Fresh Water Flashcards
FRESH WATER SYSTEMS.... Read the title you mong
State the uses for fresh water on board
Drinking
Washing
Cooking
Briefly state the purpose of reverse osmosis
To remove the salt from seawater making it safe to drink
What is TDS?
What is TDS measuring?
Total dissolved solids
Measures the amount of salt dissolved in the water
What is the TDS level of a concentrate?
56000 parts per million
What is the TDS of sea water?
34000 parts per million
What is the TDS of permeate?
250-300 parts per million
How much salt water is ejected?
80%
What types of filter are fitted to an RO plant?
What level do they filter to?
Bag filter - 60 microns
Cartridge filter - 10 microns
Cushion membranes
Briefly explain the reverse osmosis plant pump
High pressure pump to push the water through the membranes which increases flow but reduces the quality
Up to 65 bar
What does the CCV do?
Fitted to the discharge lines. Controls the pressure behind the membranes by opening and closing the valves to keep the flow of made water at a set level
How is scaling of the membranes prevented?
By the use of anti scaling dosing agent (chlorine maintained at 0.2ppm) which is continuously supplied to the salt water by diluting it in made water
Briefly explain the alongside procedures for bringing on fresh water
Fresh water hoses are blue
They should be flushed with freshwater before use
What is the chlorine limit?
0.2 parts per million
How often is water tested for chlorine?
It’s checked daily before embarkation
What tests are performed on fresh water?
CHEMets
Visual
Taste
