1. Residue left after acid treatment of petroleum oils.

2. Any semisolid waste from a chemical process.

See <<sewage sludge>>

1. Mud from a drill hole in boring.

2. Sediment in a steam boiler.

3. A precipitate from petroleum oils or liquid fuels, for example, the insoluble degradation products formed during the operation of an internal combustion engine.

4. An amorphous deposit that has accumulated on the surface of a tube in a heat exchanger or of an evaporating device, but is not bonded to the fouled surface.

5. See <<slime>>

A soft or muddy bottom deposit as on tideland or in a stream bed.

A dense, soupy accumulation of new sea ice consisting of incoherent floating frazil crystals. Also known as cream ice; sludge ice; slush.