Enter Bennett Composting...
Composting in Philadelphia has not always been so easy. This is what inspired Tim Bennett of Bennett Compost to start his own company to help make Philadelphia a greener city.
Ten years ago while living in a second-floor apartment in South Philly, Tim Bennett struggled to find a facility that would compost his food waste. He quickly discovered that there were no on-site composting site for city residents. This may discourage most folks, but not Tim.
With $100 in the bank, Tim started Bennett Compost. Fast forward to today, Bennett Compost proudly serves 3,200 households and 85 commercial businesses in Philadelphia. Three co-owners employ 8 full-time and 4 part-time people. Compost is picked up in the region by bicycle (in dense areas) or light trucks and is taken to Saul High School or a farm in Montgomery County, PA Royersford or processing themselves.
Tim Bennett, founder of Bennett Compost, at a composting presentation to Mt. Airy Nexus, Philadelphia.
During a lunch-n-learn visit to Mt. Airy Nexus co-working space, Tim explained the composting process. With just the right mix of “browns” (dry, woody plant material which provides carbon) and “greens” (wet, food scraps that are high in nitrogen), the organic matter quickly breaks down. When compost piles reach internal temperatures of 135degrees F, it’s hot enough to break down any invasive weeds or seeds.
Residential customers participate in once a week collection of their organic matter of fruits, vegetables, coffee grounds, newspapers, paper towels -- no meats or dairy products. Commercial customers can compost just about any food scraps, including meat and dairy.
Composting and Climate Change
If you want to reduce your contribution towards climate change impacts, composting is a good place to start. Not only does composting reduce the amount of waste ending up in landfills, it also produces less heat trapping gases than landfills (Lou and Nair, 2009).
To illustrate this, consider an apple that will eventually end up in a compost pile. The apple tree absorbs atmospheric carbon dioxide and produces oxygen. The carbon that this apple tree took out of the atmosphere is then stored, or sequestered, in different parts of the tree: leaves, wood, and apples. The apple (with its stored carbon) is then picked, sent to a store, then purchased and eaten. The apple core ends up in a compost bucket and taken to a composting site by people like Tim Bennett. There, the apple will start to decompose.
During the aerobic decomposition process, little microbes will “eat” the organic matter in the compost pile. These microbes, like humans, breathe in oxygen and breathe out carbon dioxide. The carbon in the carbon dioxide they respire comes from the apple core they just ate. This breathed out carbon dioxide is what scientists detect when measuring how much carbon dioxide comes from compost. However, because the carbon dioxide being breathed out into the atmosphere by the microbes is the same carbon dioxide that the apple tree absorbed and stored in the apple, there is a net zero effect on carbon dioxide levels in the atmosphere.
Diagram of carbon cycling in compost. 1) The apple tree takes in carbon dioxide (CO2), and “breathes out” oxygen (O2). The tree stores the CO2 in the leaves, bark, and apples. 2) The apple is eaten, put in the compost bucket, and then taken to a compost site where it is added to a compost pile. 3) In the compost pile, microorganisms take the carbon (C) that’s been stored in the apple and oxygen from the air and breathe it out as CO2. Since this is the same CO2 taken in by the apple tree in Step 1, so no extra CO2 is added to the air.
Unlike compost, conventional landfills produce large amounts of methane in addition to carbon dioxide. Scientists tend to ignore the carbon dioxide that comes from landfills because, similarly to compost, it also has a net zero effect on atmospheric carbon dioxide levels.
Methane, on the other hand, is a different issue. Conventional landfills use anaerobic decomposition, or decomposition in the absence of air. Because of differences in the decomposition process for landfills and compost sites, methane occurs as a by-product much more frequently in landfills than in composting sites (Lou and Nair, 2009). Methane is especially problematic because it has a global warming potential that is 28-36 times as great as carbon dioxide -- causing significantly more warming during its lifetime in the atmosphere than carbon dioxide does (EPA).
Unlike landfills, studies have found that compost produces almost no methane. The only significant heat trapping gas produced from compost is carbon dioxide, and as mentioned earlier, carbon dioxide has a net zero effect on the climate (Lou and Nair, 2009).
Talking the Talk, and Walking the Walk
At Mt. Airy Nexus, where our story began, composting is a part of everyday life. A bright green composting bin with a carbon odor filter can be found in the kitchen where members can dump their leftover mac and cheese, apple cores, coffee grounds, and much more. Bennett Compost collects the bin every week, helping Mt. Airy Nexus to provide an environmentally conscious co-working space. At Mt. Airy Nexus, they don’t just talk the talk, they also walk the walk.
When asked about how she perceives Mt. Airy Nexus members’ experience with composting, Community Manager Sonni Schwartzbach said “Most of our members are connected to environmental sustainability through the work they do, and composting is one way that we can support this mission.”
Sonni Schwartzbach, Community Manager of Mt. Airy Nexus, using the office kitchen compost bin. Every week, Bennett Composting collects the contents and takes them to a composting site to be turned into soil.
For more information about composting, visit Bennett Compost’s website.
By Mahvish Ilyas and Allison Day. Mahvish Ilyas is a graduate of the University of Pennsylvania with a Master of Environmental Studies in Environmental Policy, Management & Business, and is currently working as the Solar Projects Coordinator with Philadelphia Energy Authority. Allison Day is a recent graduate of the University of Pennsylvania with a Bachelor of Arts in Environmental Studies and an intern with Boyer Sudduth Environmental Consultants.
