From Garbage to Gold

by Organic Gardening staff

From the window of his second-floor office deep in the heart of the Intervale, Adam Sherman can see nothing but other people’s garbage. He considers it the best view in town.

Sherman is the organic cooperative’s king of compost. As manager of Intervale Compost, he is in charge of turning 12,000 tons of raw waste a year into 6,000 tons of fine-textured finished compost. In 1999 this “black gold” brought in $450,000 in revenue against $375,000 in expenses. The compost is snapped up in bulk by farmers, landscapers, and golf courses, and in 5-gallon bags, at $2.49 each, by backyard gardeners. It is the nonprofit The Intervale’s biggest moneymaker. Sellouts are common. “We can’t keep up with demand,” Sherman says. “We’re turning people away. They’re heartbroken.”

Sherman and his band of merry composters gleefully violate the sacred rule of backyard composting: no meats, breads, or dairy products. Intervale Compost not only accepts food garbage from restaurants and food services around Burlington; it encourages the practice by charging lower dumping fees than those imposed by local waste-transfer stations. It hauls in tons of litter from animal stables and accepts 1 million gallons of Ben & Jerry’s ice-cream residuals a year. The dairy waste, which has the consistency of a milkshake, is brought in as often as twice daily in giant tanker trucks and sprayed on the windrows. How is this done without creating a big stink and drawing vermin? The secret is in the mix.

Food garbage is carefully blended with vast quantities of bulky dry materials, such as sawdust and leaves. The 400-foot-long windrows soon heat to a steamy 140_F, even in Vermont’s bitter winters, and any odors quickly burn off. The piles are turned frequently with large machines to keep air circulating. “As long as we’re mixing it at the right recipe, it will continue to cook,” Sherman says.

Analysis of Intervale Compost
(percent by dry weight)
Organic matter: 26-30
Nitrogen: 0.77
Phosphorus: 0.24
Potassium: 0.30

The composting process takes 9 months, and the finished product is balanced between acidity and alkalinity, with a pH level of 7.2. Sherman picks up a handful of the finished, screened compost and lets it crumble through his fingers. “Like a fine wine,” he says fondly, “it only gets better with time.”

Reprinted with permission from Organic Gardening Magazine

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