Upgrading OF Tajura Seawater Reverse Osmosis Desalination Plant By Integrated Membrane Systems

الملخص

          The Tajura seawater reverse osmosis desalination plant commenced operation in 1984 with only 50% of its production capacity (10,000 m³/d). Feed water is supplied from an open intake located at Tajura on the Mediterranean coast and treated prior to RO using a conventional pretreatment system. As time passed, numerous obstacles brought down the plant’s production capacity to its lowest level. The operation problems with the coagulation-flocculation pretreatment system led to an increase in the silt density index (SDI₁₅) and fouling of the RO membrane. In addition, a non-continuous plant operation increased differential pressure, salt passage, and decreased water production through the membranes.

          This paper describes the problems encountered in the existing conventional pretreatment system and the conceptual Integrated Membrane System (IMS) design as a part of the plant rehabilitation process of the Tajura RO plant in Libya. The proposed design of the pretreatment system for the Tajura RO plant utilizes Hydranautics IMS technology. The IMS design is based on long experience from the operation of the two separate RO pilots with different pretreatment systems for a period of four months on the Mediterranean coast at Tajura city. The previously published data from those pilot plants confirmed the prior assumption that UF pretreatment produced stable feed water quality, measured by reduced turbidity and by the SDI15. The upgrading of the Tajura RO plant by IMS was designed for full product capacity (10,000 m³/day). The plant will employ dissolved air flotation pretreatment followed by Hydranautics IMS membrane technology consisting of four UF racks with Hydranautics HydraCap80, the overall UF plant is designed for a continuous UF to permeate flow of 670 m³/h. The nominal flux rate is 72.1 L/m²/h with all UF blocks in operation and downstream two seawater RO trains with SWC5 membranes working at 35% recovery