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
1640-50; 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.
Examples from the web for sludge
  • Now the rains turn the roofs to sludge, which causes buildings to collapse.
  • Tiny bits of food get caught up in that calcified bacterial sludge, where they can remain for millennia without disintegrating.
  • From there, they can wash down drains, ultimately ending up in the sewage sludge of wastewater treatment plants.
  • The remaining sludge is processed to recover cobalt, which is used to make battery electrodes.
  • They are developing a technique that employs ultrasound, rather than pumps, to break up the sludge.
  • Finally, some organic fertilizers contain sewage sludge, leftover from wastewater treatment plants.
  • He urged the urgent installation of a new pumping station and upgrades of the high-density sludge treatment works.
  • It is a thick brown sludge, gritty and triggering an immediate gag reflex.
  • He climbed down into several more manholes to scoop up clots of sludge.
  • Even in a beaker, bacteria in ocean bottom sludge survive by sharing.
British Dictionary definitions for sludge

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
Word Origin and History for sludge
n.

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