Without some kind of a reliable solution, we could easily find ourselves floating in a land of salt water without a drop of fresh water to drink.
During my tour of the engine rooms with Second Engineer Mark O'Reilly, I was amazed to see how the S.A. Agulhas II tackles the issue of fresh water. First, the ship does have a tank of fresh water, but it is not large enough to hold all the water we would need for most journeys. So, the ship makes its own fresh water! Using a process called desalination (the removal of salt), we suck in a bunch of salty sea water, and the heat of the engines brings it to a boil. As the water turns to steam (water vapor), it leaves behind all the disolved salt. The ship captures all of that steam, which eventually cools and re-takes its liquid form again, this time without salt and ready for use by humans. Amazing, right?
This process requires a lot of engine heat, so you can imagine that we ran into some problems when we were stationary in the ice for several days at a time. The desalination system couldn't keep up. We had plenty of water for drinking and cooking, but for two or three weeks the laundry was closed and Captain Knowledge asked all passengers to take short showers. This was easy to do--who really wants to do laundry anyway! As soon as we left the Weddell Sea and began our journey back to Cape Town, our water shortage was over and the Captain lifted all water restrictions.
You may wonder, what happens to all the "dirty" water that comes through sink/shower drains and toilets? The S.A. Agulhas II has its own waste water treatment plant onboard.
