A SCIENTIST has launched an international initiative to prove once and for all that where there’s muck, there’s money. A “green” chemist, Prof James Clark has developed a way to squeeze valuable fuel and chemical products literally out of the rubbish bin.
To promote the idea, Prof Clark of the University of York yesterday announced his project, the Orange Peel Exploitation Company, also known as Opec. He is developing methods to take any kind of waste from orange peels to coffee grounds and process it to release valuable resources including biofuels and chemicals.
It is all about exploiting “supply chain residues”, says Prof Clark. This could be the waste stream coming from a food-processing plant or a shopping centre, or the high-volume waste materials flowing from mass production agriculture. Orange peels are a case in point, he says.
Brazil is one of the world’s largest producers of orange juice and the industry generates more than eight million tonnes of production waste a year. He wants to utilise this waste to get valuable products back out of the dump.
“From each orange squeezed to make juice, half is wasted. We can release the energy and chemical potential of orange peels with microwaves,” he tells a session at the British Science Association Festival of Science in Bradford.
Effectively, he uses a large microwave oven to cook the chemicals out of the material being recycled. The system only needs to work at about 200 degrees but this is hot enough to transform the waste and draw off useful substances. Heating up the orange peels, for example, drives off things such as d-limonene, found in many domestic cleaning products but also used in paint manufacture. But there are other substances available such as solvents, bioplastics, acid catalysts, pectin and of course biofuel, Prof Clark says.
This green approach could help dispose of waste but also turn a profit.
Energy demands are usually met by using biofuels derived from the process, but typically this represents only about 10 per cent of the useable output. That leaves about 90 per cent which can be sold to help make a profit.
Just about anything can be thrown into the microwave, he adds. “In terms of food waste it will take anything. It is very, very flexible.”
Coffee grounds offer an opportunity, he believes. Europe produces about three million tonnes of grounds a year. Food industries in North America churn out 46 million tonnes of waste a year and Indonesia’s palm oil industry delivers another 15.8 million. “The quantities are enormous.”
His lab is currently building a test system that will process 10kg of waste an hour, but he has also run a system that can handle 100kg an hour. A full commercial system would handle as much as 20 tonnes an hour, he suggests.
The challenge was to devise a product recovery scheme that matches the waste stream involved. Cooked orange peels don’t deliver the same chemicals as, say, your double espresso coffee grounds.