Veolia Water Systems Westgarth, a global expert in the supply of water treatment process plants, played a major role in the successful implementation of the Kindasa expansion project.

The company claims to be the largest single supplier/operator of sulphate reduction membrane systems, and with its recent purchase by Veolia Water Solutions and Technologies is now able to utilise the specialist R&D and process abilities of the world’s largest water treatment company.
The Kindasa Phase B1 sea water reverse osmosis (SWRO) desalination plant was designed by VWS Westgarth.
 “The Kindasa SWRO plant is the first project of its size to use a membrane Ultrafiltration system-based pretreatment upstream of the seawater reverse osmosis (SWRO) plant,” says a VWS Westgarth spokesman. “The direct barrier provided by the ultrafiltration membranes ensures consistent product quality, irrespective of raw water conditions.”
Kindasa Phase B1 plant is the first of its size that uses a membrane filtration-based  pre-treatment prior to the SWRO membranes. The plant is located in Jeddah Islamic Port (JIP) on the Red Sea coast of Saudi Arabia.
Giving an overview of the project, the spokesman says the deteriorating seawater quality in the seaport together with seasonal algae bloom and frequent ship movements created very difficult conditions for operation of the conventional pre-treatment, which was confirmed during the operation of the existing Phase A SWRO desalination plant built in 1999 within the JIP area. 
“As a result of such experience, a series of extensive pilot trials were conducted in 2002 – 2003 in JIP using a hybrid pre-treatment system comprising both dual media and ultra filtration membrane,” the spokesman says.  “The results of the pilot tests confirmed that a combination of both filtration systems would provide the best quality water feeding the SWRO membranes.  Despite the higher capital cost of the hybrid pre-treatment, this option minimises SWRO membranes fouling resulting in less frequent chemical cleans and increased plant availability.”
The Kindasa Phase B1 SWRO desalination plant consists of the following treatment systems and equipment:

• Seawater Intake: The existing intake structure was refurbished and equipped with new penstocks, bar screens and travelling band screens. The intake pipe, which connects JIP’s berth and intake structure, was cleaned of scaling and marine growth in order to minimise head loss and provide enough flow capacity for both, Phase A and Phase B plants.
• Dual Media Filtration: Five off horizontal, single-chamber dual-media filters (DMF) were installed to provide coarse filtration prior to the next filtration stage. Each DMF has a diameter of 3.3 m and length of 10 m. Filter media comprises 600 mm of silica sand (0.4 – 0.8 mm) and 800 mm of pumice (1 – 1.5 mm). Filters operate at a normal filtration velocity of 16 m/h with a maximum of 20 m/h when one DMF vessel is in backwash. The filtration cycle is set to 24 hours, but pilot test results show that a cycle length of up to 48 hours is possible. At the end of the filtration cycle, the filters are backwashed with air and water. Provision for coagulant (ferric chloride) dosing is provided to enhance filtration efficiency during periods of poor seawater quality.
• Automatic self-cleaning strainers: Four off strainers with a mesh size of 100 microns are installed downstream of DMFs to provide protection of UF membranes against any sharp particles (like sand carryover from DMFs).
• Ultra Filtration (UF): Eight off UF blocks are installed prior to the SWRO trains to provide best feed water quality for RO membranes.  Each UF block consists of 88 hollow fibre ultra-filtration membrane vessels. The system is designed to operate with one UF block always in backflush and one under chemical clean or maintenance if necessary.  The backflush and chemical cleaning system is provided for the UF plant to maintain its performance and availability.
• Reverse Osmosis Plant: Three off RO trains are provided, each to produce 372.8 cu m/h of permeate. Each RO train comprises two passes, one seawater and one brackish water. Each RO pass has two brine stage configuration. The first RO pass contains 87 pressure vessels in first stage and 60 pressure vessels in the second stage. Each pressure vessel is equipped with six off Hydranautics SWC3 SWRO membranes. An inter-stage booster pump is installed between stages to increase pass recovery to 50 per cent.  The second RO pass contains 28 pressure vessels in the first stage and 10 pressure vessels in the second stage. Each vessel is equipped with six off Hydranautics ESPA2 BWRO membranes. The second RO pass is designed for operation at 90 per cent recovery, with all reject stream returned back to first RO pass feed.  To minimise the plant energy consumption, each first RO pass high-pressure pump motor is equipped with a VFD (variable frequency drive) and the energy recovery turbine is connected to each first RO pass high pressure pump. Overall designed plant energy consumption is 5.48 kWh/m3 of permeate.
• Chemical dosing system: Seven different dosing units required to condition both the raw feed and the product water.
• Neutralisation system: The waste water produced by UF backflushes and chemical cleans on UF and RO is neutralised in Neutralisation System and then disposed to site outfall, thus minimising plant impact on marine life at plant outfall area.
The engineering and construction challenges were tough. However, all of them were successfully resolved through a close working relationship of all the contracted parties, says the spokesman.
He explains that the following process and construction challenges had to be dealt with during the design and construction phase of the Kindasa
Phase B1 SWRO Desalination Plant:

• Utilising the existing intake facility consisting of 242 m long intake pipe of l meter internal diameter with 25 years of marine deposits creating a flow restriction;
• Upgrading the existing 25-year-old intake structure and modifying it to suit the positioning of the Phase B equipment along with Phase A seawater pumps in the restricted space;
• Keeping the Phase A plant in operation while refurbishment of the intake structure and other Phase-B integration works were carried out;
• Utilising the existing outfall facilities with the available gravity flow head and redesigning it to handle large transient flows associated with the operation of the Phase B plant;
• Integration of Ultra Filtration (UF) system with a conventional filtration system (DMFs) to improve the feed water quality and optimising their sizes to minimise the pre-treatment system cost;
• Site space limitation posing problem to design efficient plant layout and material storage during construction.
The company has provided three major forms of desalination technologies — Multi stage flash (MSF), Multi Effect Distillation (MED) and Reverse Osmosis ( RO) – to many projects in the region.