Wastewater desalination in Israel

Desalination of secondary effluents in Israel by use of advanced IMS technology has been considered as a major water supply option since different IMS technologies evolved in the last several years for a variety of desalination applications like desalination of brackish surface, seawater and the more challenging - secondary wastewater. A comprehensive research work on advanced wastewater treatment at the Shafdan's WWPT [Mekorot reclaims about 68% of Israel's reused effluents for agriculture (190 out of 280 million cu.m./year) in several facilities, among which is the Shafdan-Dan Region Reclamation Plant - the largest of its type in the world], has been performed since 2000, when Mekorot started operating a pilot plant at this site. In the current research an innovative Zenon's UF membrane (ZeeWeed(R)) performance is being evaluated. The wastewater reclamation experimental work aims at reaching two critical water quality objectives, COD and salinity, in a way that RO may be applied only to a part of the flow or even may not be required at all. The pilot scale investigations included operation of two UF technologies: encased and immersed, low fouling RO membranes, different types of antiscalants at different UF and RO operational parameters, such as flux, recovery, UF backwash and disinfection processing. The main objectives of the pilot studies are validation of the performance data specified by the system suppliers and optimization of the operating parameters to achieve the possible lowest cost. A general overview of Mekorot's pilot studies is presented in the paper, including important results such as the data of operation at high recovery of up to 90% in presence of high organic loads and cost assessment of wastewater desalination in comparison with seawater desalination.