Fresh water

Question 1

State the uses of fresh water.

Answer 1

1. Drinking
2. Washing
3. Cooking
4. Cleaning

Question 2

What services are provided by the fresh water system?

Answer 2

1. Laundries
2. Galleys
3. Showers and sinks
4. Water heaters
5. Medical use
6. bridge window washers
7. Fresh water hose reels
8. Machinery cooling

Question 3

What is osmosis?

Answer 3

The transfer of pure water through a semi-permeable membrane into salt water.

Question 4

What is reverse osmosis?

Answer 4

Is the transfer of water from salt water through a semi-permeable membrane into pure water.

Question 5

Define TDS

Answer 5

Total dissolved solids

Question 6

What is TDS the measurement of?

Answer 6

The measurement of water purity

Question 7

What is the TDS of sea water?

Answer 7

34,000ppm

Question 8

What is the TDS of water after desalination?

Answer 8

Between 250 and 300ppm

Question 9

What percentage of sea water is ejected after fresh water is produced?

Answer 9

80%

Question 10

What is desalinated water called?

Answer 10

Permeate or made water.

Question 11

What is the waste water called after desalination?

Answer 11

Concentrate

Question 12

What does CCV stand for?

Answer 12

Concentration control valve.

Question 13

What happens if the CCV is closed?

Answer 13

Back pressure increases and permeate production increases.

Question 14

What happens if the CCV is opened?

Answer 14

Back pressure is reduced and permeate production is reduced.

Question 15

What will happen to the RO plant if the water passing through it contains too much chlorine.

Answer 15

Chlorine will cause irreversible damage to the membranes.

Question 16

How are the cushion membranes joined together at the edge?

Answer 16

Using ultrasonic welding

Question 17

What is the pressure of the water supplied by the piston pump in the RO plant?

Answer 17

65 bar

Question 18

What does the bag filter in the first stage of filtration within the RO plant filter down to?

Answer 18

60 microns

Question 19

What does the bank of cartridge filters in the second stage of filtration within the RO plant filter down to?

Answer 19

10 microns

Question 20

Why is chlorine added to the permeate?

Answer 20

To kill off any harmful bacteria.

Question 21

How often are chlorine levels checked in the fresh water tanks?

Answer 21

Daily and before embarkation.

Question 22

What level are chlorine levels maintained at?

Answer 22

0.2ppm

Question 23

Who authorises and supervises the addition of chlorine?

Answer 23

The section head

Question 24

State the 3 fresh water tests that are carried out?

Answer 24

1. CHEMets
2. Visual
3. Taste

Question 25

How often is fresh water testing carried out?

Answer 25

Daily and prior to embarking

Question 26

What is used to heat water on board ?

Answer 26

Calorifiers

Question 27

What causes a ‘‘water hammer’’?

Answer 27

Air in the fresh water system

Question 28

What colour are fresh water hoses?

Answer 28

Blue

Question 29

What should be done to the fresh water hoses before they are used?

Answer 29

They should be flushed with fresh water.