- With reference to reverse osmosis plants:
(a) describe the sea water pre-treatment process before the water enters the membrane modules;(6)
(b) describe how the purity of the permeate is measured;(3)
(c) state the limits of impurity in the permeate when produced to World Health Organisation Standards.
7.
(a) Describe, with the aid of a sketch, a reverse osmosis plant, from feed water inlet, to product tank, labelling ALL components and showing the position in the system of the monitoring instruments.(7)
(b) Describe the feed water pre-treatment process before the water enters the spirally wound membrane modules.(3)
7
. (a) Describe, with the aid of a sketch, the operation of the silver ion method of water sterilisation.(6)
(b) Describe how Ultra Violet Light can be used to kill bacteria in potable water.(2)
(c) Explain the disadvantages of using Ultra Violet Light as a method of sterilisation, stating how this may be overcome.(2)
- With reference to reverse osmosis plants:
(a) explain the treatment that the feedwater undergoes to prevent blockage of the membranes;(3)
(b) describe how the purity of the water is measured and protected, stating the limits on purity set by the World Health Organisation;(5)
(c) outline the further treatment the permeated water undergoes before it can be used for domestic purpose.(2)
- Describe, with the aid of a sketch, the construction of a spirally wound membrane suitable for use in a Reverse Osmosis water making plant, identifying ALL component parts.(10)
- Explain, with the aid of sketches, the principles of reverse osmosis as a method of producing fresh water.(10)
- Sketch a line diagram of a single pass reverse osmosis plant.(10)