12


WATER ENGINEERING 12.1 Vocabulary linking ideas • referring back distilled A Look at the spidergram on the right.


1 Match each source of water with a definition on the opposite page.


2 Mark each source on the diagram as natural (N), processed (P) or both (N/P).


B Study the words in box a. 1 What part of speech is each word?


2 Copy and complete the table with other forms for each word.


3 Group the words according to their stress pattern. 4 What is each word’s connection with water?


Noun acidity, acid, Adjective acidic, acid


C Read the WEA text on the opposite page. 1 What type of text is it?


2 Check the meanings of any unfamiliar words.


3 Look at the highlighted words. Connect each word or phrase to a noun or idea it refers back to.


Example: the book refers to the previously mentioned text


D Read the text on the right. 1 What part of speech is each blue word?


2 Find synonyms for the blue words. Use a dictionary if necessary.


3 What is the function of the red words and phrases?


E Look at Figure 1 on the opposite page. 1 What does the chart show?


2 What does the percentage of frozen water represent?


3 Which text from Exercises C and D does the chart illustrate?


F Study the verbs in box b. What are the noun forms?


G Look at Figure 2 on the opposite page. 1 What does the diagram show? 2 Discuss the process in pairs. Use any verbs from box b.


3 Write a short paragraph, using ideas from your discussion. Use the passive form of verbs where appropriate.


94 Verb World water demand


In many parts of the world, water scarcity is a critical issue and demand already exceeds supply. There are many contributing factors to demand growth. These factors include the continuing increase in population and urbanization, rapidly growing economies, such as India and China, more water-intensive agriculture, and the various negative effects of climate change. The supply of freshwater, however, does not grow: less than 3% of the world’s water is fresh, most of which is in the form of ice. The sharp growth in demand means that in certain water-stressed regions, desalination is the only effective way of providing enough freshwater for domestic, agricultural and industrial uses.


The desalination process removes salt and other dissolved minerals from seawater, brackish water or recycled wastewater. According to the International Desalination Association, there are currently more than 15,000 desalination plants in operation worldwide, the largest of which has a capacity to produce more than 900,000 m3


potable


brackish saline


fresh a water surface


acidic alkaline chlorination corrosive disinfect distillation evaporate filtration impurity irrigation organic oxide permeable porous toxic


ground


desalinated waste


of water per day. That


is enough to provide, say, domestic water to a very large city. Around 50% of these facilities are located in the oil-rich Middle East, in places where freshwater is scarce, but where energy – for the moment – is plentiful.


b condense discharge


dispose of heat produce pump separate treat


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