topic 10 - using resources (8. waste water treatment)

Question 1

sources of waste water

Answer 1

sewage

run off from agricultural fields

Question 2

stage 1 of waste water treatment: screening

Answer 2

removing any large bits of material

Question 3

stages of water waste treatment

Answer 3

screening
sedimentation
aerobic digestion
anaerobic digestion

Question 4

stage 2 of waste water screening: sedimentation

Answer 4

heavier suspended solids sink to produce sludge

effluent floats on top

Question 5

stage 3 of waste water screening: aerobic digestion

Answer 5

effluent removes and treated by biological aerobic digestion

when pumped through water to encourage aerobic bacteria to break down organic matter

Question 6

stage four of waste water screening: anaerobic digestion

Answer 6

sludge from bottom of tank removed and it gets broken down by bacteria releasing methane gas (used as energy source) the remaining waste can be used as fertilizer

Question 7

what is different in the screening of waste water if the water contains toxic substances

Answer 7

may add chemicals

UV radiation or use of membranes