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QUESTION 1
(a) Explain why it is undesirable to discharge storm water into a foul water sewer.
(1 mark)
(b) What is trade waste?
(1 mark)
(c) Name TWO special purpose interceptor traps.
1
2
(1 mark)
(d) What TWO factors determine the size of a grease trap?
1
2
(1 mark)
(e) State the purpose of a drain vent pipe.
(1 mark)
(f) State FOUR adverse effects to the operation of a drainage system if it is not adequately ventilated.
1
2
3
4
(2 marks)
Total 7 marks
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Question1
a) If heavy rain should ever occur this would overload the foul water sewer system.
b) Any liquid, with or without matter in suspension or solution therein, that is or may be discharged from trade premises in the course of any trade or industrial process or operation, or in the course of any activity or operation of a like nature; but does not include storm water. example: cooking oil from a restaurant.
c)
1. Oil and Petrol Interceptor trap
2. Garage Sump
3. Neutralising trap
d) The capacity of the Grease trap shall be at least twice the capacity of the fixtures and appliances discharging to it, and in no case less then 100 litre
2. For restaurants, the capacity of the grease trap shall be at least 5 litres for each person for whom seating is provided.
e) 1. Introduces fresh air and removes foul air.
2. Dries out growths within the drain
3. Promotes an even flow of liquids within the drain
f)
1. Deadly gases can be produced
2. Growth in drains could cause blockage
3. Flow capacity will be restricted