It is estimated that approximately 37 million tons of
lubricants are used in the world each year. Approximately
10% of these lubricant products are used in systems where
the waste lubricant is discarded directly into the
environment. It is also estimated that 13 to 32 % of used
lubricants are returned to the environment in a state where
they are essentially unchanged [12]. Environmental
protection and conservation of non-renewable resources
require significant consideration.
Although most lubricants are made from mineral oils,