Intake and outfalls

Design and construction methodology for nearshore intakes and outfalls primarily for desalination, cooling water (for power generation including nuclear) and tailings disposal.

There is increased global interest in using seawater for industrial processes, mainly drinking water, mining use and energy generation. To do so requires developing seawater intake and effluent discharge works that are compatible with the surroundings and the industry operational processes. For an optimum design it is fundamental to have an adequate characterization of the marine environment and the functional needs of the process.

Apart from desalination, PRDW has designed intakes and outfalls for the power generation sector which typically involves seawater for cooling purposes. For example, a formative project in PRDW’s history was the marine infrastructure related to the cooling water for the Koeberg Nuclear Power Station near Cape Town, South Africa.

In addition, PRDW has experience of applications in the mining industry for the deep sea disposal of mining tailings.

HDPE pipe is the material used for many of these intake and outfall applications although steel has also been used within the range of PRDW projects.

PRDW has experience in the design of intakes and outfalls configured as submarine or elevated structures with syphon type operation. Currently, there are more than twenty systems designed by PRDW meeting the needs of various industrial processes in different parts of the world.

PRDW’s experience is not only in the hydraulic, structural and geotechnical design aspects, but also in the characterization of the marine environment in which these works are located. Additionally, PRDW has developed transient hydraulic models to evaluate the water level variations in intake basins and loading chambers in the event of abrupt operation intervention.

PRDW has the capabilities to develop a project from the earlier stages of engineering up to the detailing and construction assessment phases such as:

  • Selection and analysis of location alternatives
  • Design of effluent discharge systems using dilution and advection numerical models in near and far field
  • Hydraulic, structural and geotechnical design of intake and outfall systems
  • Construction methodology

In Chile, PRDW has been a pioneer in designing and adapting passive seawater intake systems for currently working structures. This is the case, for example, for the syphon intake of Santa María thermoelectrical powerplant in Coronel for which PRDW developed the structural design compatible with the requirements of the new system.

Technologies used by PRDW for the development of the intake and outfall projectinclude:

  • Numerical models of currents for the analysis of dilution and advection of effluents
  • Numerical models for the analysis of flow modification due to seawater intakes
  • Recirculation analysis
  • Structural analysis considering seismic and tsunami loadings
  • Physical models of energy dissipation and air entrainment control structures for outfall systems
  • Hydraulic transient model to verify operation of intake basin and discharge chamber and vacuum systems