Purifying Water Flashcards
Explain the process of water purification.
Screening process
Settlement tank
Aluminium sulfate is added to coagulate dirt particles
Filtration
Chlorine added
Fluorine added
What does screening do?
Removes twigs and leaves
What does the settlement process do?
It allows all of the sand and soil to settle in the bottom of the tank, roving it from the process.
What does adding aluminium sulfate achieve?
It allows the smaller dirt particles to coagulate and sink to the bottom of the tank.
What does filtration do?
The water is run through fine sand to filter remaining impurities.
What does adding chlorine do?
It kills the bacteria and makes the water drinking water.
Why is fluorine sometimes added to the water once purified?
To harden the population’s teeth
What are the arguments for the addition of fluorine?
It benefits your health- it hardens your teeth.
It is only added in tiny amounts.
What are the arguments against the addition of fluorine to the water?
It is unethical as you are not given a choice about it.
It can increase chances of learning difficulties.
What are the further filters sometimes added to water in the home?
Carbon filter added to remove chlorine and possibly other impurities.
Silver particles discourage growth of bacteria.
Ion exchange resin soften water.
What is the purpose of the settlement tank?
Allows the sand and soil to settle, removing them from the process
What is the purpose of the ion exchange resin?
> it is a polymer designed to remove:
- calcium
- magnesium
- and possible lead copper and aluminium
What is the purpose of the carbon filter?
> to remove/reduce chlorine levels and possibly other chemicals (e.g. Traces of pesticides)
Why is silver sometimes added to a filter in the home?
Because it discourages the growth of bacteria/microbes
What is an advantage and disadvantage of adding chlorine to the water?
> it kills the bacteria
> it is toxic in large quantities
