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UBC prof has suggestions on how to deal with future drought conditions

(iStock Photo)

VANCOUVER (NEWS1130) – Despite the fact our weather has taken a dramatic turn, Metro Vancouver is still under stage three water restrictions.

But have we learned any lessons or could we face a similar situation next year?

One expert at UBC has a suggestion about how to prepare for future droughts.

Engineering professor Troy Vassos says we could be making much better use of greywater.

So what is it?

“Greywater is the water that we associate with the drainage from bathtubs, showers, bathrooms sinks and laundry. It’s referred to as greywater because the soap and detergents in the water give it a grey colour,” explains Vassos.

Re-using the untreated water to flush toilets and water lawns already happens in Australia and parts of the southern US.

“(There) greywater is allowed to be used directly for sub-surface irrigation and shower landscape irrigation. In some circumstances it can be used directly to flush toilets by sending the greywater to the back of the toilet tank and flushing the toilet,” says Vassos.

And there are interior uses for it too, that can save a huge amount of water.

“Greywater from the bathtub is about 35 per cent of the amount of water that a house uses. And it turns out that flushing a toilet is about 30 per cent of the water that a house uses. Therefore in a residential setting, using that same water to flush a toilet would make a lot of sense and would save 30 per cent of the water,” he adds.

Water from toilets and urinals is referred to as blackwater and whether kitchen sink and dishwater drainage, which contains food waste, is grey or black depends on the jurisdiction.

Health Canada doesn’t differentiate between treating the two types in its national guidelines on reclaiming wastewater for non-potable home and commercial use.

Greywater can also be collected from apartment complexes, treated and re-used as drinking water, further conserving our supply.

“If one was going to collect water from an apartment building, it would make more sense to collect all the wastewater together and treat it to a safe standard that could be re-used in the building. There’s an example of this in North Vancouver in Quayside Village.”

Vassos says BC already has the most progressive legislation for water reclamation in Canada but that much more can be done.

Major urban cities like Tokyo and Beijing already decentralize wastewater treatment to individual buildings.