sludge

[sluhj]

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.

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

Other Word Forms

• de-sludge verb (used with object)

Word History and Origins

Origin of sludge¹

First recorded in 1640–50; variant of dialectal slutch, slitch, Middle English slich “slime, wet mud” (compare its derivative slucched “muddy”); apparently of expressive origin

Word History and Origins

Origin of sludge¹

C17: probably related to _slush

Example Sentences

Few things better represent life’s varied ephemeralities than being excited about fall foliage’s exploding colors, just before the leaves die and become the primary ingredient in wintry, brown sidewalk sludge.

From Salon

Campaigners have previously complained that dredged sediment fills nearby rock pools with a "black, thick, slimy, petrochemically smelling sludge", which is toxic to people and the environment.

From BBC

The scale of 374Water's current technology is small: it can handle just a fraction of the tonnes of wet sludge the facility produces daily.

From BBC

Rescue operations are progressing at a slow pace as there is a large amount of sludge and debris covering the area.

From BBC

These are chemicals used in construction to bind soil and prevent erosion, but if they escape into the water system, they can create sludge.

From BBC

Related Words

• goo 
• grease 
• gunk 
• muck 
• sediment 
• silt 
• slime