Self-Assessment Questions (SAQs) for Study Session 7

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

SAQ 7.1 (tests Learning Outcome 7.1)

Match the following words to their correct definitions.

Using the following two lists, match each numbered item with the correct letter.

  1. non-combustible

  2. ash content

  3. biodegradable

  4. moisture content

  5. hazardous

  • a.waste that is a risk to health

  • b.waste that is decomposed by micro-organisms

  • c.proportion of solids left after waste is burned

  • d.waste that will not burn

  • e.proportion of water in waste

The correct answers are:
  • 1 = d
  • 2 = c
  • 3 = b
  • 4 = e
  • 5 = a

SAQ 7.2 (tests Learning Outcome 7.2)

List three main sources of solid waste in Ethiopian towns and briefly describe the typical composition of waste from each source.


The main sources are:

  • residential waste, which consists mostly of food wastes, plastics, paper, ash, textiles etc.
  • commercial waste, which is generally similar to residential waste but may vary with the type of business, for example, restaurants and cafes will have a higher proportion of food waste.
  • institutional waste from schools and government offices which is likely to contain more paper and less food waste.

SAQ 7.3 (tests Learning Outcome 7.3)

Suppose you are assigned as an urban WASH worker in a town where there is no information on the amount of residential waste produced. The WASH team did its own survey and, based on a sample of 34 households taken over a seven-day period, they came up with the data shown below.

  • The total mass of solid waste produced by the 34 sample households over seven days was 480 kg.
  • The average household size was 6.3 people.
  • The population of the town was 75,000.

Based on these data, calculate:

  • a.the generation rate of residential solid waste per person per day
  • b.the total amount of domestic solid waste generated per day by the town’s people.


  • a.We know that 34 households (or 34 × 6.3 = 214.2 people) produced 480 kg of waste in seven days. So the total amount produced per person is:

480 divided by 214.2 = 2.24 kg per person over seven days

The daily amount produced per person is, therefore:

2.24 divided by seven = 0.32 kg per person per day

  • b.The total amount of domestic solid waste generated by the town’s people is:

    0.32 x 75,000 = 24,000 kg or 24 metric tons per day

SAQ 7.4 (tests Learning Outcome 7.4)

What are the main health risks from healthcare waste?


Healthcare waste poses risks from physical injury (such as cuts) from needles and broken glass. Injuries of this nature also provide a route into the body for pathogens.

Healthcare waste contains many pathogens from blood, other fluids, faeces or used dressings. Of major concern are the HIV virus and the hepatitis B and C viruses.

If ingested without proper guidance (for example, if a child eats them), drugs and medicines can be toxic. Many healthcare unit chemicals are also harmful.

SAQ 7.5 (tests Learning Outcome 7.5)

Imagine that you have been asked to advise a householder on the storage of kitchen waste in the home before taking it to a communal disposal pit. Give a brief summary of your advice.


Your advice should include the following points: The waste should be stored in a container made of plastic or metal, and should not leak. It should be fitted with a lid so that small children cannot open it and insects cannot get into it. You should take the container to the disposal pit every day and empty it. After emptying, it should be rinsed with water and wiped out if necessary.

Summary of Study Session 7