11 october 2017


A desalination plant for a petrochemical complex.


External view of the plant featuring its Veolia Spidflow® DAF pretreatment system.

Located 20 km from the Gulf coast in the industrial city of Jubail, Saudi Arabia, the Sadara project is a large-scale petrochemical complex owned by a joint venture of Saudi Aramco and the Dow Chemical Company.
In order to meet the demand for high-quality industrial water of varying degrees of quality, the off-taker, Sadara Chemical Company, receives 148,800 m³/d (nominal capacity) and up to 178,560 m3/d (peak capacity) of desalinated water through a water supply agreement with the owner of the plant, Marafiq, the power and water utility company for the industrial cities of Jubail and Yanbu.
The plant is owned and operated by Marafiq on a 20-year build-own-operate (BOO) contract, and the engineering, procurement, construction, and commissioning (EPCC) contract, with the addition of 10 years of operation, was awarded to SIDEM in June 2013. The plant was completed in December 2016.
The Sadara Marafiq desalination plant delivers three different levels of permeate quality (for cooling tower make-up, demineralized process water, and utility water) and is designed to deliver a product water capacity ranging from 20 to 100% depending on water demand.
The plant has built-in redundancies to reliably maintain maximum production, and has a reduced footprint, thanks to the removal of intermediate tanks between the ultrafiltration pretreatment, the first reverse osmosis (RO) pass, and the second RO pass. Operation is optimized through an automated and remote-controlled system, which is also interfaced with the Sadara complex’s integrated fire and gas, process, and communication system.
Plant specifications
As the plant is located inland, it is supplied with seawater through Marafiq’s Cooling Seawater Supply network to Jubail. Seawater is drawn from the Arabian Gulf through dredged intake channels, passes through coarse trash screens and fine trash screens at the pump stations and is chlorinated before it is pumped into an open-air distribution channel and then with an intermediate  boosting station located several kilometers away feeding the plant with underground pipes.
The seawater supply and brine discharge piping infrastructure are pressurized and the plant has been designed with an intermediate seawater open air break tank with a dedicated pumping station for the pre-treatment lines, and with brine break tanks to enable a gravity flow up to the reject some 20 km away.
Brine is discharged through Marafiq’s return cooling seawater network which consists of another set of inverted siphons, on-shore discharge channels, the outfall, and a dredged discharge channel. Prior to the RO process, pretreatment consists of Veolia’s patented Spidflow® dissolved air flotation, self-cleaning strainers, and ultrafiltration. In order to achieve different quality levels and adhere to stringent quality limits year round, the plant consists of two passes of reverse osmosis, equipped with high-efficiency isobaric pressure exchanger energy recovery devices and fully automated flushing and cleaning-inplace systems to reduce energy consumption to around 4.35 kWh/m³, with the 1st and 2nd pass RO accounting for approximately 3.1 kWh/m³. Post-treatment consists of a clarified saturated lime water plant equipped with Veolia Multiflo® saturators, CO2 dosing, and disinfection by injection of chlorine gas, before storage in tanks dedicated to each product water quality.
Total capacity 148,800 m3/d
(Design capacity 178,560 m3/d)
Date awarded 2013
Date commissioned 2016
Feedwater TDS <45,000 mg/L
Product recovery 45% 1st Pass, 90 % 2nd Pass,
~37% total
Product quality <40 mg/L
(before remineralization)
Feedwater Temperature 15-38°C
RO Process description Two-pass
RO Operating pressure <71 bar
Intake Marafiq cooling seawater network
Concentrate disposal Marafiq cooling seawater return network
Number of trains 30 UF,11 1st Pass, 5 2nd Pass
Energy consumption 4.35 kWh/m3
ERD ERI, Isobaric PX
Membrane supplier Dow
Pretreatment Spidflow® DAF, straniers, UF
Post-treatment MultifloTM lime saturator, CO2, Cl2 gas
Storage  149,000 m3 of cooling tower make-up
Equipment supplier SIDEM (Veolia)
Procurement model BOO (20 years) between Sadara and Marafiq: EPC+10 years O&M contract between Marafiq and SIDEM
Offtaker Sadara Chemical Company (Dow/Aramco)

Power consumption breakdown at specific load (125,000 m3/d)


Power consumption Sadara