Abstract
The Minjur and Wasia deep fossil aquifers are the major source of water supply in the Riyadh region of Saudi Arabia. The water quality of both aquifers is rather poor with TDS ranging from less than 800 to more than 3000 pppm. Reverse osmosis treatment has been widely used in the region to desalt deep groundwater for potable and several non-potable uses. More than 100 privately owned small RO treatment plants with capacities ranging from 50 to more than 1000 m super(3)/day was identified in the region. A study has been conducted to assess the performance of 10 selected RO plants. The purpose of this paper is to identify and discuss the problems associated with the design, operation and maintenance of these plants.