A macerator, in sewage treatment for example, is a machine that reduces solids to small pieces in order to deal with rags and other solid waste. Macerating units use grinding, chopping, cutting and blending mechanisms to reduce waste to a slurry, which can then be moved by pumping. Maceration equipment is often used in domestic situations (kitchens, toilets) as well as in sewage and wastewater treatment plants.

In environmentally sensitive areas such as the Antarctic, in research stations with an average summer population of more than 30 people, maceration is the minimum treatment required before sewage can be disposed of in the sea. Similarly ships at sea use maceration equipment to discharge wastewater that includes sewage and food waste.

In food processing plants, maceration refers to the use of a chopper pump, or high speed rotational blades, to create a "blended" slurry of food waste and other organic by-products. The macerated substance, which can be described as a protein-rich slurry, is often used for animal feed, fertilizer, and for co-digestion feedstock in biogas plants.

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