Let’s explore the four primary processes used around the world.
Reconditioning (Simple Cleaning)
Best for: Industrial reuse onsite
Goal: Quickly restore usability by removing solids and water.
Reconditioning is the most basic form of oil recycling. It’s a physical cleaning process that includes:
- Settling– letting heavy particles and sludge sink to the bottom
- Filtration– removing suspended solids
- Centrifugation– spinning the oil to separate water and debris
While reconditioned oil may not match new oil in performance, it’s often suitable for short-term or less demanding industrial applications.
Re-refining (Full Regeneration)
Best for: Producing high-quality base oil
Goal: Recover oil at near-virgin quality for reuse in engines and machinery.
Re-refining is the gold standard of used oil recycling. The process usually involves:
- Dehydration– removing water and light hydrocarbons
- Vacuum Distillation– separating usable oil from contaminants
- Hydrotreating– using hydrogen gas and catalysts to remove sulfur, nitrogen, metals, and acids
The final product meets or exceeds original lubricant specifications and is certified by organizations like the American Petroleum Institute (API). Many top lubricant brands use re-refined base oils in their formulations.
Burning for Energy Recovery
Best for: Large facilities with approved burners (e.g., cement kilns, factories)
Goal: Convert waste oil into heat energy
Instead of refining oil back into lubricants, some industries burn it directly in high-efficiency furnaces or boilers. Before burning, the oil must be:
- Filtered to remove hazardous materials
- Stored safely to prevent emissions or leaks
While this method doesn't reclaim oil for reuse, it does recover energy and reduce fossil fuel demand. However, it requires strict emissions controls to protect air quality.
Chemical or Solvent Extraction (Less Common)
Best for: Specialized applications
Goal: Separate oil from additives and contaminants using solvents.
This method uses chemical solvents to dissolve and extract usable base oil components. Though effective, it involves more complex handling and higher costs, which limits its use.
What Should Never Be Done
- Never mix used oil with other fluids like antifreeze, gasoline, or solvents.
- Never dump oil down the drain, into the soil, or in regular trash. Just one gallon of oil can contaminate over a million gallons of water.
Final Thoughts
Used oil isn't the end of the line—it's the beginning of a recycling opportunity. Whether you're running a small garage, a fleet operation, or just changing your car’s oil at home, ensuring proper recycling makes a real impact.
Each method of recycling has its place, depending on your goals, scale, and the oil’s condition. But they all share a common benefit: reducing waste and moving us closer to a circular, sustainable economy.
Did You Know?
Re-refining used oil takes up to 85% less energy than refining crude oil, and produces significantly fewer emissions.