Wednesday, January 18, 2012

Flushing our sewage into waterways unacceptable

 By Jim Mosher

Wastewater treatment has advanced since the halcyon days of ancient Rome — with a noted exception. As did the Romans, we continue to dump sewage into our waterways.

We remove the obvious bad stuff but are forced, by technological limits and a lack of political will, to leave a whole bunch of bad stuff in the treated sewage we discharge into our waterways. If the Romans treated their sewage at all, it was by incidental dilution because its sewage system was combined with its drainage system.

The combined sewer system in Winnipeg isn’t much different; seems we haven’t advanced much since ancient Rome. During heavy rainfalls, snowmelts and watermain breaks, Winnipeg’s system simply overflows. That results in raw sewage entering the Red and Assiniboine rivers. It is well documented that such events cause nutrient loading of waterways and can lead to fish kills in the receiving waters.

This situation is no longer tolerable.

One cannot blame the members of Winnipeg’s current city council entirely. They were not around when the city’s combined sewer system was built decades ago. But they can be blamed for dragging their feet on construction of a new system. Yes, the price tag is in the hundred of millions of dollars — it’s a price we should all share. Let’s get on with it.

Though the sewage of the modern moment has been ‘treated’, it continues to foul our lakes and streams with a host of contaminants. It’s not as noxious as the pollution that flowed into the Tiber River from the sewage systems of long-ago Rome but it remains a toxic brew.

The effluent that comes out after sewage is treated contains nutrients that stress out waterways, as well we know; but that effluent also contains pathogens, toxic chemicals, household products, hormones, antibiotics, pharmaceuticals and road salt, according to the 15th Biennial Report of the International Joint Commission (IJC), released in January 2011.

“The sources of these threats include: failing septic systems, leaking underground storage tanks, hazardous waste sites, abandoned wells, leaking sanitary sewers, confined animal feeding operations, de-icing practices, landfills, land application of manure, agricultural practices, spills, atmospheric deposition, vehicle fluids, cemeteries, petroleum refineries and injection wells,” the IJC report states.

But that’s not all, there are ‘chemicals of emerging concern’, chemicals that are unregulated or inadequately regulated. “Wastewater treatment plants, one of the leading conveyors of these chemicals to the nearshore [of waterways], are not designed to remove them,” the report notes with some understatement.

Dumping ‘treated’ sewage into waterways then is a game of ecological Russian roulette. While there is no ready solution, there are alternatives available, including composting and combustion toilets — choices that are out of the financial reach of many. Constructed wetlands  absorb nutrients and take up microorganisms that otherwise foul our waterways; they have proved effective in some locales. These man-made wetlands offer an additional level of treatment, but they’re usually only suitable for smaller communities; city-scale use of constructed wetlands would consume too much land.

The chemicals we know are washed out with our effluent and the others of ‘emerging concern’ can probably be removed with additional, likely costly, layers of treatment. Those innovative design approaches may be decades away.

In the absence of a ready solution, municipalities will continue to treat their sewage to the standards now in place then allow that effluent to run into our waterways, whether from lagoons or wastewater treatment plants.

We have become too accustomed to ‘washing away’ our sewage with water, says David Schindler, Killam professor of ecology at the University of Alberta. Is there an alternative? Not in the short term, says Schindler.

“I really think, though, that in the long term we need to get away from the 19th-century notion that water is just there to wash away sewage,” Schindler said in an interview with the author in 2007. “Composting and combustion toilets — I think we really need to be turning to that on a large scale.”

Many jurisdictions offer modest incentives to switch to low-flush and alternative toilets. We could adopt a more aggressive approach. New-home builders and sellers should be required to install toilets that reduce or remove both water and organic material from the wastewater stream. This would not increase the price of a home by a lot, but it could make a difference over a few decades.

The incremental nature of fundamental change is frustrating because it will take years for our actions to have a measurable impact. Staying with the status quo will only exacerbate the problem. We must, at the least, take the baby steps that are required. And soon.

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