desludge

noun

1. mud, mire, or ooze; slush.
2. a deposit of ooze at the bottom of a body of water.
3. any of various more or less mudlike deposits or mixtures.
4. the sediment in a steam boiler or water tank.
5. broken ice, as on the sea.
6. a mixture of some finely powdered substance and water.
7. sediment deposited during the treatment of sewage.
8. Also called activated sludge. Bacteriology. sewage sediment that contains a heavy growth of microorganisms, resulting from vigorous aeration.
9. a fine, mudlike powder produced by a mining drill.

noun

1. soft mud, snow, etc
2. any deposit or sediment
3. a surface layer of ice that has a slushy appearance
4. (in sewage disposal) the solid constituents of sewage that precipitate during treatment and are removed for subsequent purification

n.

“mud, mire, ooze,” 1640s, of uncertain origin, possibly a variant of Middle English slutch “mud, mire,” or a variant of slush (n.).