process allows prioritizing customer requirements. Three QFD-based methods are applied to prioritize factors affecting water quality in a distribution network. The proposed approach is demonstrated through a case study of a water distribution network in Quebec City (Canada). Results show that the factors that primarily affect customers' requirements include free residual chlorine, turbidity and trihalomethanes. Sensitivity analyses using three scenarios confirm the robustness of the proposed approach. Utility managers must take action, especially concerning these product characteristics, to satisfy customers' requirements.