1. Untreated sewage can lower the oxygen content of fresh water if released into it.

    True

    False

2. Which of the following is not a disease spread by untreated sewage?

    cholera

    measles

    typhoid

    dysentry

3. What do we call the jelly-like substance we use to grow bacteria?

4. When working with micro-organisms, the apparatus must be sterilised to avoid unwanted .

5. A is an organism which obtains its food from dead or decaying organic matter.

6. What useful gas is obtained from anaerobic respiration of sewage?

    methane

    carbon dioxide

    oxygen

    helium

7. Waste can be upgraded to protein rich compounds.

    True

    False

8. Alcohol is a non-renewable fuel made from the fermentation of sugar.

    True

    False

9. The liquid containing waste discharged from a sewage works is called .

10. The method of sewage treatment involving the addition of recycled decay bacteria and compressed air is called activated process.