Topic 10 - Using Resources (4)

Question 1

POTABLE WATER:
What is potable water

Answer 1

water that’s been treated or is naturally safe for humans to driknk

Question 2

POTABLE WATER:
Why can’t potable water be called pure?

Answer 2

pure water contains only H2O molecules whereas potable water can contains lots of other dissolved substances

Question 3

POTABLE WATER:
What factors determine whether water is potable?

Answer 3

• levels of dissolved salts (can’t be too high)
• pH between 6.5 and 8.5
• no harmful bacteria or microbes

Question 4

POTABLE WATER:
What type of water is rainwater?
What does this mean?

Answer 4

• fresh water
• it is water that doesn’t have much dissolved in it

Question 5

POTABLE WATER:
In what two ways can water be collected?

Answer 5

• as surfae water (lakes,rivers)
• as groundwater (in rocks called aquifers that trap water underground)

Question 6

POTABLE WATER:
What is the name for the type of rock that traps water underground?

Answer 6

aquifers

Question 7

POTABLE WATER:
Explain how the source of fresh water depends on location in the UK?

Answer 7

• surface water tends to dry up first
• in areas like the south-east, most of the domestic water supply comes from groundwater

Question 8

POTABLE WATER:
Why deos water from fresh water sources still need to be treated?-

Answer 8

even though it has low levles of dissolved substances, it needs to be trated to make it safe for humans to consume

Question 9

POTABLE WATER:
Expalin the two steps in treating fresh water?

Answer 9

filtration - a wire mesh screen out larger objects like twigs, and then gravel and sand bds filter out any other solid bits

sterilisation - the water is sterilised to kill any harmful bacteria or microbes. This can be done by bubbling chlorine gas through it or by using ozone or ultraviolet light

Question 10

POTABLE WATER:
How do dry countries without enough surface or groundwater provide potable water?

Answer 10

sea water is treated by desalination

Question 11

POTABLE WATER:
Why may chemical be added to the water supply?
Give an example?
Why may this be controversial?

Answer 11

for health benefits
fluoride - good for teeth
people aren’t given a choice whether they consume them or not

Question 12

POTABLE WATER: Explain an alternative methos of treating sea water?

Answer 12

• by processes that use membranes - like reverse osmosis
  the salty water is passed through a membrane that only allows water molecules to pass through
  Ions and larger molecules are trapped by the membrane so separated from the water

Question 13

POTABLE WATER:
What is a disadvantage of both reverse osmosis and distillation to treat sea water?

Answer 13

they both need lots of energy, so they’re really expensive and not practical for porducing large quantities of water

Question 14

WASTE WATER TREATMENT:
Give 3 examples of things we use water for at home?

Answer 14

• having a bath
• going to the toilet
• doign the washing-up

Question 15

WASTE WATER TREATMENT:
Where does waster water go once it is flushed down the drains?

Answer 15

into the sewers and towards sewage treatment plants

Question 16

WASTE WATER TREATMENT:
Give two ways agriculture systems produce a lot of waste water?

Answer 16

• nutrient run-off from fields
• slurry from farm animals

Question 17

WASTE WATER TREATMENT:
Why does sewage from agricultural or domestic sources have to be treated?

Answer 17

to remove any organic matter and harmful microbes before it can be put back into freshwater sources like rivers and lakes

Question 18

WASTE WATER TREATMENT:
What would happen if we pumped untreated sewage into freshwater sources?

Answer 18

it would make them very polluted and pose health risks

Question 19

WASTE WATER TREATMENT:
Give an example of an industrial process that produces lots of waste water?

Answer 19

the Haber Process (the waste water has to be collected and treated)

Question 20

WASTE WATER TREATMENT:
As well as organic matter, what can indistrial waster also contain?
How does this change the treatment before it is safe to release it into the environment?

Answer 20

• harmful chemicals
• it has to undergo additonal stages of treatment before it is safe to release into the environment?

Question 21

WASTE WATER TREATMENT:
What additional stages could be added for treating waste water that contains toxic substances?

Answer 21

• adding chemicals (e.g. to precipitate metals)
• UV radiation
• or using mebranes

Question 22

WASTE WATER TREATMENT:
What are the four main parts of waste water treatment?

Answer 22

1- screening
2- sedimantation
3- aerobic degestion (for effluent) OR anaerobic digestion (sludge)

Question 23

WASTE WATER TREATMENT:
What is an advantage and disadvantage of sewage treatment?

Answer 23

• (requires more processes than treating fresh water) but uses less energy than desalination of salt water, so could be used as an alternative in areas where there’s not much fresh water
• some people don’t like the idea of drinking water that used to be sewage