From Waste to Roads: Reusing Residues from Used Oil Recycling
Author Name
Aishwary Pathak
Date Published
9 February 2026
Used oil recycling is widely recognised for its ability to recover valuable base oil through re-refining. However, what often goes unnoticed is the significant volume of residues generated during this process—and the untapped opportunity they represent.
Today, these residues are largely treated as a disposal problem. Tomorrow, they can become inputs for infrastructure, materials, and energy, reshaping the economics of re-refining and strengthening the circular economy.
Residues Generated During Used Oil Recycling
When used lubricating oil undergoes re-refining, it is separated into multiple fractions. While base oil recovery is the primary objective, the process inevitably produces several residual streams:
Major Residue Streams
Vacuum Distillation Bottoms (Asphaltic Residue / REOB)
Heavy hydrocarbons rich in asphaltenes and resins
Oily Sludge
Generated from dehydration, centrifugation, and filtration
Spent Clay / Filter Media
Oil-laden adsorbents used in polishing stages
Light Ends and Contaminant Fractions
Containing degraded additives and impurities
Many of these residues still contain usable hydrocarbons, yet today they are typically:
● Sent for co-processing,
● Used as low-value fuel, or
● Disposed of at a cost.
Residue as a Resource, Not a Liability
Among the residues generated, asphaltic residue—also known as re-refined engine oil bottoms (REOB)—has emerged as one of the most promising candidates for high-value reuse.
Rather than treating this fraction as waste, recent research demonstrates its suitability for bitumen modification and road construction applications.
Bitumen and Asphalt Applications: What Research Shows
Multiple peer-reviewed studies now confirm that waste engine oil residues can be safely and effectively incorporated into asphalt binders.
Key Findings from Recent Studies
● REOB can partially replace virgin petroleum bitumen
● Improves binder flexibility and fatigue resistance
● Reduces brittleness in aged asphalt
● Enhances circular material recovery in road construction
Some studies also combine REOB with crumb rubber or reclaimed asphalt pavement (RAP), enabling nearly 100% waste-derived road materials.
The Hidden Cost Today: Paying to Dispose Residues
At present, most used-oil recyclers:
● Pay for residue disposal or co-processing
● Treat residues as a regulatory and financial burden
● Factor disposal costs into overall re-refining economics
This has two major consequences:
Higher operating costs for recyclers
Higher final price of re-refined base oil (RRBO)
In effect, recyclers recover value from base oil—while losing value on residues.
How Residue Reuse Changes the Economics
If technologies for residue reuse—such as asphalt blending—are scaled and formalised:
Economic Shift
● Disposal cost → Revenue or cost neutrality
● Residue becomes a saleable or utilisable product
● Overall re-refining cost per tonne decreases
Downstream Impact
● Lower RRBO production cost
● Improved price competitiveness vs virgin base oil
● Greater incentive for used-oil collection and compliance
Why This Matters for the Circular Economy
True circularity is not achieved by recovering one fraction and discarding the rest.
Residue reuse enables:
● Maximum material recovery per unit of used oil
● Reduced dependence on virgin bitumen and fossil feedstocks
● Lower emissions associated with disposal and incineration
● A shift from linear waste handling to closed-loop systems
Most importantly, it aligns incentives:
● Recyclers are rewarded for innovation
● Infrastructure sectors gain alternative materials
● Policymakers achieve higher recovery efficiency without subsidies
This is circular economy in practice, not just in principle.
The Road Ahead
As re-refining gains traction as a resource recovery pathway for used oil, addressing the fate of refining residues becomes critical. Reusing these residues can eliminate disposal costs, improve the economics of re-refining, and ultimately make re-refined base oil more competitive.
With suitable quality standards, audits, and end-use controls, residue-derived bitumen can:
● Eliminate disposal costs,
● Improve re-refining economics,
● And extend circularity from oil to infrastructure.
The roads we build tomorrow may well carry the final proof that nothing in used oil recycling truly needs to be wasted.