Macerating toilets use a grinding or blending mechanism to reduce human waste to a slurry, which can then be moved by pumping.
[6] Only toilet paper and human waste should be flushed down the drain; even items labeled "flushable" can cause problems.
At Antarctic research stations with an average summer population of more than 30 people, maceration is the minimum treatment level required before sewage can be disposed of in the sea.
Research stations that do not meet this population threshold are allowed to dump untreated, unmacerated sewage directly into the sea.
[1] The treaty also allows ships carrying more than ten people to discharge macerated wastewater (including sewage and food waste) directly into the sea, provided that the vessel is more than 12 nautical miles from shore.