SAQs

Now that you have completed this study session, you can assess how well you have achieved its Learning Out comes by answering these questions.

Composting is an example of waste recycling but it could also be described as an example of recovery from waste. Explain why this statement is true.

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Composting is an example of recycling because the waste is reformed into a new material, compost, which is different from the original waste. It is also an example of recovery because the compost has value as a soil improver and has been recovered from the waste.

The waste management hierarchy is shown in Figure 8.7 below but without labels.

Add the correct terms to the five label lines on the right side of the diagram.

Figure 8.7 The waste hierarchy.

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Figure 8.8 The waste hierarchy.

Tigist is a mother of three children aged between 6 months and 5 years. Her husband has a good job and the family are well-off. Tigist does most of her shopping in the local supermarket where they give plastic carrier bags to all their customers.

Give three examples of ways Tigist could reduce the amount of waste produced by her household.

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There are several possible answers but you may have thought of the following:

  • When she is shopping, Tigist could look for products with less packaging. She could buy fresh food bought loose in a market rather than packaged food from the supermarket.
  • She could take her own bags to the supermarket so that she didn’t have to use theirs and get new ones on each visit.
  • For the baby, she could use washable nappies instead of disposables.
  • She could use the clothes that the older children have outgrown for the younger children.

In your job as a WASH worker, one of the korales has told you that they can’t collect much waste paper from a particular kebele because it is too dirty. How would you explain to the householders how and why they should separate their waste paper?

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You could explain that separating wastes into different types makes it easier to reuse and recycle. Separation should be done in the home so that the different types do not get mixed up together. If householders sorted out their waste paper and ensured it was not made dirty by food and other wet waste, this would make it more usable. If it was clean, the korales could take it away so the householders would not have to dispose of it themselves. You could also explain about the social benefits to the korales and the wider environmental benefits of reducing waste.

Which of the following statements are false? In each case explain why it is incorrect.

  1. Biogas is produced from organic waste in an open tank called a digester.
  2. Removing plastic from waste is important for both composting and biogas production.
  3. Compost piles must be turned regularly because composting is an anaerobic process.
  4. Composting and anaerobic digestion both produce material that can be used to improve soil.
  5. Methane makes up about 60% of biogas.

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1 is false. Biogas is produced in a digester but the tank must be sealed, not open because it is an anaerobic process.

3 is false. Compost piles must be turned regularly but this is because it is an aerobic, not anaerobic, process.

آخر تعديل: السبت, 1 أكتوبر 2016, 1:52