follow Dictionary.com

How Well Do You Know English Slang?

activated sludge

noun
1.
sludge (def 8).

sludge

[sluhj] /slʌdʒ/
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.
Origin
1640-1650
1640-50; variant of dial. slutch, slitch, Middle English slich slime, wet mud (compare its derivative slucched muddy); apparently of expressive orig.
Related forms
de-sludge, verb (used with object), de-sludged, de-sludging.
Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2014.
Cite This Source
British Dictionary definitions for activated-sludge

activated sludge

noun
1.
a mass of aerated precipitated sewage added to untreated sewage to bring about purification by hastening decomposition by microorganisms

sludge

/slʌdʒ/
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
Word Origin
C17: probably related to slush
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Cite This Source
Word Origin and History for activated-sludge

sludge

n.

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

Online Etymology Dictionary, © 2010 Douglas Harper
Cite This Source

Word of the Day

Difficulty index for activated sludge

Few English speakers likely know this word

Word Value for activated

15
17
Scrabble Words With Friends

Quotes with activated-sludge