Seawater desalination is a process using which
dissolved minerals including salts are removed from the seawater.
Despite water is a superabundant natural resource on the planet, but
still the available clean drinking water is just only 0.3 percent of the
world's total amount of water. The source of natural fresh water is
limited so sea water can play and is playing important role to meet the
drinking water demand. However, the sea water before can be used must be
treated (desalinated) which is not an easy task.
Seawater can be desalinated using various techniques and methods.
Distillation is a primary technique used for desalination. However, the
process is energy intensive. "One t" of drinking water is
obtained by using 620 kWh of evaporation enthalpy. In reverse osmosis on
the other hand the energy demand can be reduced to 7 kWh. Other method
that can be used is electrodialysis (ion exchange). Lot of factors
should be considered before choosing an appropriate technology.
Processes for Seawater Desalination
Sea water can be desalinated using following techniques:
Desalination Capacity Worldwide
The chart below gives the clear picture of worldwide desalination
capacity. As per chart MSF ( multistage flash) and Reverse Osmosis
accounts for 85% of total installed desalination capacities. Though both
thermal process (MSF,& MED) and membrane separation process are used
worldwide but now trend is shifting towards membrane separation process.
Desalination Capacity by Country
Following are the top five countries where maximum desalination plant
is located. It is clear that maximum plant is located in middle east as
there is maximum crisis of water. The maximum desalination capacity is
in Saudi Arabia followed by USA. Generally thermal process is followed
in these regions however now due to advancement in membrane technologies
they are too gaining popularity and their use is growing with a rapid
pace.
| Country |
Total Capacity (m/day) |
% of Global Production |
MSF |
MEE |
MVC |
RO |
ED |
| Saudi Arabia |
5,253,200 |
25.9 |
67.7 |
0.3 |
1.2 |
31 |
1.9 |
| United State |
3,092,500 |
15.2 |
1.7 |
1.8 |
4.5 |
78 |
11.4 |
| United Arab Emirates |
2,164,500 |
10.7 |
10.7 |
0.4 |
3.0 |
6.5 |
0.2 |
| Kuwait |
1,538,400 |
7.6 |
7.6 |
0.7 |
0.0 |
3.4 |
0.3 |
| Japan |
745,300 |
3.6 |
3.7 |
2.0 |
0.0 |
86.4 |
6.8 |
Related Resources
Case Study: Ashkelon Seawater Desalination Plant
Article
Seawater Desalination Giving New
Lease Of life To Middle East
External Resources
Techniques Of Desalination
