noun / verb

sludge

SLUJ/slʌdʒ/

A heavy thick mixture of liquid and waste.

The scoop holds a heavy mound of sludge from the shallow metal tray.

A shallow, unmarked metal tray holds thick gray-brown sludge, with a small scoop resting in it and a heavy mound of wet mud clinging to the scoop.

Etymology

Its origin is uncertain: it may be a variant of Middle English slutch, “mud, mire,” or of slush. Its earliest recorded meaning already describes mud, mire, or ooze.

In context

QHSE Talks7:37

Whereas a drum of industrial waste with, say, sludge at the bottom and solvent on top is a heterogeneous mixture.

ASP 11 Domain 6 Topic 2 | General Chemistry Concepts | Industrial Hygiene & Occupational Health

More examples

The plumber removes greasy sludge from the kitchen drain.
The treatment plant separates sludge from the wastewater.
Without regular oil changes, the engine can sludge up.

Forms

sludge · sludges · sludged · sludging

sludgy adjective — Thick, wet, and sticky like sludge.

Similar words

muck: Muck usually means wet dirt, not specifically waste residue.
sediment: Sediment settles out of liquid and need not remain wet.
mud: Mud is wet earth rather than a mixture of waste.