Used engine oil: how to turn a problem into a valuable resource?

On a day-to-day basis, we are unlikely to think about what happens to the oil we pour out in a restaurant after a fry-up or change during car maintenance. However, every drop matters - if inappropriately managed, it can become a danger to the environment and, if well stored, a valuable resource. Used engine oil, industrial oil or cooking oil is a topic worth looking into. And that is exactly what we will do in this article.

Old Europe, new challenges - the continent's oil balance sheet

Millions of tonnes of waste oil are generated in Europe, and the scale and nature of the waste oil varies strongly depending on the source. Engine and industrial oils dominate quantitatively, while cooking oil (UCO) is gaining strategic importance as a raw material for biofuel production. This diversity makes it necessary for different countries to apply different management strategies.

In 2017 within the European Union approximately 4.3 million tonnes of lubricating and industrial oils were placed on the market. Of this amount, 1.64 million tonnes of used oil were collected - this means that approximately 38% of the oils originally placed on the market were collected. When only the proportion of oils that can realistically be recovered (i.e. around 2 million tonnes) is taken into account, it turns out that as much as 82% of this recoverable amount was collected.

However, it is not possible to recover all of it, because part of the oil is consumed during operation - for example in engines or industrial machinery - through combustion, evaporation or soaking into the consumable.

The table below shows data on oil consumption in EU countries based on the report Circularity of mineral and synthetic lubrication and industrial waste oil management in the EU of 2023. The situation of Poland is also included for comparison:

Inconspicuous waste, strategic raw material - the potential of UCO in Europe

UCO (used cooking oil), or used cooking oil, is increasingly being treated as a strategic raw material. Sourced from the catering and food industries, it forms the basis for biodiesel production. This type of renewable fuel reduces greenhouse gas emissions by up to half. It is also relatively easy to access, which makes it an attractive material to manage

According to estimates, each EU resident generates around 8 litres of UCO per year, which translates into a potential of up to 4 million tonnes per year and represents about 6% of the world production of this wasteas the article Waste cooking oils into high-value products: where is the industry going? by Valentina Beghetto, published in March this year. Meanwhile, the level of actual collection is only about 1/7th of this amount. In 2022, the global supply of UCO was around 15 billion litres and is projected to increase to 17 billion litres by 2030. The majority goes to biofuel production.

Due to low domestic supply, close to 80% demand for this waste is covered by imports. Suppliers are mainly China, Indonesia and Malaysia. A total of more than 1.4 million tonnes of imported UCO enters the EU and the UK each year

What happens to the oil after use? - european recycling map

Used oil can be managed in several ways, depending on the desired end result or the options available. The most commonly used methods are:

Re-refinement

This is the most desirable method for engine and industrial oils. The process involves distillation and hydrotreating, i.e. hydrogen purification at high temperature and pressure. This recovers the base oil, which can be reused to produce new lubricants. There are 27 re-refining plants in the EU, processing around 0.95 million tonnes of used oils per year.

Energy recovery

When the oil is too contaminated to be re-refined, it can be used as an alternative fuel. Cement factories and combined heat and power plants use it to produce heat and electricity. Although this method recovers energy, it does not allow the oil to be recirculated as a raw material and is therefore considered less favourable in the waste management hierarchy.

Transesterification

A specialised chemical process used primarily with cooking oils (UCO). It involves the reaction of oil with alcohol (usually methanol) in the presence of a catalyst, resulting in biodiesel and glycerine. Biodiesel from UCO is a second-generation biofuel that reduces greenhouse gas emissions by up to 80% compared to conventional diesel.

Export to foreign installations

Countries that do not have their own re-refining facilities, such as Belgium or Luxembourg, export used oils to countries with the appropriate infrastructure. This solution avoids illegal incineration or dumping of waste, but involves logistical costs and dependence on foreign operators.

Oil under the magnifying glass: the biggest obstacles on the road to recycling

Used oils are rarely found in their pure form. Engine and industrial oils contain heavy metals such as lead or mercury, as well as fuel residues, detergents and additives. Such contaminants mean that recycling requires complex filtration and purification processes, and some batches of oil become completely unusable.

Cooking oil (UCO), on the other hand, is contaminated with food residues, glycerol and free fatty acids. The latter cause a change in viscosity and reduce the quality of the raw material. It has to undergo costly chemical treatment before it goes into biofuel production.

An additional problem is the mixing of waste. If used oils are combined with solvents or other chemicals, the whole batch can be classified as hazardous waste. Then, instead of reuse, only incineration remains, which reduces the efficiency of the entire management system.

An equally significant challenge is the collection logistics themselves. In many European countries, the level of used oil recovery is still less than half of its potential. The rest ends up in the environment or in illegal installations, leading to serious environmental consequences.

Oil boomerang - a risk that comes back with redoubled force

Improper handling of used oil can lead to serious environmental, health and legal consequences. Even a small amount of oil can cause enormous damage - one litre can contaminate hundreds of thousands of litres of water, forming a film on the surface that cuts off the flow of oxygen. As a result, aquatic organisms die and entire ecosystems are degraded. Similar effects are observed in the case of soil - oil seeping into the ground contaminates it, reduces its fertility and thus requires costly reclamation.

The illegal burning of used oils carries additional risks. The smoke releases dangerous compounds such as PCBs and PAHs, which are carcinogenic and endanger the health of people living nearby. Cases of uncontrolled burning are not uncommon, especially where there is a lack of legal collection points. According to the European Commission's previously cited report, nearly 18% of oil waste generated is irretrievably lost through illegal incineration in smaller facilities and processing into biofuel.

Problems can also arise during transport and storage. Leaky containers lead to spills that contaminate soil and groundwater. Improper storage increases the risk of fires and explosions, especially when oils are mixed with other chemicals.

Finally, there is a legal dimension. Used oil is classified as hazardous waste in the European Union. Any company generating or collecting such waste must keep records and use licensed collectors. Lack of proper documentation, unauthorised collection or incorrect classification can result in high financial penalties and, in extreme cases, even criminal liability. Therefore, negligence in this sphere is not only an environmental problem, but also a real economic risk for companies.

Attempts to process used oils themselves are risky and illegal. They require technologies such as vacuum distillation, hydrotreating or controlled transesterification. In addition, EU regulations require any operator to register, document and transfer of waste to a licensed collector. Lack of knowledge of the law and technology can lead to serious losses - both financial and environmental.

A recipe for crisis: what to do about oil have ceased to be a problem and have become a valuable resource

Europe faces the challenge of improving the efficiency of oil management. Key recommendations include:

• Investment in re-refining infrastructure - especially in Central and Eastern Europe, where there is a lack of suitable facilities.
• Community education - especially in the catering sector, where UCO is generated in large quantities.
• Simpler collection systems - operating locally, with financial and educational incentives.
• Promoting a closed loop economy - instead of disposal, putting oil back into the industrial cycle.
• Increase legal and environmental responsibility of companies - companies should ensure compliance and work with licensed partners. One such partner is Ecologistics24, which will help with the comprehensive management of oil waste. Do you want to know more? Write to us at dispo@ekologistyka24.pl