Sludge (possibly from Middle English slutch 'mud, mire', or some dialect related to slush) [1] is a semi-solid slurry that can be produced from a range of industrial processes, from water treatment, wastewater treatment or on-site sanitation systems.

The meaning of SLUDGE is mud, mire; especially : a muddy deposit (as on a riverbed) : ooze. How to use sludge in a sentence. mud, mire; especially : a muddy deposit (as on a riverbed) : ooze; a muddy or slushy mass, deposit, or sediment: such as… See the full definition. Games; Word of the Day; Grammar; Wordplay; New Slang; Rhymes ...