Marafiq Jizan SWRO Desalination Plant

Marafiq Jizan SWRO Desalination Plant

Operation and maintenance of SWRO Desalination plant and the drinking water distribution system in the Jizan industrial area (Jizan City for Primary and Downstream Industries – JCPDI).

Client is Power and Water Utility Company for Jubail and Yanbu (MARAFIQ) and the end user is Royal Commission for Jubail & Yanbu.

The plant has the capacity to produce 60,000 m3 of desalinated water per day, both for drinking and service water, which will be supplied to the industries installed in the JCPDI industrial hub. Its treatment processes include a dissolved air flotation system, seawater ultrafiltration, reverse osmosis modules and post-treatment to adapt the water to the use requirements. In addition, it has all the auxiliary equipment such as a dosage of reagents, an in-situ sodium hypochlorite production system, the corresponding pumping systems and a supply network to the entire industrial city.


Seawater desalination process is very energy intensive. We are committed to desalination sustainability by optimizing reverse osmosis plant to increase its efficiency and reduce the amount of energy used for desalination thus reducing the emissions and carbon footprint of desalination Plant. We have been using energy recover devices in order to minimize energy consumption.

Technologies and Solutions:

Seawater Intake System
Seawater Intake Pumps are provided to pump seawater from the Intake wet well to the desalination plant. Pre-chlorination/Shock chlorination is provided to prevent algal and microbial growth. Onsite Electro-chlorination system is used to produce sodium hypochlorite using sodium chloride brine.
Pre-treatment – Drum Screens
Intake Inlet Drum Screens are provided as a pretreatment to screen out floating debris.
Pre-treatment – DAF
Dissolved Air Flotation is provided as UF pretreatment to allow the plant to operate at full capacity during extreme inlet conditions such as algal bloom, storms and rough sea condition causing increase in turbidity.
Pre-treatment Chemicals
Sodium Hypochlorite for shock chlorination, sulfuric acid and Ferric Chloride for coagulation.

RO Section
Seven (6 working + 1 standby), two pass reverse osmosis system is provided to meet the required TDS quality and Boron level for drinking water.

Sodium Bisulfite and Antiscalant are dosed in the UF permeate prior to feeding it to downstream RO pass 1 units.

Caustic is dosed before BWRO system to raise the pH of feed water to optimum level to maximize the rejection of Boron and achieving its levels in permeate.

RO Pass 1 energy recovery system (PX units), to recover waste energy from SWRO concentrate, with booster pump and the associated piping.

Post-treatment (Remineralization)
The BWRO permeate is aggressive in nature. Therefore, remineralization is carried out by dosing lime solution along with carbonic acid solution in the BWRO permeate water to condition (remineralize) the desalinated water prior to final distribution and use.

Sodium hypochlorite is also dosed to maintain sanitary conditions in the potable water storage, transmission and distribution piping.

Potable Water Storage Tanks
Potable (remineralized) water is then transferred to the downstream Potable Water Storage Tanks.
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