WASTE WATER TREATMENT

Question 1

name 3 sources of waste water

Answer 1

agricultural
domestic
industrial (making paper and chemicals- any harmful chemicals need to be removed and then the water can enter general sewage treatment)

Question 2

explain the process of waste water treatment

Answer 2

• the wastewater is SCREENED to remove solids and pieces of grit
• the sewage is allowed to settle in large SEDIMENTATION TANKS
• this produces a liquid effluent and a semi -solid sludge which sinks
• the sludge is taken away and digested by ANAEROBIC BACTERIA
• this bacteria produced biogas which can be burned for electricity
  the digested sludge can be used as fertilizer for farming
• the liquid effluent contains large amounts of organic molecules and harmful microorganisms
• air is bubbled through the liquid effluent this allows aerobic bacteria to multiply
• the aerobic bacteria digest the harmful microorganisms and the organic molecules

the liquid effluent is then discharged in rivers

Question 3

what is the easiest way to produce potable water

Answer 3

with groundwater from aquifers as this is useful safe to drink after chlorine has been added
BUT SOMETIMES AQUIFERS CAN BE POLLUTED WITH FERTILIZER FROM FARMS

Question 4

why is producing potable water from sewage not ideal

Answer 4

it takes many purification steps so this is only done in places where water is scarce

Question 5

why is producing potable water from salt water not ideal

Answer 5

it needs to be desalinated to produce potable water which requires a lot of energy and is expensive