Availability assessment of a reverse osmosis plant: Comparison between Reliability Block Diagram and Fault Tree Analysis Methods Original Research Article

Today, the reverse osmosis (RO) becomes a process of first importance for fresh water production worldwide. For this reason, downtimes due to repairing operations (following breakdowns, blockage of membrane, pressure losses, etc.) or preventive maintenance (cleaning of membranes, changes in components, etc.) have to be minimized in duration and frequency to ensure maximum availability. Indeed, improving the availability (or the reliability) of the RO plant as a whole system, objectively leads to a substantial reduction in operating costs and maintenance. In this paper we consider two methods for availability and effectiveness assessment of an RO unit, where the main objective is economic optimization. The two methods are Reliability Block Diagram Method (RBD) and Fault Tree Analysis Method (FTA). For the validation of both methods, we used data related to an RO unit operating in Kuwait and corresponding to four years operation. A comparison between both methods was performed in order to highlight the efficiency and the limitation of each one.