water production Flashcards
what is osmosis
diluting salt water with fresh water
what is reverse osmosis
pressure is applied to salt water through the membrane to remove the salt which leaves fresh water and salty brine which is discharged as waste
how much fresh water will you get from reverse osmosis
20% of what you put in
so if you put 1000L of salt water in you will get 200L of fresh water
what is the purified water referred to as
made water or permeate
what does TDS stand for
total dissolved solids
what is the TDS of sea water
approximately 34000ppm
what is the waste water called
concentrate
what is a pre filter
cleans the water before the HP pump in two stages
uses a bag filter which filters the water to 60 microns
what does the concentration control valve (CCV) do
Closing down on this valve increases the pressure in the system (back pressure). This allows reverse osmosis to take place
what does the O seal do on the cushion membranes
prevents cross contamination between salt and fresh water
what are made water tanks
stores the ships fresh water (350ppm TDS)
when are chlorine levels checked and what is it maintained at
daily and before embarkation
maintained at 0.2ppm
who authorises the addition of any chloring to fresh water
the section head
what services does the fresh water supply
- the laundry
- the galley
- showers and sinks
- water heaters
- medical use
- bridge window washers
- fresh water hose reels
- machinery cooling
- gas turbine washing
what is the alongside procedure (14 points)
- Draw designated fresh watering hoses and connections from the store.
- Unscrew the deck cap to the filling connection
- Fit the filling gooseneck to the filling connection/Pressure Relief Valve
- Connect hoses to the shore water supply.
- Open the shore filling supply valve and flush through the hoses.
- Carry out water tests - only continue to next stage if tests ok.
- Shut off shore filling supply valve
- Connect hoses to deck filling gooseneck.
- Dip and record level in tank(s) to be filled
-Opening up the tank filling valve - Open up the shore filling supply valve
-Open up the ship’ main fresh water filling isolating valve. - Regularly check the tank’s content level.
- As applicable, regularly take water samples and test accordingly.
