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Fuel From Coffee Grounds | Earth Wise

December 8, 2022 By EarthWise Leave a Comment

The world drinks a lot of coffee. Americans alone consume 400 million cups a day. Each cup of coffee results in about half an ounce of coffee grounds. Adding that up, this country produces over 6,000 tons of coffee grounds each day. While coffee grounds are not particularly harmful, that is an awful lot of waste that mostly ends up in landfills or is incinerated.

Researchers at Aston University in the UK have developed a method of producing high-quality biodiesel fuel from coffee grounds. Their study was published in the journal Renewable and Sustainable Energy Reviews.

The technique consists of growing a particular species of microalgae (Chlorella vulgaris) directly on spent coffee grounds. The coffee grounds provide both the nutrients for the microalgae and a structure upon which it can grow. Exposing the algae to light for 20 hours a day and dark for just four hours a day produced the best quality biodiesel.

Microalgae is well-known as a feedstock for biodiesel production. Previously, it has been grown on materials like polyurethane foam or nylon which don’t provide any nutrients. Using the coffee grounds as the substrate for growth means that no external nutrients are needed.

The resultant enhanced biodiesel produces minimal emissions and good engine performance and meets both US and European specifications. This feedstock for producing biodiesel is ideal since it doesn’t require any competition with food crops and instead makes use of a widely available waste product. The hope is that it may reduce the cutting down of palm trees to extract oil for biofuel. In southeast Asia, this has been a major source of deforestation and increased greenhouse gas emissions.

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Aston University researchers ‘feed’ leftover coffee grounds to microalgae to produce low emission biodiesel

Photo, posted October 13, 2007, courtesy of David Joyce via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio

Record Heat In The Arctic | Earth Wise

January 13, 2021 By EarthWise Leave a Comment

By mid-November, the Arctic stays dark around the clock and twilight does not return until the end of January. But even as winter darkness descended upon the Arctic this year, record-breaking high temperatures in the region continued. In late November, temperatures across the entire Arctic basin were 12 degrees Fahrenheit above normal and some locations saw temperatures as high as 30 degrees above normal.

The entire summer and fall in the Arctic were characterized by exceptionally warm temperatures. In June, the Siberian town of Verkhoyansk – located north of the Arctic Circle – registered a high temperature of 100.4 degrees. The refreezing of the Arctic Ocean was greatly delayed this year. The Northeast Passage along the Siberian Coast remained navigable for a record 112 days before freezing in November, breaking the previous record by more than a month. The extent of sea ice covering the Arctic Ocean in October was the lowest ever recorded for that month.

The strongest warming occurring in the Arctic is during the fall. That is because rapidly disappearing sea ice is enabling the dark waters of the Arctic Ocean to absorb heat in the summer and then radiate it back into the atmosphere until late in the fall. The Arctic region is heating up three times faster than the rest of the planet, which has led to the volume of sea ice decreasing by 2/3 in the past 40 years.

According to researchers, the extreme heat in Siberia this year would have been virtually impossible without human-caused climate change and became 600 times more likely because of human emissions of greenhouse gases.

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Record-shattering Warmth Pushes Arctic Temperatures to 12 Degrees F Above Normal

Photo, posted September 1, 2009, courtesy of the U.S. Geological Survey via Flickr. Photo Credit: Patrick Kelley, U.S. Coast Guard.

Earth Wise is a production of WAMC Northeast Public Radio.

Even The Deep Sea Is Warming | Earth Wise

November 17, 2020 By EarthWise Leave a Comment

Approximately 75% of the area covered by ocean is deep, dark, and cold. This is known as the deep sea. But even in these remote regions of the planet things are heating up.

According to a new study published in the journal Geophysical Research Letters, researchers analyzed a decade of hourly temperature readings at four depths in the Atlantic Ocean’s Argentine Basin, off the coast of Uruguay. The research team selected recording depths that would best represent the average depth of the ocean, which is just over 12,000 feet.

The researchers found that deep sea temperatures fluctuate more than was previously known. They also detected a warming trend at the bottom of the ocean. In fact, all recordings indicated a warming trend of 0.02 to 0.04 degrees Celsius per decade between 2009 and 2019. This is a significant warming trend in the deep sea because temperature fluctuations are typically measured in thousandths of a degree.

Researchers say this increase is consistent with warming trends in the shallow ocean associated with anthropogenic climate change. However, they say more research is needed to better understand what is driving the warming temperatures in the deep sea.

A better understanding of what is driving these changes could have far-reaching implications. Since oceans absorb a significant amount of the world’s heat, learning about the oceans’ temperature trends could help researchers better understand temperature fluctuations in the atmosphere as well.

The researchers hope their findings will demonstrate the need to survey deep ocean temperatures annually in order to better identify the long-term trends.

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The deep sea is slowly warming

Photo, posted July 1, 2018, courtesy of NOAA Ocean Exploration and Research via Flickr.

Earth Wise is a production of WAMC Northeast Public Radio.