Water Production Flashcards
Fresh Water Uses
• Drinking
• Washing
• Cooking
• Cleaning
Services provided by Fresh Water System
The laundry
The galley
Showers and sinks
Water heaters
Medical use
Bridge window washers
Fresh water hose reals
Machinery cooling
What is osmosis
Is the transfer of pure water through a semi-permeable membrane into salt water
What is reverse osmosis
Is the transfer of water from salt water through a semi-permeable membrane into pure water
What is TDS
Total Dissolved Solids - measure of water purity
What is the TDS of sea water
34000ppm
TDS of water after desalination
between 250 & 300ppm
What percentage of sea water is ejected
Approximately 80%
Desalination water is called
Permeate and sometimes referred to as made water
Waste water after desalination is called
Concentrate
Name the 2 filtration stages of the Reverse Osmosis Plant
Bag Filter
Cartridge filter
Bag filters down to
60 microns
Cartridge filters down to
10 microns
High pressure, 3 piston positive displacement pump
Provides 65 bar
What provides 65 bar to the Reverse Osmosis plant
The high pressure. 3 piston positive displacement pump
Salt water to the….
Cushion membranes
Cushion membranes have…..
Ultrasonically welded edges
What does the anti scaling doping unit do?
prevents precipitation of calcium salts directly forming on the membrane surfaces.
Name the anti sealant used, and the rate it is added at
Hypersperse, 5ppm
What is CCV
Concentration Control Valve
What does the CCV do?
This controls the Back Pressure of the sea water acting on the Membrane Cushions.
How does CCV work?
By Closing the valve, the back pressure is Increased and the amount of Permeate is Increased. Therefore, Opening the valve Reduces the back pressure and the amount of Permeate is Reduced.
Water passing through Reverse Osmosis Plant cannot contain….
Chlorine, as it can cause irreversible lasting damage to the membranes
What is added to water to kill bacteria
Chlorine
When are chlorine levels checked?
Daily and before Embarkation.
What rate is chlorine maintained at?
0.2ppm
When should desalination not continue?
if the source of water is likely to be contaminated. Harbour water and Estuary waters being prime examples.
Who supervises the addition of water to the water?
Section Head
Name the 3 water tests
- CHEMets
- Visual
- Taste
What are calorifiers for?
Heating the water on board
Name a kind of Air Eliminator
Water Hammer
What does the water hammer do?
a loud and repetitive banging noise inside the pipes
How are fresh water hoses used?
Blue in colour – they should be flushed with fresh water before use
Reverse Osmosis diagram
Reverse Osmosis Diagram
How can scaling of membranes be prevented
Hypersperce, 5ppm
