Elizabeth Conger (McCormick '14)

Coffee grounds: one of the most prolific sources of waste on campus. Sodexo sells coffee to sleep-deprived students and faculty through many vendors, including Starbucks, Einstein’s, and catering services. Between these sales and dining hall consumption, Northwestern’s coffee consumption produces about 415 pounds of used coffee grounds every year. Currently, these grounds are composted to make fresh soil, but their usefulness could be extended further.

Elizabeth Conger, a junior environmental engineering major, is researching a process to produce biodiesel from Wildcats’ favorite energy booster. Coffee grounds contain about 15% lipid content per unit of mass, and specific lipids known as fatty acids can be chemically converted to fatty acid methyl esters, the components of biodiesel. The chemical reactions involved in the conversion process require nothing more than common laboratory reagents, such as lye and hydrochloric acid, and heat. The remaining 85 percent of coffee ground biomass can still be used for composting, but the extracted fatty acids can help keep our university run using a little less gasoline.

The project is still in its infancy, but Elizabeth is conducting experiments to provide the greatest yields from the reactions, as well as identifying methods to collect and process grounds on a university-wide scale. In the future, if you smell a whiff of coffee in the exhaust of a Northwestern shuttle, you may rest assured that your late-night caffeine run helped provide fossil fuel-free transportation to campus.


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    Lizzy Conger is a junior in Environmental Engineering