Technology & Science

Your bath water could help save the Earth

Concerned about reducing their environmental footprint, some Canadians have started installing grey water recycling technology in their homes.
LEcohabitation, the Montreal home of environmental consultant Emmanuel Cosgrove, is the only Leadership in Energy and Environmental Design (LEED) platinum-level certified home in Quebec. (Giancarlo La Giorgia)
Canada boasts the third-greatest supply of renewable fresh water on earth, but only half of one per cent of the world's population. The notion that such a small number of people could ever exhaust this vast liquid wealth seems impossible — which may account for Canadians' distinction as the second most wasteful water users on the planet.

Despite the nation's faith in bottomless water reservoirs, between 1999 and 2004, almost a third of Canada's communities reported supply problems. Municipal governments, which manage water distribution to the public, are beginning to take greater conservation measures. In Calgary, for example, the South Saskatchewan River basin was closed to new water permits in August 2006 and water prices in the region are rising.

"This year may mark the first time Calgarians will pay more for water than electricity," says environmental consultant Emmanuel Cosgrove. "It's an unthinkable prospect, considering residential water is practically free in most of Canada."

Cosgrove is among those who support conservation through better use of recycled household "grey water." And he's showing how it can be done in his own home.

Going green with grey water

Cosgrove's home, also known as L'Ecohabitation, is a three-level row house that looks much like any other in Montreal's trendy Plateau Mont-Royal district - except that it happens to be one of the most eco-friendly dwellings in North America. It's the only Leadership in Energy and Environmental Design (LEED) platinum-level certified home in Quebec.

Concerned about reducing his environmental footprint, Cosgrove has outfitted the two-family dwelling with numerous water-conserving features, including rain catchers to irrigate a rooftop garden and dual-flush toilets. Still, Montreal's rainfall often isn't sufficient to keep the garden watered throughout the growing season, and he considers "using fresh, potable drinking water to flush toilets - typically 30 per cent of all household consumption - as completely nonsensical."

Grey water explained

Grey water, or sullage, is the term given to the cloudy waste water produced by bathing and laundering, as long as it contains no more than negligible amounts of contaminants, such as fecal matter, food particles or toxic chemicals.

Grey water is much cleaner, or at least more diluted, than black water (sewage) from toilet flushing, dishwashing or industrial uses. As a result, treating grey water so that it can be safely reused is a much easier and less complex process than dealing with raw sewage.

Recalling an article he had read on a website about recycling bath, bathroom sink and laundry waste water, or grey water, Cosgrove custom-built and installed a grey water recycling system in late 2006.

"The system collects and filters the house's grey water - about 80,000 litres a year - which supplies flushing water to two toilets and, during the growing season, supplementary irrigation for a green roof," he says. All told, half of the building's municipal water is recycled, and in summer the sewage output - essentially just the toilets and kitchen sink - is reduced by 90 per cent.

Additionally, being built almost entirely with recycled parts, it cost only a fraction of a comparable commercial unit - about $300, plus labour. "And since it uses a slow sand filter, there's no need to add chlorine, a known carcinogen," Cosgrove says.

The system upkeep costs are low, with the only maintenance requirements being bi-weekly clearing of a solids trap and annual replacement of filtration material. Apart from a pump that distributes the grey water for reuse, the system uses no electricity.

The recycling system also recovers about a third of the grey water's heat energy, providing financial savings that Cosgrove estimates will pay for the system in about 20 years.

"Instead of cold city water going straight to the hot water tank, it passes through a 100-foot [30-metre] copper coil in the initial grey water chamber, capturing some of its residual heat and reducing the hot water tank's electricity needs," he says.

Health precautions

Recycling grey water is a common practice in the Third World, usually for garden irrigation and often without any pre-treatment. It is simply poured onto soil, which, along with plant roots, provides natural filtration.

However, this type of dispersal can aerate potentially harmful bacteria that may be inhaled or contaminate food crops (sub-soil irrigation effectively removes this risk for fruits and vegetables grown above-ground). In perennially dry parts of the developed world, there is growing interest in safe forms of recycling grey water that eliminate dangerous pathogens.

Dennis Yasar founded Montreal-based Brac Systems in 2005, the only mass producer of greywater recycling systems in North America. (Giancarlo La Giorgia)
Montreal-based Brac Systems, founded by Dennis Yasar in 2005, is a pioneer in the field and currently the only mass producer of grey water recycling systems in North America. The company has outfitted four correctional facilities in the U.S., with over 70 commercial-scale systems, along with worker camps in the United Arab Emirates (UAE) and a vacation resort in Costa Rica, while more than  1,000 residential units have been sold to homeowners from the Southwest U.S. to Australia.

"In the UAE, water costs are extremely high. After just two months of use, the savings from using one of our systems pay for itself," says Yasar, though he notes that the norm for recouping costs is four to six years.

Yasar says the demand for his line of commercial and residential units has grown exponentially, due in part to increasing understanding of grey water and the value of recycling it.

Brac Systems' units divert bath, shower and bathroom sink water to a 100-micron filter that removes most soap, hair and other residues. A programmable chlorinator disinfects incoming water seven times a day, preventing harmful bacteria growth and leaving it near-potable, allowing it to be stored for weeks. The system's water is propelled by a pump, but in the event of a power outage, any grey water held in the reservoir is flushed away, replaced by municipal fresh water until power is restored; likewise, any greywater overflow is diverted to the sewer.

The systems range in price from $1,890 for the basic residential model up to $28,949 for a commercial model, and require regular cleaning and maintenance, including the replacement of chlorine tablets. But Yassar says persuading potential customers to invest their money and time to reduce their water consumption aren't his company's biggest obstacles.

"Our biggest challenge is lack of knowledge, even among plumbers, about what exactly grey water is and how it can be safely used," he says, noting that grey water recycling is currently only allowed in Quebec, Ontario, Nova Scotia, parts of B.C. and all aboriginal lands.

Joanne McCran, the green building project manager at the Light House Sustainable Building Centre, in Vancouver, is working at getting policymakers in her area to add a provision for grey water recycling into the building code.

Policy hurdles

"At the moment, grey water recycling technically falls under B.C.'s Health Protection Act, but there aren't any actual standards or guidelines," she says. McCran notes that, as in all other Canadian jurisdictions, approval for a grey water recycling system in B.C. is done on a case-by-case basis.

According to Ian Theaker, LEED technical manager at the Canada Green Building Council, even in the jurisdictions where grey water recycling is allowed, only a handful of grey water systems have actually been sanctioned.

"Since health and building authorities are typically unfamiliar with onsite grey water systems, and provincial plumbing codes don't yet recognize them, projects to date that have sought official approval have had to overcome significant regulatory barriers that have added cost and complexity," he says.

Coincidentally, Theaker lives at Quayside Village, a co-housing community in North Vancouver that has the only multi-housing unit grey water recycling system in the nation. Although, as a prototype, the system has had operations and maintenance issues, he is glad to be part of the test process.

"From my personal perspective, of course it feels good to know our water footprint is smaller," Theaker says. "I look forward to the day when everyone will be able to shrink it to a fair share of the resources and capacity of local ecosystem."