Eutrophication

Question 0

Name 2 complex ions which pollute rivers and lakes

Answer 0

Nitrates (NO3 -)

Phosphates ( PO4 3-)

Question 1

What is eutrophication?

Answer 1

The deoxygenation of water caused by enrichment of water with nutrients such as nitrates and phosphates

Question 2

What happens in eutrophication? - 7 points

Answer 2

1. Influx of nutrients into water ( fertilizers, untreated sewerage)
2. Excessive growth of algae (algal bloom)
3. Acts as a blanket, blocks light from plants in water, less photosynthesis
4. Short life span, algae die.
5. Population explosion of bacteria
6. Bacteria decompose the dead algae, high rate of respiration, use up the dissolved oxygen in the water
7. Water becomes deoxygenated and fish die

Question 3

At what stage of the treatment of sewerage are nitrates and phosphates removed?

Answer 3

Tertiary stage