Riyadh's reverse osmosis water treatment plants - the largest demineralization complex in the world

Abstract

The water demand in Riyadh has increased very rapidly during recent years owing to the rapid expansion of the city with a population growth of about 50,000 per year. The water from the main source, an aquifer of Minjur sandstone at a depth of 1,200–1,500 m reached, by drilling, has high hardness, sulphate and TDS. The existing water works with raw water cooling, lime-soda softening, sedimentation, filtration and disinfection have been in operation at Malez, Shemessy and Manfouha since 1969. VBB, a member of Swedish Consulting Group (SWECO), is consultant to the Ministry of Agriculture and Water (MAW) regarding the water supply in Riyadh. In 1973, VBB made an investigatory study on additional water treatment. The aims were to consider the possible need for further improvement of the actual water quality, to point out how such improvements could be achieved and finally, to discuss alternative treatment methods suitable for the purification of water taken from the new well fields. The purpose of this paper is to give an overview of the technical design and construction of the new water treatment plants in Riyadh, with a total capacity of about 254,000 m 3 /d. The treatment of Minjur deep-well water includes not only chemical softening but also demineralization with reverse osmosis (RO) as a final purification stage. The Salbukh plant (50,700 m 3/d) should come onstream in autumn 1979.