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Waste Coffee Grounds Can Be Used to Make Biodiesel and Electricity


coffee-groundsThe American Chemical Society (ACS) 246th National Meeting and Exposition, held between 8th and 12th of September in Indianapolis, yet again impresses the audience with numerous exciting talks and innovative research.

Among the presenters was a team from University of Cincinnati, who showed their preliminary findings from an experiment they conducted on the use of waste coffee grounds as a source for cheap and clean biofuel for cars and heating devices.

The morning coffee for many of us is the essential substance that can either ‘make or break’ our day. Every morning, however, we throw away a huge amount of waste coffee grounds, without even thinking that we might be able to put these into yet another great use, and reduce the amount of waste going to landfills at the same time.

This is exactly the idea that Yang Liu, a graduate student in environmental engineering in UC’s College of Engineering and Applied Science (CEAS), fellow researcher Qingshi Tu, a UC doctoral student in environmental engineering, and Mingming Lu, a UC associate professor of environmental engineering, had in mind. No wonder the project proposal was one of the four, granted with funds last year from the UC Invents initiative, an enterprise led by UC Student Government and the UC student chapter of the Association for Computing Machinery to share ideas and encourage innovation in campus life.

The scientists tested three different uses of waste coffee. Firstly, they extract oil from the coffee grounds, then they dry the remaining waste in order to create a cheap alternative for purification products used in biodiesel production, and finally whatever is left was burnt to produce electricity, following the same method as burning biomass.

As you can imagine, the experiment required quite a substantial amount of coffee grounds, hence the team turned to one of the nation’s favorite Starbucks. They collected a generous amount of waste coffee in a five-gallon bucket, which was then treated to extract the triglycerides oil and converted into biodiesel. The produced fuel was then purified using the dried remains of the coffee grounds.

The results were quite promising. The biodiesel that they produced meets the ASTM International D6751 standard. The use of dried coffee grounds as a purification product was not as impressive, but considering the price of commercial products, an alternative would be welcome, hence why the continuation of the research will focus on improving this method.

Biodiesel production from biomass seems to be a hot and controversial topic this week. Today the EU parliament is deciding on setting limits on crop-based fuel production, because of the increased use of palm oil which has a devastating impact on the environment.

Let’s hope that more techniques like the one developed by the UC research team get the green light, and clean biofuel takes its deserved place among the efficient renewable alternatives to fossils.

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