Used to be you took out the trash. But if Boston officials have their way, the trash will soon be coming in—at least some of it, that is.
City officials hope to use this trash to produce enough energy to power about 1,500 homes.
It’s all part of an innovative new initiative to create an indoor composting center that would help slash green-house gas emissions from the decaying pile of discarded food and yard-cuttings that comprise Beantown’s outdoor, 6,000-ton composting program. The new facility would allow officials to separate out the high-energy components in the pile and feed them into an anaerobic digester, where they would be converted to methane gas. This biofuel would then be used to power a turbine that could generate 1.5 megawatts of power. Not bad for a pile of garbage!
In Boston (and around the country) outdoor composting programs allow significant amounts of potential energy to escape. And in colder climes, they don’t work effectively year-round.
“When you’re composting outdoors in a four-season place like Boston, during the wintertime there’s not a lot going down,” says Bryan Glascock, director of the environment for the city of Boston.
That’s because the temperature of the large compost pile needs to be high so that microbes can break down organic matter. Indoor facilities solve the problem by providing warm temperatures year-round.
That’s not the only advantage of moving the program indoors. It also would allow the city to process material more quickly and to develop a more uniform compost product.
In addition, some of the gas coming off the heap could be used to heat the building itself, and, potentially, could be made available to nearby facilities in a district heating-and-cooling arrangement. Shifting the composting program indoors would also cut down on odor and runoff –two constant problems for composting facilities.
“If you pile all your leaves in a big pile, that’s great,” Glascock says. “But there are a lot of other things you can have going on that really maximize that microbial action.”
Currently, trucks remove chunks from the mound and feed them into a grinder. In about a year, the resulting mulch is ready for use in community gardens and by private gardeners, who can purchase it for $22 a yard.
In the new indoor center—still very much in the planning stages—heat and biogas released as plant and food matter decays would be recycled, and carbon dioxide would foster the growth of plants in a greenhouse that would be built on the center’s roof.
Boston has put out a “request for expressions of interest” to determine which companies are familiar with the process and interested in working with the city. The public bidding process is expected to be competitive.
And not long after that, Glascock and other city officials hope that when Boston residents are asked to take their trash in, they won’t bat an eye.
