Seawater intake system in Test Bed seawater reverse osmosis (SWRO) project

ABSTRACT

The Test Bed for seawater reverse osmosis desalination plant having a capacity of 10 million imperial gallons per day, located in Gijang-Gun, Busan, South Korea, is under construction by Doosan Heavy Industries and Construction. Generally, beach well-type intake system furnishes a good seawater quality, but the amount of water which can be extracted from each well is limited by the geological formation surrounding the wells. In case of the Test Bed, unfortunately, beach well-type intake could not be adopted, therefore, in order to achieve a similar level of seawater quality, as being able to get by adopting the beach well intake, the Test Bed intake system is directly connected with a newly developed dissolved air flotation with ball filtration system. The Test Bed intake system consists of passive offshore screen, intake pipe, and air-burst cleaning system. In order to avoid possible clogging of the offshore screen by oceanic substances, compressed air-bursting system is installed onshore. In addition, underground tunnel is adopted to minimize the environmental impact during construction. Also, to avoid possible brine recirculation, a simulation study on the recirculation of brine discharge was carried out. The simulation study has been conducted using Environmental Fluid Dynamics Code model which is a three-dimensional hydrodynamic and water quality model. Grid generation is arranged 11.5 km horizontally and 15.5 km vertically. Mesh is varied from 20 to 200 m with 10 layers. Using tidal current and tide data of Korea hydrographic and oceanographic administration (KHOA), this model was verified. The result shows that if the distance between intake and outfall is 50 m, brine is induced to intake and excessive salinity at intake increases to 800 ppm in summer. If the distance between intake and outfall is increased to 70 m, the resulting maximum excessive salinity is 340 ppm. Finally, the outfall is displaced 70 m from intake.

Keywords:

• Test bed
• Seawater reverse osmosis (SWRO)
• Desalination
• Intake
• EFDC
• Brine
• Recirculation
• Offshore screen

Acknowledgments

This research was supported by a grant (07SeaheroB03-01) from Plant Technology Advancement Program funded by the Ministry of Construction & Transportation of Korean government.

Notes

Presented at The Fifth Desalination Workshop (IDW 2012), October 28–31, 2012, Jeju, Korea