Trash stuffed in recycling bins is actually being recycled, according to a group of MIT researchers who have been tagging and tracking certain recyclables since 2009. Discarded electronics and household hazardous waste is also making it to recycling centers, though its journey can be surprisingly long.
Though refuse collection and processing companies keep records of their operations, no one seemed to have any idea of the route taken by trash from garbage bin to its final destination, according to researchers at MIT’s SENSEable City Lab.
The team dubbed its project “Trash Track” and told the CNET website that it was “designed to monitor trash from start to finish.” The team, led by Carlo Ratti, director of SENSEable City Lab, would “electronically tag different pieces of waste to trace their voyage through the disposal systems.”
The objective of the project was to “reveal the disposal process of our everyday objects, as well as highlight potential inefficiencies in today’s recycling and sanitation systems,” Ratti explained. The project website asks visitors to imagine “a future where we understand the ‘removal-chain’ as we do the ‘supply-chain’.”
Follow That Trash.
Ratti’s team spent most of 2009 “attaching thousands of tracking devices to pieces of garbage in Seattle and New York City,” which sent out location pulse signals to the SENSEable City Lab and to “exhibits in both cities, where live maps revealed the many paths garbage takes,” Scientific American reported in 2010.
Dietmar Offenhuber, a doctoral student at the lab, told Scientific American that part of the rationale for conducting the study was to determine if the millions of dollars being spent on recycling programs were being spent well. Some question whether recycling creates more greenhouse gases than it conserves or wastes more energy than it saves.
Nobody Really Has The Overall Picture.
“Even the people working in waste removal don’t really have a clear knowledge or picture of where the stuff goes,” given how many handoffs trash companies make, Offenhuber said.
The team initially used tags equipped with GSM cellular phone technology to estimate the position of the trash by “measuring signal strength from each cell tower in sight of the device and comparing it to a map of cell phone towers,” project members explained — standard triangulation. The researchers tagged about 3,000 items of garbage in Seattle alone.
They soon switched to tags using GPS and CDMA cell-tower trilateration “based on the Qualcomm inGeo platform… in combination with Sprint’s cell phone network, using Qualcomm’s gpsOne technology to provide both accuracy and availability for position tracking applications.” And as they were going to be tracking over weeks and months to find final destinations, the team developed “duty cycling algorithms,” to get hibernation capability “that keep the tag off most of the time, turning it on only every few hours to sense and report its position.” The device switches off if no movement is detected to prolong battery life.
Extensive and Complicated Network Uncovered.
The “extent and complexity” of the network handling waste in the United States surprised researchers, Offenhuber said.
Another surprise was how far some waste traveled. Electronic and household hazardous waste from Seattle, much of which had to be sent to specialized treatment facilities, “traveled on average more than 932 miles.”
One printer cartridge had an odyssey of 3,823 miles — a prodigious use of resources and energy to recycle a printer cartridge, the researchers said. Offenhuber said that telephones and printer cartridges also get shipped across the country — to Chicago, Miami, and New York.
Preliminary reports indicate that about 75 percent of the waste from Seattle that was tagged actually reached recycling facilities, which project officials called “significantly above the U.S. average,” with 95 percent of the trash reaching “EPA-compliant end destinations in the vicinity of the Seattle metropolitan area.”
That’s Some Journey.
Yet as the journeys of some of the trash might indicate, there’s a trade-off between recycling and “the carbon emissions produced in getting waste to a recycling facility,” which project officials speculated could negate “the expected benefits of recycling.”
“Because the recycling process itself generates, of course, an environmental burden, this burden is also depending on the transportation distance,” Offenhuber told Scientific American. “So if you have an object that yields very little energy in the recycling process, and you have to carry it through the whole country, then you have probably a higher environmental burden than gain.”
The team wrote in a paper published soon after the project that its results show that electronic and household hazardous waste items travel significantly longer and more arbitrary trajectories than other types. “We show how existing models for waste emissions, such as the Environmental Protection Agency’s Waste Reduction Model, may underestimate the environmental impact of transportation by not accounting for very long trajectories that include multiple transport modalities,” they wrote.
However, for standard curbside recycling and landfilling, “the environmental impact of transportation distance seems to play a minor role… the expected transportation distances do not significantly differ whether the item was discarded in an urban, suburban, or rural setting (although the setting seems to have some influence on the duration of the waste removal process),” the team wrote.
Ratti, Offenhuber, and Malima I. Wolf plan to publish a summary of the project’s findings as “Trash Track – Active Location Sensing for Evaluating E-waste Transportation,” in an upcoming edition of Waste Management & Research.