A better biocell (1/26/2008)

Graduate studen Omar Hurtado (left) is working with Dr. Patrick Hettiaratchi (right), principle investigator of the Biocell Pilot Project at Calgary's Shepard landfill site. Hettiaratchi's Biocell Research is helping to find practical ways to decrease Calgary's environmental footprint.

As Calgary grows, so does its environmental footprint. At current rates, city landfills will be used up in 30 to 40 years. However, a new approach to waste disposal could extend the lifespan of Calgary landfills to a century. This University of Calgary-designed technology is already turning garbage into fuel.

A "biocell" encloses a would-be landfill, and with Mother Nature's help, breaks down biodegradable materials in the garbage. The full-scale Biocell pilot project at Calgary's Shepard landfill site has been in operation since April 2005. Covering almost a hectare, it has been fed 65,000 tonnes of residential garbage.

Biocell project leader Dr. Patrick Hettiaratchi works with the University of Calgary's Centre for Environmental Engineering Research and Education (CEERE). He says that the Biocell is a waste facility, not just a garbage dump.

Traditional "dry-tomb" landfills are not sustainable, explains Hettiaratchi. Once each unit, or "cell," at a site is full, it's full. The site can be covered and used for parkland, but the terrain isn't solid enough to support large buildings. "The biggest benefit of the Biocell is, if it works well, you can use the same space over and over again." In about eight years, the Biocell will be mined for metals, other non-biodegradable materials, a compost-like product and ready for re-use.

Biocell gas not just hot air

At first, bacteria in the Biocell's oxygen-free interior will chew up garbage and release methane. So far, the system is producing significantly more methane than a traditional landfill. Since November 2006, Biocell gas has been helping to fuel an onsite electricity generating plant. Later on, oxygen will be introduced into the Biocell to encourage the growth of composting bacteria.

Another unique feature of the system are the granular "biocaps" covering sections of the Biocell. Bacteria within the biocaps convert uncaptured methane into carbon dioxide, a less potent greenhouse gas. At the same time, the bacteria clean the gases of unhealthy volatile compounds.

Note: This story has been adapted from a news release issued by the University of Calgary

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