Food scraps revisited
Toolbox
By JUNE VAN HOUTEN Herald Correspondent - Published: October 25, 2009
Disgusting, stinky, slimy!" These were just a few of the comments from students in a recent training program about composting at Bellows Free Academy in St. Albans. Their reaction was not aimed at piles of oozing food waste, but instead at the effects of toxic algae blooms in Lake Champlain's St. Albans Bay, a popular swimming spot for locals. These trainings are occurring all around the state, but in St. Albans the message hit home in a powerful way. While composting food scraps won't directly clean up the lake, improving soil quality — a major goal of these programs — is very much part of the solution.
"If a tree dies in the forest does it get put it in a truck, driven to the landfill and dumped out?" "No," said the chorus of students. There is no waste in nature. The fallen tree decomposes into soil that will serve to nurture a sapling.
This closed loop system is the model for our programs at the Highfields Center for Composting in Hardwick. In partnership with solid waste districts, we work with communities to collect food scraps from schools and businesses and haul them to a local farm for composting. The compost produced is used to fertilize fields and grow more food to be sold back to the community, thereby closing the loop on the food system.
What does this have to do with Lake Champlain? In St. Albans we talked with students about Vermont's watershed. From snowmelt on Mt. Mansfield to rain on farm fields, water from many sources eventually runs into rivers that feed the lake. High phosphorus levels in the lake drives algae blooms that make swimming in St. Alban's Bay and other local beaches decidedly unappealing at times.
The primary sources of lake water phosphorus are the synthetic fertilizer and liquid manure applied to farm fields throughout the state. Most of the phosphorus is not water-soluble, so it piggybacks on soil particles.
Liquid manure also gives plants an intense shot of nitrogen — more nitrogen than the plants can use — and much of it runs off with the phosphorus. And these highly soluble forms of nitrogen do not provide adequate organic matter to prevent erosion. Soil compaction from heavy farm equipment exacerbates and accelerates the loss of nutrient-rich topsoil. When soil is compacted, rain can't percolate into it. Instead the rain runs off and takes agrochemicals and topsoil with it. High phosphorus in streams is an indicator that we are losing valuable topsoil. Basically it means that we are turning our topsoil into a parking lot and treating it like dirt.
When compost is used on farm fields the nutrients are released more slowly compared to synthetic fertilizer, and so they are more available for the plants to take up. Compost also acts like glue. It holds the soil in place and prevents runoff and so protects against the loss of valuable topsoil keeps streams from nutrient loading. Healthy soils, able to absorb and retain more rainwater, provide drought-resistance to crops. Compost is truly alive — and that microbial life is necessary for building healthy soils.
Beyond building healthy soils and maintaining healthy watersheds, diverting food scraps from landfills for composting has additional benefits. Food scraps may seem relatively benign compared to other ingredients in our trash, but in reality the food scraps in landfills release methane and nitrous oxide — greenhouse gases many times more powerful than carbon dioxide.
On a trip to the Coventry landfill I saw a "cell" that was 8 acres wide and 40 feet deep. Trash collected from around the state had filled it to road level in six months. (The landfill is developed from these cells, which are giant holes that are dug, lined and then packed with waste.)
The Coventry landfill does generate power from methane released. But this is a very inefficient way to generate power from food scraps. There are more efficient digester systems that can be used to generate power from methane released from food scraps.
Food scraps make up about 30 percent of the waste stream. Composting food scraps would double the state's recycling rates and reduce dependence on landfills. Our goal at Highfields Center for Composting is develop the necessary infrastructure to divert 100 percent of food scraps from landfills for agricultural use by 2017.
A carbon emissions study conducted by Highfields showed that composting all the of food scraps in Vermont instead landfilling them would reduce carbon emissions equivalent to not burning 12 million gallons of gasoline annually. This conservative estimate gave the landfill credit for capturing 100 percent of the methane. The big savings would actually come from reducing the use of synthetic fertilizers and replacing them with compost. The point of composting, an aerobic (with oxygen) process, is to utilize the nutrients found in decomposed food scraps for crop fertilization and soil improvement, and not let them volatize (be released as gases) as they do in landfills.
With this in mind we reconsider that tree decomposing in the forest and then look at the landfill and realize that there is a better way to go. Before cheap fossil fuels made petroleum-based fertilizers affordable (natural gas is used to make about 97 percent of the fertilizer applied to crops in the United States), food scraps were considered a valuable resource as both animal feed and compost for building healthy soils. The 130,000 tons of food scraps sent to Vermont landfills each year, once composted, could meet the fertility needs of an estimated 17,000 acres of mixed vegetables.
With so many events in the world today beyond our control, these statewide composting programs offer a valuable opportunity for students to make a significant local impact in their local communities. Such programs give us all a simple thing we can do every day to be part of the solution — throw your leftover food into the compost bucket instead of the trash and close the loop on the food system.
We are all upstream on our state's diverse watersheds, and our actions directly affect these fragile ecosystems. The choices we make daily will eventually impact our personal health, the well-being of marine life, and the summer fun of the children in St. Albans and all of us who love Lake Champlain. Close the loop.
June Van Houten is the director of marketing and development at Highfields Center for Composting and lives with her family in Calais. She can be contacted at june@highfieldsinstitute.org
ON THE NET
Close the loop on your community's food system. Visit www.highfieldsinstitute.org
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