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Earth Tub

June 10, 2008 at 11:29 am
By Margaret Taylor '10

Those dedicated SOPEers are at it again. After convincing the dining hall to use silverware made of corn, revitalizing the green roof, and founding the Sustainability Revolving Fund, SOPE has installed a new eco-friendly project on campus.

It’s called the Earth Tub, and SOPE held an open house to demonstrate how it works last Sunday. The Earth Tub looks like a giant Dumpster, but its true function is far more ecological. It’s actually a compost bin that turns food waste from campus into soil. Shaun Sawtell ’08 gave the grand tour of the bin, opening up the lid to reveal the partly-decomposed food matter inside. It was a warm day, possibly in the 80s, but the thermometer on the inside of the bin read 120º F. Sawtell says that when the SOPEers loaded the food into the Earth Tub back on April 18, the bin was about two thirds full. Now it is about one third full.

The waste inside must be kept within a specific range of temperatures for maximum decomposition to occur. It also has to be aerated, or else it will start to decompose anaerobically and turn into slimy muck, a lot like what happens at the bottom of a trash can. To keep this from happening, one of the members of the Earth Tub team (Shawn Sawtell, Clare Bansberg ‘11, Clare Bosworth ‘11, and Tess Dornfeld ‘10) must come out to the tub, which is located near the water tower, to stir it three times a week. Stirring is quite the workout: there is a rod coming out of the lid that the students must push around in a circle, like an old-fashioned grain mill. Then they check the vents of the bottom of the tub that regulate the amount of air the compost gets, and empty the bucket that collects water that drains off from the bottom of the bin.

When the process is complete, the kitchen scraps will have turned into lovely nutritious soil, which SOPE plans to give to nearby Farm House to put on their plants.

The tub isn’t responsible for composting all the food that goes into the yellow bins at the dining halls each day. All that waste gets shipped to a facility in Rosemount, which does essentially the same thing to the waste as the Earth Tub does, but on a much larger scale.

The Earth Tub was the result of a grant proposal Beth Bennet ’07 submitted to the EPA last year to fund sustainability projects on college campuses. The EPA gave Carleton $10,000 to fund the tub, and after hard work from all the SOPE folks, it is finally beginning to do its composting business.

“It’s so cool to see something we’ve worked on almost three years actually here,” says Bansberg. Dornfeld agrees. “I’m excited to see how it’ll work in the future.”

So what’s next? The college is working on plans to start a farm on campus. Katie Blanchard ’10 and Emily LeGrand ’09 are staying on campus over the summer, working with David Hougen-Eitzman to get it started. “There’s a big supply of food waste,” from campus houses and other locations in Northfield, says Sawtell, so it won’t be a problem getting fodder for the composter over the summer, even though the dining halls will be closed.