Kinetic modelling approach as a decision support tool for chloraminated distribution systems

Disinfection and distribution system management of chloraminated systems can be a challenging task for water operators due to the complexity of chloramine chemistry. Formation of chloramines and maintenance of a suitable disinfection environment requires careful control of several operational parameters at the plant and at different locations along the distribution system. A mathematical model to simulate different disinfection conditions, based on chemical equilibrium and kinetic calculations, both at the point of chemical dosing and downstream in the distribution system, was developed. Common operational parameters for chloraminated systems, such as initial chemical dosages and the chlorine to ammonia ratio, were assessed. In addition, simulations of some selected operational strategies, such as breakpoint chlorination and dosing control strategies (feed-back and feed-forward) at a re-dosing station, were conducted and assessed. This modelling approach can be used as a decision support tool for water treatment operators to manage and maintain disinfection.