Since 2013, we've been making an ardent effort to implement sustainable practices at the Field and reduce the amount of waste we send to landfill. In conjunction with a strong recycling program, we're committed to composting, with collection bins for organic waste in the Field Bistro, Explorer Café and Siragusa Center, along with containers for employees throughout the non-public floors of the museum. As a result of these programs, we've diverted more than half (53 percent) of our waste from entering landfills for two consecutive years, with compost representing 40 percent in 2016 and 30 percent in 2017.
Why compost? Food scraps are the number one material sent to landfills by weight—more than paper and plastic combined. When food sits in landfills to decompose, it’s trapped by tons of other garbage and emits methane and carbon dioxide as it breaks down. Methane, which is 20 times more potent than carbon dioxide, makes up 10 percent of US greenhouse gas emissions, and 18 percent of that comes from landfills. When organic material is allowed to break down as compost in the presence of oxygen, significantly smaller amounts of methane are produced. Additionally, when they decompose, these scraps create a nutrient-rich material that can be added to gardens to improve soil structure, maintain moisture, and balance the soil’s pH levels.
Though we compost on a commercial scale at the Field Museum, sending organic waste to an off-site windrow facility, you can compost at home on a smaller scale. If you have outdoor space, bin composting (using turning units, stacking bins or bins with flip-tops) will prevent rodents and pests from accessing the scraps. If possible, the bin should be placed on hardscape or with a bottom barrier screen; otherwise, rodents could burrow underneath bins for warmth.
Compostable materials that go into the bin can be divided into two categories: brown and green. Brown material, which is higher in carbon, includes paper, cardboard, dryer lint, dry leaves, twigs, straw, sawdust, eggshells and used potting soil. Green material, which is higher in nitrogen, includes vegetable and fruit scraps, coffee grounds, tea bags and freshly cut grass.
A recipe for (non-smelly) compost
The microorganisms that are responsible for breaking down organics into compost need a certain proportion of carbon for energy and nitrogen for protein production. The fastest way to produce fertile, sweet-smelling compost is to maintain a ratio of generally three parts brown to one part green, broken down into small pieces and in alternating layers. If the mix is too high in carbon, decomposition slows down. If the mix contains excess nitrogen, the pile will emit an unpleasant odor. Every time you add to the pile, turn the material to mix it, either with a pitchfork or a turner in a turn-style bin. When the material at the bottom is dark and rich in color with no recognizable pieces of waste, your compost is ready to use. Spread it on your lawn or garden to help condition the soil and replenish nutrients. Compost should not be used with houseplants because it may contain vegetable and grass seeds that could sprout indoors.
In addition to starting the composting program at the museum, Sustainability Officer Carter O’Brien has his own compost system at home. First, he collects scraps in a small bucket indoors. When the bucket reaches capacity, he transfers the organic matter into a flip-top bin in the backyard. Food scraps (green material) are layered with yard waste (brown material) and thoroughly mixed together. A drawer in the bottom of the bin allows easy access to usable compost.
One thing to keep in mind with a setup like this is that your bin is very unlikely to reach the temperatures needed to break down biodegradable flatware and packaging (a compostable chip bag is still not completely broken down after seven years in Carter’s bin!).
The very hungry earthworm
If you live in a building without access to outdoor space for a compost bin, another option is vermicomposting. This method utilizes a specific species of earthworm known as a red wiggler (Elsenia fetida), which eats its weight in organic matter each day. For this, you will need a covered container with a bedding of dirt, newspaper or leaves. Fruit and vegetable scraps can then be added as food for the worms, which will digest the organic material providing an excellent natural plant food. The Natural Resource Defense Council has a great guide on how to build a worm bin.
If composting won't work for you but you’d like to divert your organic waste from going to the landfill, many local farmers markets offer collection options. Find a Chicago collection location near you.
For additional information on home composting, check out these resources: