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Producing freshwater on board

The daily freshwater consumption on G.O. Sars is about 10 000 liters, or 10 cubic meters. The vessel has two tanks that hold 184 cubic meters combined. That will last us almost three weeks. At the moment there is no need to restrict consumption. 

A glass of self produced drinking water.

The research vessel actually produces its own freshwater in what is called an evaporator.
- The water is boiled in a vacuum in roughly the same way as in a pressure cooker. Saltwater flows into a tank in which there is hardly any air. The result is a boiling point around 30 degrees centigrade. The steam, which contains no salt, goes through a filter in order to remove any particles. After passing through a cooler the steam then condensates and ends up in another tank as freshwater, explains first engineer Sigmund Grønnevik.

The evaporator is situated in the engine room and gets most of its warm water from engine’s cooling system. The vacuum is made by a pump. The salt remains in the evaporator’s tank which has to be emptied regularly. The evaporator’s capacity is about 10 cubic meters a day which is about equal to the daily consumption.
-Most of the water is used for on cooking, cleaning and showers. Work on the research stations also requires some water, captain Preben Vindenes says.

Sigmund Grønnevik with the evaporator which produces the drinking water.

Not often does he have this many people on his vessel. Every bed was occupied until three researchers from Bjerknes Centre for Climate Research left the ship to continue doing core sampling on South Georgia. At the beginning of the cruise, the captain encouraged the cruise participants not to be wasteful with the freshwater.
- You have to take precautions. We will only have freshwater for a few weeks if the evaporator fails, he says.
- We also have almost 100 cubic meters of freshwater in one of the bottom tanks. But that cannot be used as drinking water and we would rather not use it, says the captain.