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2- Type of energy used in desalination, divided to :

a- Thermal energy (distillation).

b- Electrical energy(membrane).

RO

Membrane

EDR

Desalination
MSF

Thermal MED

VC

Figure 2.3 Energy used in desalination classification

2.2.1 Membrane Desalination

As mentioned in the previous section membrane desalination divided into RO
and EDR desalination.

1- Reverse Osmosis (RO) :Is the process of applying pressure on seawater and
passed it across a semi-permeable membrane, this caused the separation of
fresh water from salts like the osmosis process in nature, but the opposite.
Because of that, it is called Reverse Osmosis. To understand it better it is
necessary to first understand the Osmosis phenomenon. Osmosis is the process
of moving water from the low concentration region to the high concentration
region through a semi-permeable membrane naturally without any external
pressure[7].

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