Potable water Flashcards
1
Q
What is potable water?
A
Water with low enough concentration of salts and microbes that is safe to drink
2
Q
How do you make potable water out of fresh water?
A
- Filtering/screening (removing solids)
- Sterilise it, add small amounts of chlorine or UV + ozone (removes microbes)
- Add fluorides (for good dental health)
3
Q
What is the process called in which sea water is made into potable water?
A
Desalination
4
Q
What two methods can be used to desalinate sea water?
A
- Distillation
- Reverse osmosis
5
Q
How does distillation work to produce potable water?
A
- Heat sea water to evaporate pure water (as steam)
- cool and condense the pure water
- collect pure water (potable water in this case)
6
Q
What are the disadvantages of using distillation to make potable water?
A
- Difficult to dispose of waste water in a sustainable way
— Waste water is very salty, will harm marine ecosystems - Expensive
— requires a lot of energy (+ production of greenhouse gases)
7
Q
How does reverse osmosis work to produce potable water?
A
- Force sea water through semi-permeable membrane at a really high pressure
- The tiny pores allow water molecules to pass through and stops most ions and other molecules from passing through
8
Q
What are the disadvantages of using reverse osmosis to make potable water?
A
- Low efficiency —produces a large volume of waste water -Expensive —uses lots of energy (+production of greenhouse gases) —have to replace the expensive membranes
9
Q
What is desalination?
A
The production of potable water by removing salts
10
Q
What is pure water?
A
Water that contains no dissolved substances (no impurities)
