We’re flushing money and resources down the drain

To Dr. Nicholas Ashbolt, wastewater has great value, but realizing that value requires an infrastructure overhaul

Dr. NIcholas Ashbolt, right, believes that wastewater has value and we should stop flushing money and resources down the drain

Once you learn what Dr. Nicholas Ashbolt does for a living, you’ll never look at plumbing the same way again.

Ashbolt believes it’s time for a paradigm shift in the way we think about water, sewage and public health. From his perspective, wastewater has value and we should stop flushing money and resources down the drain. And he questions the wisdom of providing treated potable water for everything, including fighting fires.

Ashbolt is a world-renowned environmental microbiologist. Before coming to Alberta in late 2013, he worked as an academic and research scientist in Australia and Sweden, followed by seven years with the American Environmental Protection Agency. Today, he’s a professor in the School of Public Health at the University of Alberta, where he holds the Alberta Innovates Translational Health Chair in Waterborne Disease. His multidisciplinary perspective intertwines new approaches to public health, water conservation and resource recovery.

Take the urine diversion toilet, for example. “Eighty per cent of the nitrogen that we consume in our diet ends up in the urine stream,” says Ashbolt. “Why dilute that one per cent of the urine stream with 99 per cent of what else is in the sewer? It’s not a very sensible approach.”

And what does a urine diversion toilet look like?

As Ashbolt explains, “If you look into the little bowl of a urine diversion toilet, it looks like a conventional pedestal, except at the front there’s a little bit of a weir and a second hole if you like so that the urine can go down a separate bit of plumbing to a storage tank where it can either go in a vacuum or pressure sewer, pumped out to a central location where it can then be taken out to agriculture and injected into the ground as a high-grade fertilizer.”

The new concept here is to separate toilet water, what Ashbolt calls blackwater, from greywater, the water we flush down the sewer after bathing, washing clothes and so on. New systems can recover and recycle this spent water.

Waterborne pathogens constitute another aspect of Ashbolt’s investigations. His research suggests our current plumbing supports the growth of some pathogens that cause respiratory disease. Also, fecal germs can be propelled into the air like a giant sneeze whenever the toilet is flushed. People breathe in or pick up these germs by touching surfaces and then spread them around. Switching from our gravity system to vacuum toilets like those in planes, trains and boats could eliminate that problem.

“With a vacuum flush toilet, only half a litre or so of water, along with 60 litres of air, is needed to move that residual down the sewer,” Ashbolt explains. “That’s a much, much safer scenario because there are no leaks to the environment.”

A vacuum flush sewer system also facilitates the separation of greywater from blackwater and allows for the recovery of imbedded energy in residual waste. “If we connect kitchens to the blackwater system, for example, it’s a far more efficient way of recovering the imbedded energy in food and fecal residual, which can supply more than the total amount of energy used to treat all drinking and waste water services in a community,” says Ashbolt.

Using heat pumps, we can recover thermal energy from the greywater, says Ashbolt. We can also reclaim methane from the organics, as well as precipitate ammonium and phosphorus that can be returned to the earth as fertilizer.

According to the professor, countries like Germany, Sweden and the Netherlands are experimenting with vacuum flush blackwater community systems.

Thanks to funding from the Canada Foundation for Innovation, Ashbolt has constructed a premise plumbing lab at the University of Alberta. Instead of using more chlorine to treat water, he suggests it may be possible to harness the microbiomes in pipes to fight pathogens. “In the future, we may have an upstream plastic pipe filter – we call it a selector – that selects for the right probiotic microorganisms, to see whether we can deliberately colonize building pipes with preferential organisms that will suppress the growth of these opportunistic pathogens.”

The idea is not unlike eating yogurt with probiotics to restore balance to your intestinal tract, thus preventing ill health.

There remains, however, a significant challenge to adopting these new technologies: municipal bylaws stifle innovation.

But Ashbolt is already working with provincial authorities to reform the regulatory framework for water services and assess with local councils its implementation.

Veteran broadcast and online journalist Cheryl Croucher produces InnovationAnthology.com which can be heard online and on CKUA Radio. This is the fourth in a 10-part series sponsored by Alberta Innovates.


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The views, opinions and positions expressed by columnists and contributors are the author’s alone. They do not inherently or expressly reflect the views, opinions and/or positions of our publication.

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