A novel framework for disinfection analysis in drinking water networks

Disinfection in drinking water distribution networks is essential to ensure water safety and potability. The primary cause of disinfectant decay is endogenous, mainly related to biofilm attached to or detached from pipe walls. While water utilities effectively monitor and manage water quality at the source, a more comprehensive framework is needed to understand disinfectant behaviour within the network. This study proposes a novel modelling framework based on a synthetic second-order kinetic model for analysing disinfectant consumption. The framework distinguishes between two endogenous reaction mechanisms: (i) reactions involving compounds detached from pipe walls and transported in the bulk flow, and (ii) reactions occurring locally at the pipe wall biofilm. The chemically based kinetic formulation highlights the roles of stoichiometry and reaction rate constants, which can be experimentally determined for specific water systems. The proposed framework supports water quality management by integrating monitoring data with hydraulic modelling. Its applicability was demonstrated on two real-world drinking water distribution networks managed by Acquedotto Pugliese S.p.A. in southern Italy: the small-scale Monteparano network and the large-scale Bari network. The results show that the framework effectively characterizes disinfectant decay mechanisms and provides actionable insights for asset management, from short-term operational control to long-term rehabilitation strategies.