Opinion

Pig poop paving one way to cut oil dependency

By Robin Baranyai, Special to Postmedia Network

(Postmedia Network file photo)

(Postmedia Network file photo)

Canada is a vast nation of disparate geographies: an immense network of rivers and lakes, frozen tundra, rugged Shield and rich farmland, reaching from coast to coast to coast. Before railways belted the continent, crossing the country was a three-month endeavour, as Sir Sanford Fleming undertook in 1872, by oxcart, horse and boat.

Transport today is a much quicker affair. We are a nation of drivers. Canada has the equivalent of one million kilometres of roads, concentrated in the provinces.

In 2003, the three territories had just one per cent of the country's road network between them, according to Statistics Canada, most of it unpaved. Vast areas of Canada's North remain inaccessible by car or truck. All our roads are in a constant state of degradation and renewal. As attested by our two fabled seasons -- winter and road repair -- asphalt pavement is not terribly resilient to changes in temperature. It's made with low-grade petroleum binders -- mixed with crushed stone, sand or gravel -- which crack with repeated freezing and thawing.

A team of researchers has developed a promising new asphalt with improved cold-weather performance. In fact, the technology achieves a coveted manufacturing trifecta: it diverts waste, lowers costs and reduces petroleum dependency. And it comes from an unexpected, highly renewable resource: pig poop.

Researchers at North Carolina Agricultural and Technical State University have developed a process to isolate petroleum-like oils found in swine manure. The resulting black crude is too low-grade for gasoline, but can be turned into "PiGrid," an effective bio-binder in asphalt. In interviews, lead researcher and civil engineer Ellie Fini says it's cheaper to produce than petroleum binders, and the final product outperforms regular asphalt. Her development team formed the company Bio Adhesives Alliance Inc. to file patents, and has won several industry prizes for clean energy innovation.

Pig manure is eminently renewable and abundant, thanks in part to the popularity of bacon. Pork production in Canada is a $3 billion industry, with 13.26 million hogs on farms across Canada, according to the Canadian Pork Council. In the five or six months it takes to reach market weight, each pig can put away roughly 360 to 450 kilograms of food. That's a lot of manure - an estimated 195 billion litres a year worldwide.

Some of it is used as fertilizer, rich in nitrogen, potash and phosphorus. But storage can be an issue. There are regulations governing how, where and when manure can be applied to land as fertilizer to avoid contaminating water sources. Farm waste management plans require the manure be held in storage lagoons until the appropriate time for spreading. These lagoons take up significant real estate.

It's a challenge for farmers as urban development puts increased pressure on land use, particularly in the researchers' home state of North Carolina, where the concentration of hog farms is much higher. And then there's the smell.

The new asphalt offers a promising alternative. Fortunately, the manufacturing process filters fatty acids from the manure, eliminating the characteristic odour.

It's one of several innovative approaches being pursued by green pioneers. Another is rubberized asphalt concrete, a paving material that mixes asphalt with ground-up rubber tires. And federally funded research in the U.S. is exploring the use of roads to create solar energy by developing durable photo voltaic panels the width of highway lanes.

We haven't shown much progress in kicking our addiction to cars; through green innovation, at least we can make our roadways more sustainable.

write.robin@baranyai.ca