Our good friend algae is at it again and is cleaning smokestacks!
A mixture of hot gas rises out of a flue stack at the St. Marys Cement plant about 50 kilometres west of Waterloo. But not all the CO2-rich exhaust is vented to the open air.
Some is redirected through a 15-centimetre thick pipe connected to the side of the stack. The pipe carries the gas into a high-tech facility where a species of algae from the neighbouring Thames River uses photosynthesis to absorb the carbon dioxide and release oxygen in return.
“It’s a small model of what a big full-scale facility could be,” says Martin Vroegh, environment manager with St. Marys Cement Inc., headquartered in Toronto. The algae project, which went live last fall, is believed to be the first in the world to demonstrate the capture of CO2 from a cement plant.
The idea, Vroegh explained, is to turn CO2 into a commodity rather than treat it as a liability. The CO2-consuming algae will be continually harvested, dried using waste heat from the plant, and then burned as a fuel inside the plant’s cement kilns. Alternatively, the green goop can be processed into biofuels for the company’s truck fleet.