Used Motor Oil or Waste Lube Oil can really be useless and toxic. A drop of Used lube oil can contaminate thousands and thousands of gallons of water.
It sticks to metals,
It is slow to degrade,
It is the major ingredient of oil contamination of waterways and
It ends up polluting sources of drinking water.

Used oil to SN150 grade Light Base Oil & SN500 grade Heavy Base Oil in distillation + wiped film Used Oil Refinery Plant Refining Process consists of two sections:
Pre-treatment (De-metallization /Ash Removal)
Separation of light ends by Distillation
Separation of oil fractions by thin film evaporation.
Finishing stage with option of Solvent / Hydrofining treatment process