Most food service operations produce some amount of spent coffee grounds. Even in K-12 schools, cafeterias, staff lounges, and administrative offices often serve coffee for the adults on site. I intend to write posts in the near future about some of the more traditional ways to divert spent coffee grounds from landfill (e.g. composting, use as a substrate for growing mushrooms, etc.). But a recent news article has prompted me to highlight a diversion strategy for this material which you may not have considered: feedstock for the production of biofuels.
You may be familiar with using spent cooking oil or grease for the creation of biodiesel. See the archived activity on diversion of waste cooking oil for biodiesel creation for more information. Coffee grounds also contain oils that can be useful in creating biofuels. As reported in the May 10, 2017 issue of Science Daily, a group of researchers from Lancaster University in the UK recently found a way to improve the efficiency of converting coffee grounds to biofuel. Their methods reduced the time required for the process, as well as the amount of chemicals used and chemical waste produced. According to the article: ‘”Our method vastly reduces the time and cost needed to extract the oils for biofuel making spent coffee grounds a much more commercially competitive source of fuel,” said Dr Najdanovic-Visak, Lecturer in Lancaster University’s Engineering Department. “A huge amount of spent coffee grounds, which are currently just being dumped in landfill, could now be used to bring significant environmental benefits over diesel from fossil fuel sources.” The process has the potential to enable 720,000 tonnes of biodiesel to be produced each year from spent coffee grounds.’
On October 2, 2018, Ohio-based Dunkin’ Donuts Coffee at Home introduced a “tiny home” in New York City’s Madison Square Park which is powered by biofuel created from spent coffee grounds. The biofeul is a custom B80 blend created by Blue Marble Biomaterials–80% of the fuel is oil from Dunkin’ coffee grounds and 20% is alcohol to allow the fuel to burn efficiently. The “Home that Runs on Dunkin'” will be open to the public in Madison Square Park in New York City, on Broadway between 23rd and 24th Streets from Thursday, October 4 through Saturday, October 6. If you’re curious but not in NYC, check out the 360 video tour available at https://www.dunkinathome.com/whats-new/home-runs-on-dunkin. According to that site, “Every 170 pounds of spent coffee grounds yields about one gallon of fuel and is used in a standard biofuel generator.” The site also states that 65,000 pounds of spent Dunkin’ coffee grounds were used to create the biofuel.
Blue Marble Biomaterials is based in Missoula, MT. Learn more about them at https://bluemarblebio.com/.
Of course, this particular solution isn’t practical for small generators such as a single school, restaurant, or hospital. But restaurant and hotel chains or large institutions, particularly those in areas where on-site composting is infeasible and where commercial composting service is not available, might be interested in exploring the possibility of partnering with a biofuel producer to divert coffee grounds from landfill. To assist in such investigations, see the National Biodiesel Board’s map of member plants at http://biodiesel.org/production/plants/plant-maps#map. You could also reach out to colleges and universities in your area to see if scientists on campus are conducting biofuel research and might be interested in using your spent grounds as feedstock in their experiments.