You should spend about 20 minutes on this task.
The diagram below shows how salt is removed from sea water to make it drinkable.
Summarize the information by selecting and reporting the main features and make comparisons where relevant.
Write at least 150 words.
The diagram illustrates the various stages in the desalination of seawater to make it suitable for drinking.
First of all, water is taken from the sea and then passed through a pre-treatment filter where the big impurities are removed. This backwash is then piped back into the sea through another filter. At the next stage in the process, the remaining water is forced through a membrane at high pressure and any impurities including salt are removed. After that, the seawater concentrate is returned to the sea while the remaining water goes through a post-treatment process. In this phase, the water is treated with lime, chlorine and fluoride to make it drinkable before it is stored in a reservoir. Finally, the desalinated water is distributed to the integrated water supply system for people to use as drinking water.
Desalination involves a process of purification of water followed by filtration and adding chemical agents. (153 words)
Grade: 7
Interest is maintained by the flexible use of input language, and a wide range of vocabulary and skilfully deployed grammatical structures. All stages are covered accurately, though some additions are made. The overview would work better as the second sentence.
