Long-term availability modelling of water treatment plants

Water treatment plants (WTPs) are characterised as complex configurations of repairable and deteriorating components. Previous studies have mainly focused on the average or steady-state availability of such systems while ignoring inherent characteristics like degradation. The current research proposes a two-level hierarchical model for long-term availability analysis of WTPs. To do so, at the component level, a condition-based technique (semi-Markov) or a failure-based technique (non-homogeneous Poisson process) is proposed based on the type and amount of available data while at the system level a reliability block diagram can be used to combine the component-level availabilities. The application of the methodology has been demonstrated on a real case study in the Netherlands.