CALGARY -- Calgarians are flushing money down the toilet -- or at least that's what the city is hoping, as it looks to squeeze a profit from your poop.

It's not a tale for the squeamish, but filthy lucre is the motivation behind the city's latest business venture, through which officials in Calgary's wastewater department plan to sell treated sewage.

Make that a mountain of sewage: "The City of Calgary is looking for interested parties to beneficially use up to 10,000 dry tones of dewatered biosolids ... and or up to 6,000 dry tones of thickened biosolids."

So reads the advertisement putting a feeler out in the local feces market, in hopes of finding someone who can use the rich fertilizer byproduct of Calgary's state-of-the-art water treatment plants.

Is there really market for human waste?

"That's what's under investigation -- we're finding out what the market will bear," said Dan Limacher. director of Water Services for the City of Calgary.

If Calgary finds a buyer, it'll be a major change for a program that's quietly provided free fertilizer to local farmers for the past 30 years.

Called Calgro, the city describes the concentrated mixture of toilet scraps as a "rich, organic fertilizer and soil conditioner suitable for use in agricultural production."

Every flush of the toilet adds to the sewage sent downstream to Calgary's sewage treatment plants, where solids are treated, then concentrated in storage ponds into what is called biosolid.

From there, the biosolid is loaded into tanker trucks and sent out to farms, where specialized crews inject the slurry of digested sewage into the ground, up to 10 cm deep.

It's not something most citizens think about, but Calgarians clearly spend a lot of time on the throne -- and that means a lot of biosolids to bury.
Each year, it takes 10,000 tanker truck loads to ship 20 million kilograms of waste out of the city, where it ends up enriching enough neighbouring farmland to cover Nose Hill Park twice over.

It's strong stuff too -- and not just from the smell.

Farmers using Calgro's finest can't use it more than once every three years on the same field, as the nitrogen levels typically soar after the fertilizer is applied.
And unlike traditional manures, extra precaution over potential disease mean the waste can't be used in certain crops, like root vegetables, or near human habitations.

Though there's no evidence of anyone ever getting sick as a result of biosolids, its restricted to crops that include forage, oilseed, small grains, commercial sod and trees.

On the other end of the equation, crystal clean water flows downstream of Calgary -- water that's won awards as the cleanest treated water in the world.
"The City of Calgary gets many accolades for its waste water treatment and the quality of water going downstream, but what everyone forgets is the solid we take out," Limacher said.

But it isn't free to make human fertilizer, or to ship and bury it around Calgary.

As of 2011, the estimated annual cost of the Calgro program was $3.50 per citizen, and with eligible land getting harder to find, the city is hoping to find a commercial buyer for the biosolid waste.

Whether it makes us stinky rich or not, city council's environmental watchdog says keeping Calgary's toilets from filling the landfills is a worthy endeavour.

"I think it's great," said Ald. Brian Pincott, an outspoken supporter of green causes.

"So little of it ends up being wasted when it comes to our wastewater system -- it really is second to none in the world."

Calgary isn't alone in using biosolid fertilizer, with similar programs in the U.S., Australia, Europe and China as well as Edmonton, Toronto, Ottawa, Saskatoon, Regina, Waterloo, Red Deer and Lethbridge.

And though the thought of human poop feeding plants might make some people queasy, Pincott says it's a natural process that helps the environment.

"At the end of the day, it's not all that gross," Pincott said.