The diagram below shows how salt is removed from seawater to make it drinkable. Summarise the information by selecting and reporting the main features, and make comparisons where relevant.

The chart illustrates the process of removing salt from the seawater in order to make it drinkable, detailing each stage from drawing the

water

to supplying it to users.

Firstly

,

saltwater

Correct your spelling

salt water

show examples

is taken by a pretreatment filter using pipelines that link the sea with containers.

Subsequently

,

water

is filtered – part of it is put forward to another container

while

the filter backwash is again sent to the sea.

Then

, selected

water

is forced through a membrane at high pressure. Since

water

molecules are smaller than salt ones, they are capable of going through the membrane. Salt,

in contrast

, in the form of the seawater concentrate is forced to return to the sea. Before drinkable

water

can be stored it has to undergo a process of chemical supplementation, which is called post-treatment.

Such

a process is responsible for cleaning the

water

using lime, chlorine, and fluoride. Clean

water

is

then

stored waiting to be sent to users. It happens through the integrated

water

supply system, which links

water

storage and recipients.