resources

Question 1

finite resources

Answer 1

finite = cannot be replaced as quickly as they are consumed

Question 2

how is sewage dealt with in the UK?

Answer 2

• the sewage is screened by passing through a mesh, removing solids and pieces of grit
• now the sewage is allowed to settle in large sedimentation tanks, which produce a liquid effluent and a semi-solid sludge, which sinks
• the sludge is taken away and digested by anaerobic bacteria, producing biogas which can be burned for electricity
• digested sludge can be used for farming at the end
• the liquid effluent contains large amounts of organic molecules and harmful microorganisms, so air is bubbled through it.
• this allows aerobic bacteria to multiply,
• which digest the organic molecules and microorganisms
• now, it can be safely discharged into nearby rivers or the sea

Question 3

desalanation

Answer 3

• desalination reduces the levels of dissolved minerals down to an acceptable level for potable water
• desalination can be done by distillation or reverse osmosis
• desalination requires a large amount of energy

Question 4

what does water require to be potable?

Answer 4

a neutral pH, low levels of dissolved solids and low levels of microbes

Question 5

potable water from aquifers

Answer 5

• the easiest way to get potable water is from aquifers, which have water that is safe to drink after being treated by chlorine
• however the water from them needs to be tested carefully beforehand because it could be polluted by farms

Question 6

potable water from waste water

Answer 6

producing potable water from waste water is only done in areas where water is scarce because it required many purification steps.

Question 7

potable water from desalanation

Answer 7

requires a lot of energy is expensive

Question 8

phytomining

Answer 8

• plants are grown on land that contains the metal compound that we want.
• they absorb the metal compound and concentrate it into their tissue
• then they are harvested and burned
• the ash produced contains a relatively high concentration of the metal compound

Question 9

bioleaching

Answer 9

• bacteria are mixed with a low-grade ore.
• they carry out chemical reactions and produce a solution called a leachate
• the leachate contains the metal compound that we want

Question 10

extracting metal from the compound

Answer 10

• copper can be displaced using scrap iron which is cheap
• it can also be extracted using electrolysis
• both allow us to extract metals from low-grade ores economically
• these do not involve digging, transporting and disposing of large amounts of rock unlike in traditional mining.

Question 11

life cycle assessment acronym

Answer 11

RAW - raw materials, get them, effect
M - manufacture / make
U - usage - recycled? once?
D - disposable - biodegradable
e - environmental
e - energy