DieselShip's Online Content Library

Q6. With reference to the treatment of domestic water for potable use.

(a) describe the principle of operation of a steriliser that uses silver irons; (4)

(b) State the advantages of silver iron sterilisation over other methods; (2)

(c) State the inspections and maintenance that should be carried out on EACH of the following;

(i) Fresh water tanks (2)

(ii) calorifiers (2)

Q6. With reference to bacteria harmful to humans in drinking and washing water:

(a) state the constraints placed on the installation and use of systems for shipboard production of freshwater; (3)

(b) state the maintenance and treatment recommended for freshwater tanks; (3)

(c) describe how the entire freshwater system can be made free from bacteria; (3)

(d) state an acceptable residual value in the freshwater tanks to ensure the correct concentration of treatment in the system. (1)

Q6. With reference to bacteria harmful to humans in drinking and washing water:

(a) state the constraints placed on the installation and use of systems for shipboard production of fresh water; (3)

(b) state the maintenance and treatment recommended for fresh water tanks; (3)

(c) describe the principle of operation of a steriliser that uses silver ions. (4)

Q6. (a) Sketch a single stage flash evaporator, labelling the component parts and showing the directions of flow. (5)

(b) Explain the term flash evaporation. (2)

(c) State the regulations governing the operation of an evaporator if the distilled water is intended for human consumption. (3)

Q7. (a) Explain the principles of osmosis and reverse osmosis. (4)

(b) Describe how reverse osmosis is used for the production of fresh water on board ship(4)

(c) State the limitation of the quality of the permeate in a single pass reverse osmosis system, describing how the quality of the permeate could be improved. (2)

Q7. With reference to the on-board production of fresh water for domestic purposes:

(a) explain the principles of operation of EACH of the following:

(i) low heat source evaporator; (2)

(ii) flash evaporator; (2)

(iii) reverse osmosis. (4)

(b) state the constraints placed on the installation and use of systems for shipboard production of fresh water.        (2)