Ok, so I’m in the air now, probably just flying over the Malaysian-Thai border and my question is this: You know how when you go to the bathroom in an airplane and flush the toilet, there is that terrible suction noise and brown and yellow both get sucked away with Paris Hilton-like strength? Well, where the hell does it all go? Not outside, I’m assuming. I’m hoping. ‘Cause I just wouldn’t be able to live with the guilt of all that sewerage over the years catapulted atop all humanity and the seven seas. I mean, can you imagine? Some traders are riding camels in the Sahara and then splat, some dude on a Boeing 777 who couldn’t find the Pepto fast enough spreads his love all over them. This just can’t be.

And while I’m at it, let me tell you how upset I get with Microsoft Word’s spell checker when writing these blog entries. You can type the name of any god damn Seattle company or landmark you like (like Boeing, for example, which got me thinking about it or Starbucks) and no problem. Try typing out Sumatra’s two biggest cities, though and you’ll see red all over the place. I should already know better – my goal by the end of the year is to avoid all Microsoft software. I would have already done it if Linux was better supported by Sony’s VAIO laptops. So excuse me while I open up Mozilla (a company clearly not based in Seattle) Composer to finish writing.

Update: Ok, so after a little googling, I found the answer. And here it is:

The typical home toilet uses a bowl filled with water. When you flush the toilet, it starts a siphon that drains the bowl. Gravity then carries the water into the septic tank or the sewer system. See How Toilets Work for details.

The problem with this approach on an airplane (or a train, bus, boat, etc.) is that the motion of the vehicle means you cannot use a bowl filled with water — it would splash out every time a little turbulence came along. Since there is no bowl of water, you cannot use a siphon or gravity to empty the bowl.

Airplane toilets use an active vacuum instead of a passive siphon, and they are therefore called vacuum toilets. When you flush, it opens a valve in the sewer line, and the vacuum in the line sucks the contents out of the bowl and into a tank. Because the vacuum does all the work, it takes very little water (or the blue sanitizing liquid used in airplanes) to clean the bowl for the next person. Most vacuum systems flush with just half a gallon (2 liters) of fluid or less, compared to 1.6 gallons (6 liters) for a water-saving toilet and up to 5 gallons (19 liters) for an older toilet.

If you didnt’ know, now you know.

Word.