ACWA Emirates has produced first water from a new, highly-efficient reverse osmosis system that will provide water for irrigation and drinking at Riyadh’s Princess Noura Bint AbdulRahman University for Women (PNUFW).

The university’s vast expanse of landscaping generates a requirement for 13,000m3/day of irrigation water, which is being provided via a mix of treated wastewater, filtered groundwater and desalinated water.

PNUFW is the largest women’s university in the world, and one of the ten largest of any kind. The campus now spreads over eight million square metres, and the fast-track expansion was undertaken in just two years. The project has a strong focus on sustainability, in which water efficiency plays a key role, and the university is targeting LEED (Leadership in Energy and Environmental Design) certification for the entire campus.

ACWA’s client, the CCC-El Seif joint venture, required a bespoke solution for the campus’ significant irrigation needs. Initially, ACWA looked at all available water resources, including the treated wastewater and the deep well saline water. The Company then proposed the most feasible and reliable management processes to achieve the required solution in terms of both quality and quantity. ACWA sourced best-in-class solutions from blue-chip equipment providers around the world to minimise the risk of shutdown and provide the longest possible lifetime. Quality is paramount: the system will have multiple redundancy and a very high level of automation.

At the heart of the solution is an RO desalination plant to treat water from two 1700m deep wells that will access the deep, brackish aquifer beneath the city and provide a maximum daily output of 9600m3/day.

Groundwater arrives at the surface at 60ºC, so temperature control is necessary ahead of treatment, which is achieved using two cooling towers that reduce the water temperature to 33ºC.

Initially, the water passes through a mixed-media filter bed to remove any significant particulate matter, and then undergoes several stages of RO treatment. An optimal multi-stage process is being used to maximise the efficiency of treated water recovery and minimise reject water.

The RO system is capable of producing 5285m3/day of desalinated water at full capacity, and will be blended with filtered raw groundwater to produce 7045m3/day of water. This will be blended in an irrigation tank with treated wastewater from the adjacent MBR wastewater treatment plant to provide the required total of 13,000m3/day.

ACWA’s contract has also involved providing the specialised submersible pump stations required to abstract the hot water from the two deep wells, as well as the cooling towers and all process and M&E instrumentation. The company is also providing the PLC system that controls the irrigation flows and blending process, which will keep the final water quality to a stringent TDS of below 800ppm.

Although work on this project only began in March, water was produced in mid-June from the first RO stream. The other RO stream is currently being commissioned which will bring the plant to its full design capacity.

ACWA Emirates managing director Gary Jackson said:

‘The company is delighted that the RO system has produced first water –this complex, fast-track project has involved considerable flexibility and close liaison with many different project stakeholders. Our commitment has been to provide the best possible solution to meet the site’s ambitious sustainability requirements.’

Further information:

ACWA Emirates LLC. +971 (0) 4 3821 900

www.acwa.co.uk

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