Metal Sludge was created in 1998.

Metal sludge can be used to recover useful metals.

sludge hammer

J. Smart has written:

'Full scale studies on the thermophilic anaerobic digestion process' -- subject(s): Biological treatment, Purification, Water

'Aerobic digester sludge nitrogen/metal ratios and the sludge utilization guidelines' -- subject(s): Characterization, Recycling, Sewage sludge, Sewage sludge as fertilizer, Sewage sludge digestion

Acid Bath was a sludge metal band that first began performing in 1991. The band's career came to an abrupt halt in 1997 after Bass Guitarist Audie Pitre was killed in a car crash by a drunk driver.