The Kingdom of Saudi Arabia is dependent on desalination of seawater to provide new
water supplies for the future. Desalination is expensive and it is very important to reduce
the cost and lower the energy consumption. Most seawater reverse osmosis facilities use
open-ocean intakes, which require extensive pre-treatment processes to remove
particulate and biological materials that cause operating problems. An alternative intake
is the subsurface system which utilizes the concept of riverbank filtration using wells or
galleries and provides natural filtration to improve the quality of feedwater before it
enters the desalination plant. This reduces operating cost and lowers energy consumption.
Research was focused on evaluating gallery-type intakes (beach and seabed galleries)
that could be used along the Northern Red Sea shoreline to provide a better quality
feedwater for desalination. The geological characteristics of the visited sites were
favorable for the development of seabed filter systems (offshore), but not for beach
gallery intakes. The low wave energy along the shoreline and the presence of mud or
rocky coasts made beach galleries infeasible. One of the potentially favorable sites for a
seabed filter was located in the nearshore area at King Abdullah Economic City (KAEC).
This site has a predominantly sandy offshore bottom with shallow water depths, and a
low tide range. In addition, the bottom is always covered with water and contains soft
limestone unit below the sand mantle that could be easy excavated to facilitate the construction of a seabed filter. About 50 sediment samples were collected from the site
and laboratory measurements were performed on them. Grain size distribution, porosity
and hydraulic conductivity measurements were performed on the sediment samples. In
addition, six statistical methods were used to estimate the hydraulic conductivity values.
Based on results of lab measurements, field observations, tide ranges and sediment types,
it is concluded that the geological conditions and characteristics of KAEC site are
feasible for design and construction of a seabed filtration system. A conservatively
designed cell with dimensions of 100 by 50 m would produce about 25,000 m3/day of
filtered seawater and seven cells could support a 60,000 m3/day (permeate) seawater RO plant.
|Date of Award||Mar 2012|
- Biological, Environmental Science and Engineering
|Supervisor||Thomas Missimer (Supervisor)|
- Beach Gallery
- Seabed gallery