Where does garbage really go?

MIT lab develops a tracing microchip

By Tara Ballenger
Globe Correspondent / July 25, 2009

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Early on July 1, a piece of trash was thrown into a garbage bin on Dana Street in Cambridge. It was pickup day, so the trash - a chunk of rubber - was carted away with the other remains of daily life.

But this piece of rubber was different. Inside its urethane casing was a computer chip designed to map its location and send the coordinates back to researchers at the Massachusetts Institute of Technology who are studying where things we throw away actually wind up.

That morning, the rubber was tracked over the Charles River on Massachusetts Avenue, through Back Bay, and then back over the water on the Charlestown Bridge before hitching a ride on Interstate 93 for a 20-mile trek north. It sent its last signal at 12:45 p.m. from an incinerator in Lawrence, where, presumably, it met its fiery end.

The rubber was one of three chunks of trash in the test - chips were also attached to a yogurt cup and a bundle of cardboard. The yogurt cup, logically enough, wound up at a recycling factory.

But garbage doesn’t always land at its intended resting place. The destiny of the cardboard, for example, remains a mystery. The last researchers heard from its tracking device, it was sending a signal from a South Boston parking lot.

The tracking devices - called smart tags - will make their prime-time debut next month in Seattle, where thousands of volunteers will attach the tags to trash selected by the researchers and then discard the rubbish as they normally would. Smaller launches will take place in New York City and London, and the voyage of each item will be recorded.

Scientists from MIT’s SENSEable City Laboratory, a research team that uses sensors and other technology to analyze cities in new ways, hope that tracking the trash through the disposal system - and making it viewable in real time on a blog - will cause consumers to give more thought to what they are tossing out. They also want to answer a question dear to the hearts of recyclers: Do the soda cans, pickle jars, and old newspapers placed in recycling bins arrive at their intended destinations or take unexpected detours?

The tag is small, waterproof, and nearly indestructible, meaning it can be attached to everything from water bottles to pizza boxes and survive its journey. Using cellphone towers, the devices send information about their locations back to MIT computer servers that map the coordinates in real time.

“When you throw something in the trash, most people think it’s gone. It just disappears,’’ said Assaf Biderman, associate director of the SENSEable City Laboratory. “What would happen if you knew what happened to the plastic cup you threw in the garbage three days earlier?’’

The group chose Seattle for its big-time rollout because of the city’s reputation for recycling - it recycled half of its residential and commercial waste last year. Seattle’s sophisticated recycling system made it ideal for the tracking system because there are so many different waste streams that can be evaluated. Biderman wants to know, for instance, how much of the waste placed in recycling bins arrives at the appropriate facility.

Cities with far less sophisticated waste disposal systems - including Boston - were not considered good candidates for the trial. Boston’s system is not nearly as advanced as Seattle’s: Fifteen percent of waste gets recycled in the Hub, less than half the national average.

Because of state budget cuts, there’s less money to educate consumers on the specifics of where and how to recycle and that, in turn, has translated into continued low recycling rates, said Ann Dorfman, vice president of MassRecycle, a coalition committed to increasing recycling. And even people who want to recycle sometimes can’t - because there’s just no blue bin in their favorite restaurant to take their used soft drink bottle.

“People are really starting to feeling uncomfortable with not recycling their trash, but some business and public spaces haven’t caught up,’’ Dorfman said.

The lab is continuously improving its tags, making them smaller and smaller. The “tester’’ trash sent out earlier this month in the Boston area carried tags the size of matchboxes. By the main deployment in August, Biderman said he hopes the tags will be the size of a cellphone’s SIM card.

And because the journey can be long and arduous, the tags are built to last. They will send out signals for up to two months and are designed to withstand intense pressure. Biderman said tags survived water immersion and blows by a hammer during lab tests.

“Sensors and electronic devices are becoming less and less expensive, so we thought that we should use them to address one of today’s most pressing problems - waste - and try to understand better what we could call the ‘removal chain,’ ’’ said Carlo Ratti, director of the SENSEable City Laboratory. The lab has used sensors to trace things like the flow of people in Copenhagen’s club scene and the use of public transportation in Rome.

In addition to being posted on the blog, information gathered from the Seattle launch will be presented at an exhibit in the fittingly ultra-modern Seattle Public Library in September, as well as at an Architectural League exhibit in New York City the same month.

The project will cost $300,000 for the development and deployment of the tags and is being funded internally now, but outside sponsors may be announced later.

The information will also be used to detect inefficiencies in the waste removal system. SENSEable City Laboratory partnered with Seattle Public Utilities and one of its main contractors, Waste Management, to share information.

Brett Stav, senior planning and development specialist for Seattle Public Utilities, is interested in finding out how long trash routes take to complete and whether residents are taking advantage of special programs to recycle things like electronics and motor oil.

“Anytime we can find inefficiencies and improve them,’’ Stav said, “it’s a good thing.’’