It's not just airplanes either....
Apologies for thread drift. I just thought you might like to know that aviation isn't the only business with poo problems.
When in paid employment I worked for a company that had several platforms in the North Sea, pumping gas ashore. On the older platforms waste disposal was somewhat basic.
On one in particular it amounted to a pipe from the toilet pan into the sea. To avoid upsetting the supply ship crews, the pipe extended under the platform and into the sea. As you may know, the tide causes sea level to rise and fall. The flush arrangement was pretty basic, with just a flapper valve under the pan, which allowed the water and debris to drop into the sea. Now you know why I don't eat crabs.
Picture the scene when a colleague uses the facility at high tide. Having fulfilled his needs, he presses the flush. At this point the air in the pipe, having been pressurised by the rising tide vents to atmosphere, thus he got his own back. Not a pretty sight.....