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Avoiding the fatberg: Turning waste oil into composite materials - Dr Stuart Coles

Avoiding the fatberg: Turning waste oil into composite materials

Dr Stuart Coles

As an Associate Professor in Sustainable Materials and Manufacturing, I’m involved with a lot of truly amazing projects. Most recently, I’ve been supervising a brilliant PhD student from Brazil, Felipe Fernandes.

Felipe’s PhD focused on working out how to turn waste oil, something that is currently converted to biodiesel, into composite materials. Waste oil is often disposed of down drains and contributes to the ‘fatbergs’ we have seen featured in the news in recent years. They pose a big problem for water companies, as it costs time, money and effort to remove them from our drains. The most common source of waste oil in the UK is from kitchens and includes fats, greases, vegetable oils, etc.

Severn Trent says up to 70% of blockages in sewers are caused by fatbergs, so by developing a polymer with industrial value, we can deal with this problem effectively and add real value in the process.

The source of oil chosen has to be easily accessible and local. We chose an abundant waste cooking oil (a blend of rapeseed oil and palm oil) from the University’s Café Library! Whilst we’ve used one particular blend for consistency, the process we’ve developed is also applicable to any blend of waste cooking oil.

First, the oil needed cleaning, so Felipe had to decide what filters to use and which impurities were acceptable in an oil-based polymer.

Next came the cleaning process itself. We took techniques from the biodiesel industry and adapted them to deal with the specific challenges of cooking oil like removing burnt batter and food. These all need to be filtered out.

Once cleaned, Felipe could focus on converting the oil into a polymer called an epoxy. We know we can make anywhere up to 100% waste oil-based epoxy, and we can tune the mixture to find the right blend to achieve the desired properties at the end.

In terms of major barriers, we didn’t really face any - this is one of the only PhD projects ever to have run relatively smoothly!

Felipe’s polymer hasn’t been used yet, but we think it will play a part in non-structural components of cars. Similar parts are used in the new BMW i3. It also has potential applications in crash structure elements - crumple zones inside bumpers etc., where the waste oil composite actually performs better than conventional materials!

What we have learnt here is applicable more widely and we will be working with other companies to develop this work further.

The PhD was funded by Science Without Borders, an initiative from the Brazilian Government and the National Council for Science and Technological Development (CNPq) They funds scholars to travel abroad, learn from institutions and bring back their new skills to Brazil. CNPq covered Felipe’s stipend, tuition fees and a budget for consumables.