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Column: Not your garden variety bio-solids |
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Column by Carolyn Heiman, Times Colonist
Published: Wednesday, August 15, 2007
Sewage plants are making the news this year.
While the Capital Regional District is working on building its first plant, the Comox Strathcona Regional District is taking the matter very literally. It's growing plants in a soil amendment made from its sewage, or more specifically biosolids from its wastewater treatment.
They're not just any plants. They are very, very big plants, growing
from two to five times larger than others grown in topsoil and fish
compost mixes. "It certainly exceeded my expectations. The comparison
is quite astounding," says Jim Elliot, the region's wastewater manager.
Corn plants reach for the sky in a Comox Strathcona Regional District
test garden treated with a soil amendment made from human waste.View
Larger Image View Larger Image
Corn plants reach for the sky in a Comox Strathcona Regional District
test garden treated with a soil amendment made from human waste.
Even grass grows twice as fast using the soil amendment - a factor best
not used in the marketing material - that is sold in bulk under the
name of SkyRocket at the CSRD composting facility in Cumberland.
Likewise Humanure - briefly considered as a brand name - isn't likely
to add to the material's cachet for consumers. But under SkyRocket the
material, created by mixing liquid waste biosolids with wood chips and
then heating the heck out of them, is a hot seller as is a similar
product called Ogogrow in Kelowna.
All of which shows we've come a long way - or maybe full circle - from the outhouse.
This is the fourth year the CSRD has made the product, but just the
second year of selling SkyRocket to the public. Until now the region
used it in slope stabilization and land reclamation projects at its
landfill and a coal slag mine. Elliot expects the region will likely be
in a break-even position after selling 4,000 cubic yards of the
material this year and saving the cost of disposing of the biosolids.
Would Elliot use it on his vegetable gardens? It is, after all, made
from you know what. And wasn't it just last year we had the tainted
spinach scare?
Elliot says the CSRD heats the biosolids to 65 degrees Celsius to kill pathogens.
As for using it on his own garden, absolutely he would and does.
The CSRD is testing their vegetables to determine if there is any
uptake of minerals, metals or pesticide and comparing them with
vegetables purchased at a grocery store. Under provincial government
regulations, the CSRD has to test SkyRocket for pathogens, nutrient
value, moisture, pH and metals including arsenic, cadmium, chromium,
cobalt, copper, lead, mercury, molybdenum, nickel, selenium and zinc.
You find metals in most soils, says Elliot, adding that some of those
metals such as selenium and zinc are important in a person's diet.
SkyRocket is considerably below threshold limits for worrisome ones
such as lead and mercury.
But for some people, that's a problem.
Stephen Salter, who has been lobbying via the Victoria Sewage Alliance
for the Victoria region to convert its future biosolids into energy,
argues the day may come when limits set by regulators won't be
acceptable. While he applauds Comox for finding a positive use for its
biosolids, he hopes Victoria can do better.
Roger Colwill, International Composting Corp. vice-president, goes
further, saying many consumers don't think its a good idea to use
biosolids so his company doesn't accept them in its processes.
Dwayne Kalynchuk, the CRD's general manager of environmental services
and the man with the behemoth task of leading the Victoria sewage
project, says using biosolids to create compost will be examined,
although he sees a growing reluctance from people to use it.
"It is the perception that it comes from human waste," said Kalynchuk.
And, he adds, the CRD will also factor in the greenhouse gas emissions
making and transporting it produces.
Ultimately, he says, it's likely best not to put all your hopes on one approach.
Read a Response Letter from CACG
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