The Village of Dunnottar started testing a system that filters phosphorus and nitrogen out of municipal waste water in 2008. Outflows of the phosphorus were reduced by 62 per cent, and similarly for nitrogen over the past two years.
If the community gets the green light from the province to fully implement this system, officials also hope to begin recapturing these nutrients, said CAO Janice Thevenot.
They’re doing this to help save Lake Winnipeg. It will also save the municipality money – a waste water treatment plant would cost millions.
Municipalities were already intrigued by Dunnottar’s experiment. More are bound to be.
“It’s not going to work in the city of Winnipeg,” said Thevenot. “But for the smaller communities, it becomes an affordable option. And it can significantly impact not just Lake Winnipeg, but all of our waterways.”
Last week the province rolled out new proposed standards for nutrient reduction in municipal and industrial waste water as part of its ongoing efforts to protect water quality in both Lake Winnipeg and other provincial waterways.
The new Water Quality Standards, Objectives and Guidelines were released in tandem with a State of the Lake Winnipeg report, developed by Manitoba Water Stewardship and Environment Canada.
The latter lays out the current and ongoing research into Lake Winnipeg’s water quality and water levels, algae growth and climate conditions and is the first comprehensive assessment of Lake Winnipeg since lake monitoring began in the late 1990s.
The former calls for municipalities to adopt water quality standards and reduce phosphorus discharge in waste water discharges by 2016.
Association of Manitoba Municipalities (AMM) president Doug Dobrowolski said the proposed regulation was expected.
“It’s a regulation that’s consistent with the Lake Winnipeg Stewardship report,” he said.
COST OF COMPLIANCE
The new standards won’t require physical upgrades. Rather, the cost of compliance will come through annual purchase of new and different chemical treatments from those municipalities are already using to reduce nutrient load in waste water, Dobrowolski said.
Those costs are estimated at anywhere from $20,000 a year for a smaller lagoon system to upwards of $120,000 a year for larger facilities, Dobrowolski said.
Some municipalities may view this as “another download” from the province, he said. “But it’s just something we’re going to have to deal with. We were part of the Lake Winnipeg Stewardship report. We want to ensure that the proper things are being done.”
Thevenot says the system Dunnottar is trying would result in none of those kinds of ongoing costs while achieving the same desired result. This also allows for ongoing measurement of nutrient outflow.
“We’ve done extensive testing on our lagoon on what’s in it and what’s being released. We know. But most places don’t.”
The proposed provincial regulation calls for concentrations of phosphorus in waste water effluent discharged must not exceed 1.0 mg/l total phosphorus.
The State of Lake Winnipeg report is meant to serve as a reference for measur ing progress towards reducing nutrient loading.
Lake Winnipeg is generally classified as eutrophic or hyper-eutrophic, meaning the lake is highly enriched with plant nutrients. The new report says from 1999 to 2007 the average total phosphorus concentration in the lake was almost three times higher in the south basin and narrows (at 0.113 mg/l ) compared to the north basin at (0.044 mg/l).
On average, the report says, about 60 per cent of the phosphorus and 54 per cent of the nitrogen transported to Lake Winnipeg by tributaries and atmospheric deposition was retained in the lake.
Rates of nitrogen and phosphorus export per hectare were highest in the Red River and its tributaries compared to other major tributaries to Lake Winnipeg.
Suspended solids, such as mineral and organic materials derived from within the lake and through tributaries from erosion, may also carry absorbed nutrients, the report says.
A paleolimnological study, or study of core samples of lake bottom sediments deposited over the centuries is underway and expected to provide more data on changes to lake water quality since the early 1800s.
The province will meet with municipalities and stakeholders this month to discuss the updated nutrient removal standards. A public comment period lasts until August 4.
The documentWater Quality Standards, Objectives and Guidelinesand the Clean Water Technology Strategy is found at www.manitoba.ca/waterstewardship.
– DOUG DOBROWOLSKI, AMM PRESIDENT