From kitchens to fuel tanks: how cooking oil is recycled

Food businesses know that used cooking oil is important in waste management. But not all of them are made aware of the great potential that this ‘waste’ has.
Cooking oil
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Food businesses generally understand that the way they handle their used cooking oil, or UCO, is an important part of waste management. But something not all of them are made aware of is the great potential that this ‘waste’ has.

Also referred to as yellow grease, UCO is the oil that has been used to cook food in catering establishments, such as restaurants and hotels. It is considered a catering waste, but UCO is much more than that: it has become a major source for biodiesel production, which replaces fossil fuels used for transport.

Every year, the hospitality sector in the UK creates more than 100,000 tonnes of used cooking oils and fats. If allowed to enter drains, these substances can cause blockages, odours and vermin infestations. They can also pollute water sources, harming our wildlife. 

UCO and the kitchen

Businesses that produce UCO have a duty of care to store and dispose of their waste correctly. Any UCO must be stored safely, in leak-proof containers with fitted lids, in a secure area away from drains. It must then be collected by a registered waste carrier, who should provide the establishment with a waste transfer note, to make sure that it is being disposed of responsibly. 

In part, this is to safeguard the food chain, to ensure that UCO is not being used as part of animal feed operations. Previously, UCO was added to animal feed as a cheap way to increase its calorific value. But the discovery that this can promote the spread of diseases, such as bird flu, due to the animal proteins present in the oil, led to a change in legislation. UCO used for cooking meats is now banned from being used as animal feed.

The only UCO still permitted to enter the animal food chain is that from food manufacturing industries such as crisp producers, where the oil has had no contact with meat or animal fats. This change created opportunities for alternative uses for waste oils, and it is now a major biodiesel feedstock – a renewable resource that can be used directly as an energy source or converted into one. 

A sustainable energy source

With alternative end-use options being deep landfill or incineration, recycling into biodiesel has become the accepted method for UCO disposal. Many companies will deliver fresh cooking oil and collect waste oil in one visit, reducing transport and emissions, and they often offer a monetary incentive for this combined service. 

After the UCO has been collected, it is filtered and pretreated to remove moisture and any impurities. It is then chemically converted into biodiesel at a recycling plant. Some companies have taken this technology even further to create a closed recycling loop.

With carbon savings of 88% compared to fossil fuel diesel, it’s not surprising that biodiesel is increasingly being used to power transport. And since 2011, the dominant feedstock for this renewable fuel in the UK has been UCO. In 2019, 79% of all biodiesel produced in the UK was made from this catering waste. 

A global market

This has become a worldwide market, one which was worth $5.50 billion in 2019. In many countries, UCO must be proven to be disposed of safely at a biodiesel plant, and without these rules in place, it would be sent to landfill or poured down drains. As a result, various countries export theirs for conversion: the biggest source for biodiesel supplied to the UK in 2019 was UCO from China, which made up 32% of all biodiesel feedstock.

This establishment of global UCO markets has, however, led to concerns around the traceability and sustainability of the feedstock. While current standards are good, some are calling for more rigour across the supply chain to ensure that all individual sources of UCO can be accurately traced. 

With over half of the UK’s verified renewable fuel being produced from UCO, demand for it as a resource has increased rapidly. But the COVID-19 pandemic has affected all aspects of the economy, and the UCO market is no exception.

The shutdown of hospitality in many countries has greatly reduced the supply of UCO, disrupting the global supply chain and European UCO imports, in particular, have slumped. However, many buyers have become more aware of how lockdown measures are impacting UCO demand and key market players have learned to adapt their strategies.

This means that the market has continued to grow and is expected to take off again once the food industry reopens following the pandemic, re-establishing the role of UCO as an invaluable resource in the fight to reduce greenhouse gas emissions.

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