resources - potable water

Question 1

what’s the difference between potable and pure water?

Answer 1

pure water:
- no dissolved substances at all

potable water:
- dissolved substances in small amounts

Question 2

what does drinking water need to have to make it safe to drink?

Answer 2

sufficiently low levels of dissolved salts such as sodium chloride. cannot have high eleven of microbes such as bacteria - this is potable water

Question 3

In the UK, what provides most of our potable water?

Answer 3

rain water as it contains low levels of dissolved of dissolved substances

Question 4

what is the production of potable water?

Answer 4

• rainwater collects in the ground in aquifers and in lakes, rivers and in reservoirs (good sources of fresh water)
• first, we choose a good source of fresh water (one of the above)
• pass water through filter beds to remove materials (leaves) and suspended particles
• water is sterilised to kill microbes. in the UK we use chlorine to sterilise potable water. in other parts of the world, ozone or ultraviolet light is used instead

Question 5

what does fresh water have?

Answer 5

low levels of dissolved minerals. in the UK we have access to a lot of this

Question 6

what is scarce in some countries? result of this?

Answer 6

fresh water so only available water may be too salty to drink (sea water). sea water contains very high levels of dissolved minerals. so in this case potable water, produced by desalination

Question 7

what is desalination?

Answer 7

it reduces the levels of dissolved minerals down to an acceptable level for potable water. one way to do this is using distillation or pass water through membranes called reverse osmosis. both processes require large amounts of energy making them expensive