Once you've finished in those cramped aeroplane loos, and that scarily noisy flush makes your waste disappear, do you ever stop and wonder where it actually goes?
While the first thought might be that it shoots out into the sky, it turns out it's something completely different – and quite complicated.
The reason the flush is so loud is because it uses strong suction to prevent blockages. When you flush the loo, a valve opens to collect all the waste that is sucked from the bowl.
The waste is then coated with Teflon to stop it from sticking to the pipes.
It then travels through the pipes, similar to your at-home plumbing – but instead of joining the sewage system, the waste is stored in tanks on board.
When the plane lands, a special vehicle attaches a hose to the sewage tank and empties it, ready for the next flight.
So next time, you can go back to your seat reassured that there's no risk of it landing on somebody's house.