Abstract: – Water resources in Kuwait are very scarce and do not meet the ever growing demand. To satisfy this colossal water demand and to compensate for the shortage of freshwater, the government has constructed desalination plants. Water desalination processes separate dissolved salts and other minerals from water from brackish, and seawater to produce water suitable for human consumption or irrigations. Reverse Osmosis (RO) is a proven technology for desalinating seawater; it is pressure driven membrane processes.

The analysis in this work enfolds an assessment of the performance of a small reverse osmosis plant with and without an energy recovery pelton wheel turbine. The data collected are from an experimental RO plant in the region; these data are concerned with the failures of several components and subsystems of the plant over a 4-year period of continuous operation. Using fault tree technique, the long term of the system is obtained by calculating the unavailability of the different subsystems. Since the plant is designed for continuous operation; the operational time was used to assess the performance of the plant