Grease is the word: The future of recycling

You've just finished frying your bacon and eggs, you serve it up and there's some oil left in the pan. What to do? Throw it away? Save it for later? No, you make building materials out of it of course!

Don't blink - you did read that right. Helen Bailey, a student at Leeds University, has travelled to America, with help from The Royal Academy of Engineering, to present her work on Vegeblock: masonry units made from recycled waste and vegetable oil.

UK caterers produce between 50 and 90 million litres of waste cooking oil each year and, in the States, restaurants produce about 300 million US gallons (1.1 thousand million litres). That's a lot of oil!

Bailey uses this waste oil as a binder (in a similar way to how linseed oil is used in paint to hold the particles together) with products such as incinerated sewerage sludge, ash and steel slag to make building bricks.

Waste vegetable oil is no stranger to recycling. However, by adding waste oil to the waste products, the oil can be encouraged to form a binder for them, and may therefore be a suitable alternative to traditional binders like clay and cement. That's good news for Bailey, good news for the building trade and good news for the environment.

Bailey has also investigated the physical and mechanical properties of the bricks - things like their weight, strength, flexibility and brittleness - compared to conventional building materials.

Part of a joint research team comprising top engineers from Leeds and Nottingham Universities led by Dr John Forth and Dr Salah Zoorob, she spoke to an audience of peers about her findings at the 21st International Conference on Solid Waste Technology and Management in the USA earlier this year.

The Royal Academy of Engineering offers an international travel grant scheme. It supports top engineering research in the United Kingdom by enabling researchers such as Helen Bailey to make study visits overseas in order to remain at the forefront of new developments both at home and overseas. The scheme benefits the applicants with their current work and ultimately, engineering in the United Kingdom, as well as maintaining the prestige of the nation's engineering overseas.

Ian Bowbrick, manager of postgraduate and professional development at the Academy: "The Royal Academy of Engineering exists to support excellence in all areas and at all levels of engineering and also to offer opportunities to our engineers. The International Travel Grant Scheme is one way of doing this. Helen's excellent work in an area of sustainability demonstrates great innovation and how engineering can help save the planet."

FUEL FOR THOUGHT

Vegetable oil can also be used as fuel. The concept dates back to 1895 when Dr Rudolf Diesel developed the first engine to run on it. He demonstrated it in Paris in 1900 and outlined an experiment using peanut oil as a fuel. "The use of vegetable oils may seem insignificant today," he predicted, "but such oils may become, in the course of time, as important as petroleum."

Virgin (unused) vegetable oil can be harvested from sunflower seeds, rape seeds, soybeans and palm oil. Vegetable oil can only be used in diesel engines, and works better in older cars; converting an engine costs between £400 and £1,200.