As she dug past the used condoms, banana peels, clumps of hair, cigarette cartons and grimy tissues in the dumpster from behind Tallcott Hall last Thursday, sophomore Jennifer Bell also found a dirty truth.

Almost half the contents of the dumpster, by volume, were recyclable. Cans, bottles, cardboard and paper made up about 47 percent of the “trash” that students were — and are — throwing out.

Between shudders and frequent use of the word “gross,” the 10 students in the Thursday lab group of the Environmental Science class dug through a dumpster brought to the college’s composting facility, sorting items that could be recycled or composted from actual garbage.

This is the first year Susan Allen-Gil, associate professor of biology, has had her students sift through the trash. Though student groups have done it before, it’s a new project for any class.

By volume, 23 percent of the dumpster was paper; 10 percent was cardboard; 14 percent was glass, metal and plastic containers; and 2.8 percent was compostable food waste.

In the Monday lab section of the class, students found higher results from another Tallcott Hall dumpster: more than 66 percent of the so-called garbage was recyclable.

Mark Darling, the supervisor of the Recycling and Resource Management Program, wasn’t surprised. About half the contents of each campus dumpster he’s searched through since 1989 — when the college first started recycling — has been recyclable.

The average recycling rate at the college hovers around 30 percent, without all the recycling that’s being tossed in the garbage. With the compost the college generates, it jumps to 47 percent. Since 1995, the recycling rate has gone up 19 percent.

While Darling picked out dirty bottles and crumpled cardboard from the pile with the students, he said the amount of recycling in this dumpster was actually lower than usual.

And he is direct with his blame: It’s the students’ fault. Darling said the college provides bins in dorm rooms for recycling, holds a Recyclemania challenge every year and teaches first-year sustainability seminars.

“The college, administratively, has done all it needs to do,” Darling said, standing on a pile of decomposing food in the Physical Plant’s composting facility. “It’s all up to the students to make the right choice. This is a behavior they need to adopt.”

But Darling isn’t standing by passively and watching this happen. For the past four years, the Recycling and Environmental Management Program (REMP) has done dumpster audits, most famously in 2002, when REMP volunteers dumped a mountain of trash in the Campus Center Quad. They found that 46.5 percent of that pile could have been recycled — similar to this year. Now, Darling and Allen-Gil are going a step further and making the dumpster a classroom.

Before the digging started, Darling coached the assembled students about all the different items that could be recycled. Anne Stork, lecturer of biology, who oversees the Thursday lab in place of Allen-Gil, looked on.

“It looks nice at the top, but gets a little weird at the bottom,” Darling said, gesturing to the bagged trash before them. “It’s all about your ‘ick’ factor. So, um, dig in.”

“Ugh,” said  freshman Kiera Duckworth, as she dropped a bag oozing with viscous brown goop.

But the sordid nature of their task did not deter the students. In about 20 minutes, they had sorted out the contents of the dumpster, and measured and weighed the results.

As Darling pointed out, recycling isn’t just a sustainability issue, it’s also an economic one. The college gets $20 a ton for paper, between $15 and $75 for corrugated cardboard, and avoids costs by recycling cans.

But for each ton of garbage the campus generates, it pays Tompkins County $71. Last year, Darling said the college paid $63,687 for 897 tons of trash. If students picked all their recycling out of the garbage, it could save the college more than $30,000, and also make the college money.

Senior Jeff Doherty said students hear about sustainability at this college all the time, so why can’t they make the extra effort?

“The thing that struck me the most is the stuff that could obviously be recycled,” he said. “It’s just laziness.”

Duckworth agreed with him.

“We have the bins,” she said. “More people should be participating.”

But given some context, it looks like students here are good recyclers. Last year, Ithaca College placed 14th — with a recycling rate of 29.5 percent — out of 58 U.S. colleges and universities that participate in the Recyclemania Challenge, where schools compete to have the best recycling rate. Darling is particularly proud that Ithaca beat out Harvard University and Yale University, and placed first in New York state.

But there’s still a long way to go. As sophomore Laura Josephs dug through a bag, she recalled how the students in her dorm, Eastman Hall, throw out their trash and recycling.

“People usually throw their garbage into the dumpster from the balcony because the recycling bins are smaller and they can’t make it in them,” she said.

The class plans to recommend to the college how to encourage students to recycle more effectively.

Allen-Gil said recycling also saves energy and water, so if students want to “make a difference,” recycling is the easiest place to start.

As they trudged through the snow on the walk back, Stork asked her students if they should have every future class do this.

“Absolutely,” Doherty said. “Make it a staple.”