Travis Wagner teaches in the University of Southern Maine’s Department of Environmental Science and Policy and coordinates the school’s minor in environmental sustainability. Recently he and his students spent seven weeks digging through the garbage of assorted Portland households. (Relax, it was anonymous – he knows nothing about your dirty, trashy secrets.) We called him up to find out what on earth motivated this effort, what he and his students learned and what, in his opinion, makes the best disgusting garbage.

STARTING POINT: After graduating from the very green Unity College, Wagner turned an internship at the Environmental Protection Agency into a career in environmental policy. “I was in the right place at the right time,” he said. “The cool thing about it is it’s all about human behavior. How do you get someone to take this item and put it over here rather than there?” He holds an advanced degree from the University of Maryland-College Park and did his doctoral work at George Washington University.

As befits an environmental policy professor, he keeps a close eye on recycling efforts around his neighborhood in Portland. “I have always been intrigued by the fact that the city uses those small, open-top recycling totes,” he said. “They have made all these efforts to increase recycling rates, but the volume of the totes hasn’t kept apace.” He’s seen a few too many overflowing bins not to wonder, in this windy little city, whether some materials that are supposed to be recycled are actually contributing to litter on the streets. Or maybe ending up in household trash because the recycling bin was too full. Wagner devised a study to test this theory and see what monetary value, if any, might be lost to the wind/and or the incinerator. It was funded by a grant from the Maine Economic Improvement Fund, administered by USM.

GETTING THE GARBAGE: Did he and the students knock on Portlanders’ doors and say, “Your garbage please?” Technically, he said, once it goes on the sidewalk, it becomes city property, so he could have just whisked it away. But in order to get a better sample, Wagner used a random number generator for city addresses within two diverse neighborhoods, the West End (“urbanized and in some areas very dense”) and Capisic (“which is like 94 percent single-family homes”) and had the garbage collectors set aside the garbage from those locations. “We don’t want to know whose it is,” he said. He didn’t want to offend anyone. Or freak them out. “People are very concerned about privacy in general and yet there is that trusting aspect as they put their trash out in the open.” He and his class of five would drive the route just ahead of the trucks to count containers, calculate the number that had overflowing recycling bins and try to estimate the volume. They did that for six weeks in both areas and then did three “waste characterizations” in each of the two areas. That was the hardest part. “It is probably the most disgusting thing you can imagine,” Wagner said. “It takes a lot of time and a lot of Vicks under the nose.”

DIRTY DETAILS: The sorters divided every bag of trash into 23 categories. They poured the garbage out on two frames Wagner rigged up with chicken wire – the little stuff, like pistachio shells and Q-tips, which there were a lot of, fell right through – and then used barbecue tongs to pick through and separate the remainder. Sorting 300 bags of trash took a team of five roughly seven hours.

QUITE RIPE: Just how old was the garbage when Wagner et al. did their sorting? “It usually took a couple of days to get to it because they (the students) were doing other things,” he said. “And if you are going to do trash classification you need a block of time because you can’t start and stop it,” Wagner said. “By the time we got to the garbage, it was a minimum of three days old. Plus however long people had it around before they put it at the curb. So it was quite ripe.”

GROSS US OUT THE DOOR: Among the notable findings, there wasn’t much green waste (grass clippings, leaves) in what they sorted. The explanation is likely seasonal. “Come September and October we’d see a lot more of that,” Wagner said. The food waste that could have been composted was the most striking. “We saw a lot of unused foods, meat products, remnants that were not cooked. You could also tell when sales were happening.” Like cherries. “A lot of people only ate half of them. A quarter or even a half were not eaten or just tossed out.” (Fools!) Near the end of their collection process, full summer was approaching. “We were just starting to see lobster bodies.” Bummer. That makes good compost. Also, yuck. “Let me tell you, rotting chicken. That was the grossest thing.” He’s still working on the data, but early findings indicate that Portlanders, like most urban dwellers, should be composting more.

ROLE CALL: The students working with Wagner included a sustainable business major and three graduate students from the Muskie School of Public Service. “It’s always easier to get graduate students to do field work like that.” He told himself before the project began to expect to lose a few participants. “Until you have ripped through someone’s garbage you don’t know how disgusting it is going to be.” He was surprised. “Nobody quit,” he said. “But their vocalizations. Their dry heaves. Oof.”