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The Saline Water Conversion Corporation (SWCC) is responsible for desalting seawater and faces several challenges, such as high feed salinity with high feed temperature and very stringent permeate quality standards (TDS < 50 mg/l, chloride <25 mg/l, and boron < 2.4 mg/l). Most plants employ hollow fiber membrane technology, with smaller plants operating at 30–35% recovery rates, whereas larger plants operate at an approximately 42% recovery rate. The SWRO permeate boron concentration is between 2 and 3 mg/l. Finally, the Umm Lujj SWRO plant employs NF pretreatment and operates at approximately 32.5% overall recovery. This study focuses on designing high recovery SWRO operations by employing spiral wound membranes and recent design approaches. The study using Gulf seawater includes a performance comparison of five different SWRO elements, an examination of the performance of conventional 6-element arrays compared to 7- and 8-element arrays, a performance comparison of 5 hybrid and non-hybrid SWRO designs and an evaluation of the performance of two hybrid SWRO designs operated at 46.5 and 48% recovery and incorporating a split partial two pass approach over 6100 hours of operation. The results indicate that spiral wound membranes with recent design approaches succeed in maximizing the overall recovery up to 45–46.5% compared with existing plants, with an overall recovery of 33–38%. [ABSTRACT FROM AUTHOR]

For providing advanced desalination the combination of the improvement of water recovery ratio in the reverse osmosis (RO) process and the No-Chlorine/No-Sodium Bisulfite (SBS) Dosing process was studied. In order to prevent membrane fouling even in high recovery water operations, an advanced two-stage design was implemented to (1) control the permeate flux through the RO membrane module, (2) optimize the system to reduce contaminant build-up and (3) eliminate the use of chlorine and SBS, which can accelerate membrane fouling. The system was evaluated by monitoring the biofouling and the microorganisms proliferation on the membrane surface based on membrane biofilm formation rate (mBFR). The pilot plant was operated in the condition of a water recovery rate of 55%. As a result, the system was operated for longer than four months without membrane cleaning (clean in place; CIP) and the possibility of operation for seven months without CIP was confirmed by the extrapolation of the pressure values. In addition, the mBFR is a reliable tool for water quality assessment, based on a comparison between the fouling tendency estimated from the mBFR and the actual membrane surface condition from autopsy study and the effectiveness No-Chlorine/No-SBS Dosing process was verified from mBFR of pretreated seawater. [ABSTRACT FROM AUTHOR]