Sludge
WordNet
noun
(1) The precipitate produced by sewage treatment
(2) Any thick messy substance
WiktionaryText
Noun
- A generic term for solids separated from suspension in a liquid.
- A residual semi-solid material left from industrial, water treatment, or wastewater treatment processes.
- A sediment of accumulated minerals in a steam boiler.
- A mass of small pieces of ice on the surface of a body of water.