Overall, the Boston mayoral candidates agree with the city’s goal to cut greenhouse gas emissions. Several have mentioned that they want to see improvement in Boston’s recycling rate, which, at 20 percent, is 10 percent lower than the national average. But to match recycling rates of 80 percent in San Francisco, 65 percent in Los Angeles, or 55.7 percent in Seattle (a city comparable to our own size), we need to go a lot further than the suggestion of John Connolly and Felix Arroyo to add more recycling bins on streets and in parks or Charlotte Golar Richie’s idea of recycling competitions.
San Francisco’s high rate of diversion of waste from landfills is partly because the city has been collecting organic waste at curbside along with regular recycling since 1996. Organic waste, which includes food scraps, yard clippings, pizza boxes, paper, and paperboard, comprises 56 percent of the waste stream nationally. Once buried in a landfill, it produces methane — a greenhouse gas that is 20 times more potent than carbon dioxide, even though it stays in the atmosphere a shorter time. Food waste in Boston comprises 20 to 25 percent of the current waste stream (not including paper and paperboard), so recycling it would put us in line with other leading cities.
Organic waste is recycled through industrial scale composting or anaerobic digestion, the latter of which is supported by all the candidates who answered environmental questions posed by the Globe. Anaerobic digestion captures reusable biogas by breaking down bacteria in an oxygen-free environment. The resulting product, which is 60 to 70 percent methane and 30 to 40 percent carbon dioxide plus trace elements, can be used for fuel in many types of applications. Manure from agricultural sources is often used in digester projects, and organic waste from households and commercial enterprises could meet more of our region’s power needs through diverted waste materials.
San Francisco is on target to achieve zero waste by its 2020 goal, and Los Angeles is not far behind. The successes in both cities are driven by state legislation. Assembly Bill 341 expands on earlier legislation by increasing California’s waste diversion goal from 50 percent (which it surpassed in 2000 by 8 percentage points) to 75 percent by 2020.
It’s not just a California thing. Florida passed similar legislation in 2008 that requires a 75 percent waste reduction target by 2020.
Massachusetts is moving in this direction, but slowly. The Massachusetts Commercial Food Waste Bill requires commercial institutions that produce more than 1 ton of organic waste a week to divert it from landfills starting in July 2014. This is a good start, but we need to follow the more ambitious paths of California and Florida.
More than 100 cities have curbside collection of organic waste, but Boston only has a voluntary program through which residents can pack up their organic waste for collection at farmers’ markets and a voluntary supermarket organics recycling program. To go to curbside pickup, we need more recycling capacity. The only industrial scale composter in Massachusetts is in Marlborough, and it is running at full capacity.
The anaerobic digester at Deer Island has plenty of capacity, but cannot handle residential organics. To change that, the Massachusetts Water Reclamation District has solicited a request for proposals for a pilot project to pretreat organic waste so it can be pumped into the Deer Island digester. This pilot could move us in the direction of organics recycling. Still, Boston needs to take bolder steps.
We have a chicken-and-egg problem. Boston cannot begin a massive organic waste diversion program until there is capacity to process it. And no company will build a new digester without a guarantee of volume. Boston could follow the path of other cities by issuing a competitive bid for its organic waste stream. The companies bidding would give their best disposal price per ton for a 20-year period. Even better, Boston could offer to purchase the renewable power from any such facility. It’s time to make the first move.
Recycling is the low-hanging fruit of urban sustainability. For a city just named the most energy efficient in the nation, we shouldn’t settle for being in the bottom third.
Joan Fitzgerald is interim dean of the School of Public Policy and Urban Affairs at Northeastern University.