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Tech

How to Turn Compost into Cash

A tour of Recology's composting facility shows how waste can be saved from landfills to make an in-demand product.
Image: Max Cherney

The first thing I think of when I hear the word compost is the smell. And it’s not good. Sometimes when I take my San Francisco apartment’s compost to the building’s larger container I nearly ralf, it’s that pungent. But, being an adult, the second thing I think of is that it’s the smell of the future—and some entrepreneurial genius will eliminate the odor sooner or later (we all hope). That’s because more likely than not we’re all going to have to start composting.

If you’re not too familiar with composting on an industrial-scale, that wouldn’t be much of a surprise. While the number of municipalities and states that do so is growing, there remains a startling amount of organic waste that ends up in landfills—which, in the long run, isn’t a great plan. Among other forms of environmental damage, landfills emit large amounts of methane (which includes CO2) into the atmosphere, and contribute to global warming.

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The idea behind composting city, state, or country-wide is basically to reduce the amount of municipal solid waste—otherwise known as garbage—that ends up in landfills, and transform it into something that’s useful and doesn’t damage the environment.

So when San Francisco-based Recology, a company long-known for its innovation in composting practices and technologies, offered to show me around their facility near Vacaville, California, I jumped at the chance. Because these guys have figured out how to turn that foul-smelling compost into cash.

The reason Recology has been able to transform waste into checks is simple: Farmers have found compost-based fertilizer to be far more effective than industrial, chemical fertilizers at giving soil used for agriculture much-needed nutrients. Those nutrients in turn produce healthier yields, said Nigel Walker, a farmer in California’s Central Valley. They also sell about 25 percent of the final product to landscaping companies. Right now, Recology can’t produce enough compost to meet the demand from farmers, company spokesman Robert Reed said.

Recology plant manager Greg Pryor (center) leads a staff meeting. Image: Max Cherney

The scent at the Jepson Prairie composting facility is hard to describe; duller than the stench emanating from my apartment building’s compost bin, but fairly pungent nonetheless. “It used to be a lot worse,” Greg Pryor, the plant manager, told me, adding that the company has developed ways to reduce the odor over the years. He said that he used to have to change out of his work outfit in the garage, or else risk his wife’s ire.

Pryor has been in the business for 20 years and has personally developed some of the critical aspects of the methods Recology uses to transform what goes into Bay Area compost bins—he’s like their Wayne Gretzky of engineers, and he showed me around.

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The facility itself is sprawling, totaling 56 acres (22 of which are actively producing compost). It can process about 600 tons of compost every day, and there was a fleet of heavy construction equipment and trucks hauling compost scurrying around the site. Once in a while a military aircraft would roar by overhead, as Travis Air Force Base is located a few miles away.

They even had a some chickens on site, which were supposed to help deal with ever-circling birds. “The girls feed them too much, so they’re not really motivated to fight the gulls for food,” Pryor told me. The state of California actually counts the number of birds that hang around waste disposal sides since they often carry diseases. Though the chickens didn’t work out—Recology has found other methods to get rid of the gulls—Pryor told me it's still cool to have fresh eggs all the time.

Image: Max Cherney

Producing such desirable fertilizer isn’t as simple as throwing a bunch of food scraps and yard waste into a big pile and waiting until it turns into money. Basically, the process works like this: Compostable material is collected by the company’s trucks—think yard debris like leaves or food scraps from homes and restaurants—and transported to the Jepson facility. There, it goes through a process to reduce its size, using a propriety mix of screens and grinders that also sort out objects that won’t break down during the process.

Next, the blend is arranged in piles and taken through three aeration zones for 10 days at a time. Forced aeration is kind of like a giant vacuum sucking air from the bottom through the piles. The air is needed to feed the anaerobic microbes and sucking it through the piles ensures that the center receives just as much oxygen as the outside.

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What I thought was cool—and isn’t apparent from the photographs—was that the piles of compost are hot to the touch, and run about 140 to 170 degrees Fahrenheit in the center. The heat is a byproduct of the biological activity, and the steam coming off the top is from the moisture inside.

After exactly 30 days “on air,” the compost is moved into windrows. Once there, it's “turned” by a roto-tiller type machine every day, and moisture is added. Pryor told me that in Recology’s process the windrows serve to set the compost, by stabilizing and curing the organic materials. Many other compost facilities in the country only use windrows and skip the aeration step.

Another 15 to 30 days later the compost is filtered through a giant sieve that turns at about 20-25 RPM, and prevents organic chunks over about 1/2 to 3/4 of an inch from making it through—anything that’s too big is re-processed in the hopes that it will break down.

Image: Max Cherney

The final step Recology performs is blending the compost with other materials their agricultural clients have asked for. The company does so because different soils and crops require different ingredients to get the most out of the land. Additives can mean any number of things; crab and oyster shells, chicken meal, and even lime—each additive carries a unique quantity of minerals and chemicals.

Recology sells the final product for between $7-10 per cubic yard (it’s not done by weight because it would be easy to artificially jack the price up by dampening the compost, for example). California farmers can’t get enough of the custom blends, Pryor told me, but the main hurdle to producing more fertilizer is the entrenched garbage and landfill business. According to company spokesman Reed, that’s because garbage and landfill businesses have made it very difficult for Recology and its competitors to expand their business.

The economics also need to make sense. To put it plainly: composting can be expensive, and landfills are cheap, so the compost industry has had to ensure that hauling organic waste is cost-competitive with regular garbage. That’s about $20-30 per ton, which Reed proudly said Recology was able to match.

These hurdles haven’t stopped Recology from expanding its business into Oregon and Nevada, to a total of eight compost processing facilities. And the city of San Francisco has announced that the city aims to divert all of its waste from landfills by 2020, something that will help Recology and others in the business prove the concept. The rest of the state and country is another story. While there are many other promising developments, it’s clear the US—including California—has a long way to go before composting is regarded as a necessary future, not some gross thing San Franciscans do.