A thousands of passengers and crew travel by the cruise ships on a single trip which go on to sail for weeks at times. During this period, of course, every passenger and crew takes a dump on board. Hence generating a huge amount of waste every single day – but where does it all go? Is it simply dumped into the sea?
Sewage on a cruise ship includes waste water from toilets, urinals, medical sinks and other similar facilities. Anything which is discharged into the sea goes through rigorous treatment first as it is a requirement of an international convention called MARPOL, the sailors are very familiarised with this term!
We won’t get much technical here, in simple words, as per MARPOL requirements, all sewage on board the ship passes through a sewage treatment system that is certified in accordance with international regulations, prior to its discharge into the sea.
For ships not using onshore reception facilities and travelling regularly on itineraries beyond the territorial water of coastal states, discharge is to take place only when the ship is more than four nautical miles from the nearest land and travelling at a speed of not less than six knots.
Well this was about what the requirements are, watch this informative video to understand what actually happens when you flush the toilet on a cruise ship: