An Elegant Matrix

Woody waste finds new markets in biochar
0352_OSUMkt_1581

Reaching temperatures as high as 700 degrees Celsius, John Miedema’s hand-crafted furnace turns woody wastes into biochars that are bring tested at Oregon State. (Photo: Karl Maasdam)

This story begins with an entrepreneur – a citizen scientist living in the timber town of Philomath, an outdoorsman, fisherman and organic farmer of Dutch and Blackfeet ancestry who’s hell-bent on healing an ailing Earth. A few years ago, his longtime quest for planetary remedies began to take form as a towering furnace built with castoff parts and a gasifier once owned by a Y2K doomsday cult. The 20-foot-tall furnace looks more like a tinker’s collection of rusty metal than an invention for the future of the planet. But in this Rube Goldberg contraption, John Miedema is turning forest and farm waste into promising new products – products that could help revive rural Oregon economies, keep contaminants out of rivers, store carbon in soils, and even save the fragile peat bogs of Canada.

To push that vision, he is collaborating with scientists and students just over the hill at Oregon State University – researchers with expertise in subjects ranging from horticulture and engineering to forestry, hydrology, soil science and natural resources. Together, the university researchers and the dogged entrepreneur are studying “biochar,” woody waste (such as tree bark or nutshells) that has been heated at very high temperatures in an oxygen-free furnace like the one Miedema built. Scientists call the process “pyrolysis.”

0005_OSUMkt_1581

Woody wastes such as tree bark and filbert shells retain their underlying structures during pyrolysis. Higher heat creates more nanopores. (Photo: Karl Maasdam)

In essence, biochars are chunks or shards of solidified carbon full of tiny air pockets. Besides locking up carbon that would otherwise contribute to greenhouse gasses, they can serve as containers to hold beneficial things added to soils (like water and microbes) or remove harmful things from storm water and industrial sites (like heavy metals and other toxins). As a bonus, energy generated during the conversion can be captured and used onsite.

In the Northwest, where tons of biomass rots in forests or burns in slash piles, the conversion of waste into clean energy and marketable products is an environmental and economic win-win.

Heavy Metal

Miedema unscrews a giant mason jar and tips it up, pouring a pile of shiny black chunks into his hand. With the naked eye, it looks like the remnants of a campfire. But a closer view reveals the properties that have inspired a big biochar buzz across the Pacific Northwest and around the world. Under a powerful microscope, biochar sometimes resembles a honeycomb, other times bubble wrap or a sea sponge. Its internal structure differs, depending on whether it started out as Douglas fir bark, hazelnut shells, corncobs or some other “feedstock.” Temperature, too, alters its structure, contributing to biochar’s astounding porosity. Its millions of micro- and nano-pores form “an elegant matrix,” in the words of OSU forestry instructor David Smith, whose students have investigated storm water filtration markets for biochar.

“If you look under an electron microscope, what you see is the inherent structure of the plant – all the cell walls and all these internal galleries,” says Miedema, who founded the Pacific Northwest Biochar Initiative in 2009 – a “brain trust” of academics, researchers, engineers, foresters, farmers, policy experts and business leaders interested in moving biochar forward in the region.

Those “internal galleries” can take up and hold enormous amounts of water as well as minerals, nutrients, microbes and pollutants. Oregon State researchers are studying ways to make practical use of this super-porosity by creating “designer chars” – chars that are “artfully prepared” with special properties aimed at specific uses.

Heather Stoven cut, dry and weigh marigolds grown in mixtures with varying proportions of biochar. (Photo: Frank Miller)

Working with graduate student Myles Gray, Heather Stoven cuts, dries and weighs marigolds grown in mixtures with varying proportions of biochar. (Photo: Frank Miller)

One of those uses is environmental cleanup. Biochar can absorb pollutants in storm water before dangerous metals like zinc (from roofs) and copper (from brake pads) flow into streams and rivers. “Copper is particularly troublesome because it’s been shown to be toxic to juvenile salmon,” says OSU’s Jeff Nason, a professor in Chemical, Biological and Environmental Engineering. “These are Endangered Species Act types of considerations.” Nason, who works with the Oregon Department of Transportation on ways to remove copper from storm water, is looking into biochar. His lab has hooked up with Miedema to begin testing char as a “low-cost alternative” to more expensive materials such as activated carbon. Cities, too, are taking notice. Corvallis, for instance, is experimenting with biochars in bioswales, which are shallow hollows in urban landscapes designed to capture and filter storm water.

At Oregon State's Extension center in Aurora, researchers are testing biochar's potential as a planting medium to replace peat moss. (Photo: Frank Miller)

At Oregon State’s Extension center in Aurora, researchers are testing biochar’s potential as a planting medium to replace peat moss. (Photo: Frank Miller)

Another use for biochar is in potting mixes. With funding from the national Sun Grant Initiative, Professor Markus Kleber in Crop and Soil Science is testing various biochars for their potential to replace peat moss as a potting medium in the greenhouse and nursery industry, Oregon’s top agricultural sector with sales of nearly $700 million. Peat, harvested from pristine bogs in Canada, the British Isles, Russia and other northern climes, is costly both in dollars and environmental damage. Biochars promise a cheaper, local alternative, says Kleber. He and his graduate student Myles Gray have analyzed the water-holding capacity of chars made of Doug fir (more porous) and filbert nuts (less porous) that have been heated to temperatures ranging from 300 to 700 degrees Celsius. They found that higher-temperature chars have more surface area and therefore hold more water.

Also, with funding from the OSU Agricultural Research Foundation, Kleber is designing a biochar to substitute for another horticultural standby, vermiculite, which is mined overseas and requires high-energy inputs during processing. “Vermiculite puts heavy loads on the environment,” says Kleber. Finally, researcher John Lambrinos in horticulture is investigating biochar as a lightweight water-retention medium for green roofs.

Something Fishy

The grandson of a Dutch dairy farmer, John Miedema saw his favorite childhood fishing holes in Marysville, Washington, gradually turn green and gunky as the herd where his grandad worked grew from 50 head to 500. The blighted streams bothered him enough as a young man that he abandoned dairy farming and went to sea, purse-seining for salmon, long-lining for black cod and halibut. On the boat, he read a lot – Buckminster Fuller’s Operating Manual for Spaceship Earth, E.F. Schumacher’s Small is Beautiful. The same summer he read Isaac Asimov’s The Ends of the Earth about the melting icecaps and warming seas, he was fishing off southeast Alaska. One day, the crew hauled up something in the net that scared him. “We had a school of mackerel and a couple of sunfish,” he recalls. “I’d never seen those species in our nets before. I started asking around to the guys that had been fishing the longest, and nobody had seen those species before.” To him, it felt as if he had stared into the face of global warming.

0215_OSUMkt_1581

John Miedema explains how his furnace works to organic farmers and others who are curious about the benefits of biochar. (Photo: Karl Maasdam)

Later on as he browsed the Internet, his mind awash with ideas about systems theory and his heart full of alarm over Earth’s peril, he Googled “carbon.” Up popped “biochar.” He had found his sustainability grail.

Starker Forests and Thompson Timber, where Miedema was by then the director of biomass energy, invested in his biochar venture, footing the bill for the furnace fabrication at a defunct mill in Philomath. It wasn’t long before he was charring 100 pounds of biomass an hour and reaching out to OSU scientists to test its structural and chemical properties.

Meanwhile, the community of char-minded folks around the region was growing faster than fireweed, everyone communicating through a burgeoning listserv. In 2009, biochar was a hot topic at a series of workshops on bio-based products held in Tillamook, Klamath Falls and Pendleton. Put on jointly by OSU’s Institute for Natural Resources and Oregon BEST (Built Environment & Sustainable Technologies Center) to catalyze new markets for Oregon’s sagging rural economies, the workshops brought together researchers, wood products companies, local governments, tribal representatives and others to brainstorm and strategize about new uses for woody biomass. “I came away with a concrete funding opportunity that could enable Douglas County to purchase a $350,000 piece of mobile equipment that converts biomass at logging sites into the right type of chips for biofuels and biochar,” reported Douglas County Commissioner Joseph Laurance. Other participants left the workshops eager to get more scientific findings on biochar, including data on carbon sequestration, soil amendments, pyrolysis technologies and the economics of transporting biomass versus processing it onsite.

Black Earth

“Designer biochar” might sound like the pinnacle of 21st-century eco-technology. But humans have known the potent properties of burnt wood for 2,000 years, since the indigenous people of the Amazon Basin discovered an incredible boost to fertility in soils enriched with char and other organic wastes. The Portuguese later called this engineered soil terra preta, “black earth.” In Japan and Korea, farmers have long enriched their soils with charcoal.

“I’ve Never Been So Excited”

Meghana Rao, a senior at Jesuit High School in Portland, studied biochar with Oregon State Professor Markus Kleber. Last spring, she discussed her findings with President Barack Obama.

Read more…

“Biochar is a new twist on an old concept,” notes David Smith. “It’s an opportunity for upgrading wood waste, for turning low-grade materials into high-value products that can boost rural economies. But before we can take it to market, there are a zillion performance questions to be answered – questions about feedstocks, particle size and so forth – along with standards and specifications to be developed.”

One question has to do with water flow. While scientists know that biochar captures pollutants along with storm water, they don’t yet know how well that water flows through those biochars.

“When storm water occurs, we get a whole lot of it all at once,” says OSU hydrologist Todd Jarvis. “If you can’t get the water through the medium efficiently, it’s not going to be worthwhile for storm water treatment.” So last year, he and chemical engineering professor Christine Kelly worked with student Perry Morrow to design hydraulic experiments based on Darcy’s Law, an equation for describing the flow of a fluid through a porous medium. “We were looking at the physical hydraulics – the flow rates – of biochar,” says Jarvis, who directs the Institute of Water and Watersheds at Oregon State. “How much water can go through it in gallons per minute, cubic feet per second? Is it laminar flow, or is it turbulent flow? Are flow rates a function of the size of the biochar? The shape? The compressibility?”

Orange-Hot

Miedema stands in the long shadow of his towering furnace when a van pulls up and several people pile out.  A couple more cars straggle in, a few more people join the group. “I love biochar!” one man, a farmer, says during introductions. “I’ve never heard of it,” a woman admits. They’ve come to Philomath from Oregon Tilth in Corvallis, Organic Materials Review Institute in Eugene and the Corvallis Parks Department “peer learning group” for sustainable landscaping to hear Miedema talk about biochar and assess its suitability for gardening and organic farming.

Squinting in the summer sun, they watch and listen as Miedema tells the story of biochar while showing off his furnace. “I can produce a wicked amount of heat,” he says, pointing out the throttles and valves that control temperature. “It gets orange-hot in there.” When he comes to the part about biochar’s longevity in soils – it takes 500 to 1,000 years before microbes break it down and release the stored carbon – he brings the talk around to climate change, to Asimov’s prescient book from 1975 that first alerted him to the looming threat. The carbon in biochar, he says, lasts for centuries sequestered in the soil. In this way, biomass becomes a means of taking CO2 out of the atmosphere instead of letting it become a greenhouse gas during rotting or burning.

“Biochar,” he says, “has very good uses for humans and the environment, for bettering our health and for cleaning up the legacy of toxins we’ve left behind. We have a lot of work to do to clean up that legacy.”

Leave a Reply


two × 4 =