COUPLING OF PV-POWERED RO BRACKISH-WATER DESALINATION PLANT WITH SOLAR-STILLS

Desalination of water is essential to supply sufficient good-quality w ater to remote areas to satisfy various needs. Saudi Arabia has enormo us amounts of deep water, and the underground water in many areas of t his country is so brackish that it requires extensive pre-treatment. I n order to utilize inland reserves of brackish water by the local inha bitants, the Energy Research Institute (ERI) of King Abdulaziz City fo r Science and Technology (KACST) installed a photovoltaic- (PV) powere d water desalination reverse osmosis (RO) plant in Riyadh, Saudi Arabi a. The reject brine rate from this plant is very high. Due to the inhe rent advantages of solar still assemblies, for instance; simple to con struct and maintain using locally available materials, and high techni cal feasibility in remote areas, a solar still plant capacity of 5.8 m (3) distillate per day is proposed to couple with the existing PV-RO p lant in order to utilize most of the reject brine instead of releasing it into the ground. The estimated cost of product water obtained thro ugh this design is found to be Saudi Riyal 1.9 (US$0.50) per m(3). The proposed design of the solar still assemblies can be applied to confi gure a 100% solar-powered desalination system for any location and qua lity of brackish water.