Here's How Cruise Ships Handle The Immense Amounts Of Leftover Food - Tasting Table

"On Icon of the Seas, food waste gets repurposed. Waste is converted into pellets. Along with old cardboard and biowaste, those pellets are burned as fuel to run the steam engines that partially power the ship's water park. Other food scraps are sent to the incinerator. But this system is specific to Icon-class Royal Caribbean ships."

"In the U.S. and elsewhere, maritime law allows food waste to be discharged at sea if it has been ground small enough to pass through a screen with openings no larger than 25 millimeters. The ship must be at least three nautical miles from shore to do this. If food waste is too large, it can still be dumped at sea, but the ship needs to be 12 nautical miles from land. Waste can also be incinerated or brought back to port to be disposed of."

"Viking Line's food waste is converted to biogas after the ships reach shore. Other ships, like Sun Princess, use biodigesters. Bacteria in biodigesters break waste down into greywater that can be pumped overboard or stored. Some biodigesters can reduce the volume of waste by up to 90%, according to Green Lodging News. This would reduce not just food waste but fuel consumption, since less energy would be needed to transport the smaller volume of waste."

Icon of the Seas carries about 130,000 pounds of food for a seven-day voyage, requiring waste reduction to handle meals and snacks for thousands of passengers and crew. On Icon-class Royal Caribbean ships, food waste is repurposed by converting it into pellets, which are burned as fuel alongside old cardboard and biowaste to help run steam engines that partially power the water park. Other scraps go to incinerators. In the U.S., maritime law permits discharge at sea only when waste is ground to pass a 25-millimeter screen and the ship is at least three nautical miles from shore, or 12 nautical miles if larger. Other ships convert waste to biogas or use biodigesters that can reduce waste volume by up to 90% and produce greywater for pumping or storage.

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