February 1, 2005

Calgarians will reap the benefits of innovative landfill research

Garbage and where to put all is a real issue facing Canadian cities and major cities worldwide. University of Calgary Environmental Engineer, Dr. Patrick Hettiaratchi, has put a new spin on some existing ideas regarding sanitary landfills accepting biodegradable organic waste with his research into Biocell Technology. The researcher has entered into a pilot project with the City of Calgary and local industry associates which will greatly extend the lifespan of city landfills and also provide a relatively cheap source of energy, alleviating Calgarians of the burden of locating new landfill space while, at the same time, providing some economic benefit.

“Landfill space is not currently an issue in Calgary”, says Hettiaratchi, “but this research will save future generations a lot of grief, and money, and greatly reduces our impact on the environment.”

Current city landfills have a life of roughly 30-40 years. The implementation of Biocell Technology to Calgary Landfills stands to increase this lifespan to more than 100 years and also incorporates enhanced methane production/extraction as part of the process. The Biocell Technology has the potential to produce large amounts (300kW) of electrical energy. The incorporation of more Biocell’s could result in a significant alternative energy source for Calgarians, however Dr. Hettiaratchi is downplaying the economic benefit of the Biocell.

“Since oxygen will need to be piped into the Biocell during the aerobic mode of operation, which will require some energy, the extracted methane can be used in the operation of the Biocell as well. It is significant that the Biocell is self-sufficient, but certainly excess gas reserves could provide an economic benefit. ”

Hettiaratchi’s Biocell Technology research combines some currently established practices of using landfills for both composting and gas production. Individually, these concepts are not new, but the combination of these approaches is what makes this research unique.

The Biocell is an enclosed landfill and the concept is based on a multi year cycle. The Biocell will be operated first in the anaerobic mode for several years with a high rate of methane production. Gas production and extraction is the objective during the anaerobic mode.

Within the Biocell, as the waste decomposes, the resultant ‘leachate’ (liquid) is collected from the bottom of the cell and recycled back into the top of the cell. Creating greater moisture within the Biocell increases biological activity and thus greater amounts of methane are produced (slow methane production is an issue for current landfills). After 3-4 years, methane production decreases to a point where gas extraction from the cell is no longer cost efficient and the cycle switches to an aerobic phase.

Composting is the objective in later years of the cycle, which is accomplished by introducing oxygen into the cell. In the final year of the cycle, the Biocell is mined for recovery of recyclables and compost and is ready to begin the cycle again.

When Biocell Technology is fully implemented, several biocells will be operated concurrently: some in anaerobic mode and others in aerobic mode.

The Calgary Biocell pilot project is currently underway, with the pilot Biocell under construction and slated for commencement of operation later this year. The City of Calgary’s Waste and Recycling Services division is constructing the pilot Biocell with design assistance from a local consulting company and construction assistance from local contractors. The University of Calgary is responsible for Biocell performance monitoring as well as associated academic research. NSERC is providing research funding under a Strategic Grant to Dr. Hettiaratchi and his team of researchers.

Dr. Hettiaratchi’s research is conducted through the Faculty of Engineering’s Centre for Environmental Engineering Research and Education (CEERE).

For more information regarding the Calgary Biocell pilot project please contact:

Dr. Patrick Hettiaratchi
University of Calgary
Department of Civil Engineering
Telephone: (403) 220-5503
E-mail: jhettiar@ucalgary.ca

For more information regarding CEERE research initiatives please contact:

Dr. Anil Mehrotra
CEERE Director
University of Calgary
Faculty of Engineering
Telephone: (403) 220-7406
E-mail: mehrotra@ucalgary.ca

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Kirk Thurbide
Manager of Communications
Faculty of Engineering
University of Calgary
Phone: 403-220-2626
Email: kathurbi@ucalgary.ca