Facts & Figures
|Client||Systems Technologies for Environmental Protection|
|Location||Bukayriyah, Kingdom of Saudi Arabia|
|Post-treatment||Filtration, desalination and desinfection|
|In the media||sciencedirect.com|
About the RO pre-treatment with Crystalactor®
In the Al Qasim area in Saudi Arabia, several water treatment and supply systems were designed and built. All designs were virtually identical, based on a future population of 100,000 at a per capita consumption of 335 l/day, thus resulting in an average production capacity of 34,000 m3/d. All plants comprise softening, filtration, desalination and disinfection.
Taking into account the limited groundwater resources in Saudi Arabia, a requirement was that the plants should be able to operate at minimal losses (1% of the incoming flow). This could be achieved by selecting a softening process that produces a water free waste material, recovery of filter backwash water, desalination at a high recovery, and distillation of the desalination brine. Consequently, the designed water treatment system is more economical than conventional systems. The high recovery (99%) of the desalination installation could be achieved by preventing as much as possible the formation of calcium sulphate, by situating the softening stage upstream of desalination, and by recovery of water from brine through vapour compression distillation.
Crystalactor as solution towards Zero Liquid Discharge
The softening plant, with a capacity of 450 l/s, is based on softening using a mixture of caustic soda and soda ash, which is dosed to 6 softening reactors with a diameter of 1.85 m and a height of 7.6 m. The installation further comprises storage, mixing and dosing installations for caustic soda and soda ash and a seed sand storage and rinsing installation. After softening, carry-over filtration takes place.
Not all raw water is being softened: 150 l/s of groundwater is bypassed around the softening plant and filtered (mainly for removing iron) before being blended with 450 l/s softened water to arrive at the required total production of 600 l/s.The rapid sand filtration phase comprises 2 lines of 6 filters, treating both the softened water to remove carry-over and the raw ground water to remove iron.
The Role of Royal HaskoningDHV in the project
Royal HaskoningDHV carried out studies in the supply of drinking water in the Al Qasim area. Later, the company prepared tender documents for the construction of water supply and treatment systems for Al Khabra, Unayzah and Bukayriyah. For the Bukayriyah drinking water treatment facilities Royal HaskoningDHV assisted in the process engineering commissioning and start-up of particularly the softening plant, including carry-over filtration.