Concordia Journal Home > Archives > October 25, 2007 issue >

Using less to gain more 

By Karen Herland

Every day, most of us obliviously send a precious resource down the drain.

The Environment Canada website’s 1999 figures state that North Americans whose water use is not metered use 457 litres of water each day. Europeans use 200 litres of water per person per day. In sub-Saharan Africa, that figure is below 20 litres.

According to Heather Wray, researcher with Ensemble Terre-Ciel, up to 70 per cent of domestic waste water is “greywater.” That term refers to wastewater from all sources except the toilet.

Normally, domestic greywater from showers, laundry facilities and bathroom sinks, along with the more obviously contaminated water from the toilet, or the kitchen sink (which also carries animal fats, oils and grease), all goes, undifferentiated, back into the sewage system.

But increasingly, environmentalists are experimenting with ways to recuperate, filter and reuse greywater for flushing toilets or for irrigation projects. This effort cuts down on overall water usage, and, in some cases also allows for the retrieval of heat from the water.

Ensemble Terre-Ciel has been renting one of the greenhouse units on the 13th floor of the Hall Building for Wray’s greywater experiments for a model home project the company intends to have operating by next spring.

“The goal of Maison Productive House is to produce more than is consumed,” Wray said. Saving energy and resources and channeling them into productive uses is key to the project.

Ensemble Terre-Ciel got involved with Sustainable Concordia serendipitously last year because one of their staff members could see the greenhouse from their office, which was then on Côte des Neiges Blvd. Finding out how to access the facilities led them to Sustainable Concordia’s plans to reopen the site and they were able to get involved.

The greywater experiments were run by Wray with the help of student interns. Some earned independent study credit, and some were there as volunteers.
The initial water filtration experiments proved inefficient for the scale of the eight-unit housing project being constructed in Point St. Charles by Ensemble Terre-Ciel. A more elaborate three-stage biofiltration system is being installed to redirect greywater for subsurface land irrigation and toilets.

However, since producing year-round vegetables in a relatively small space is another goal of Maison Productive House, the greenhouse facilities have been repurposed.

Currently, experiments are underway to explore vertical gardens, as well as cold frames, which are “mini-greenhouses within a greenhouse” and can greatly extend the growing season for a variety of foods.

The space is also being used to determine the effectiveness of filtered greywater for irrigation projects.