City officials have launched an aggressive plan to control the discoloured water problem by reducing levels of manganese in the water supply.
A consultant’s report identified a recent buildup of manganese as the cause of the brown water.
The plan includes cleaning the city’s reservoir and water lines and reducing the amount of manganese that enters the water supply.
"We’ve identified an issue and a path to the solution," Coun. Justin Swandel, chairman of the city’s public works committee, said during a morning news conference.
Members of council were briefed on the consultant’s report and city’s response to the problem at a morning news conference.
News media were briefed afterwards.
Diane Sacher, director of water and waste, said the discoloured water only recently became a problem for Winnipeg when the city’s new water treatment plant became operational.
Sacher said ferric chloride is used in the treatment plant as a coagulant – which binds small solids such as algae together in larger clumps, making them easier to remove.
However, the ferric chloride was also releasing manganese, a natural substance found in water and many liquids.
The treatment plan filters out ferric chloride but not manganese.
Sacher said the city is switching to an alternative ferric chloride with a lower concentration of manganese and speeding up its clean-up of water lines and the reservoir.
Reservoir cleaning is underway and water main cleaning will begin in May.
"While we expect it will take approximately two years to implement all the recommendations in the report, our customers should see a gradual reduction in discoloured water as each recommendation is implemented," Sacher said.
Sacher said discoloured water is a common occurrence at all water utilities across North America.
A consultant was first hired by the city in 2010 when reports of brown water escalated that summer. Samples found high levels of iron, which prompted that consultant to recommend a treatment solution which did result in fewer incidents in 2011.
But the numbers jumped again in the summer of 2012, which prompted the city to hire another consultant who later discovered the high levels of manganese, which were not present in the water supply in 2010.
The number of incidents reached seemingly epidemic levels in the summer of 2013.
Sacher defended the work of the first consultant, adding the findings and solutions were backed by research.
Coun. Dan Vandal, who persuaded council in the fall to accept claims for laundry damaged by discoloured water, said this latest report is the best information the city has to deal with the problem.
Time will tell if this is the best advice, Vandal said.
"The evidence will be less discoloured water in city taps … which I expect by next summer."
There were more than 1,600 incidents in August. The city’s goal is to reduce the outbreaks of discoloured water to traditional levels of fewer than 100 incidents per month.
One of the issues that perplexed many homeowners last summer was the presence of brown water at one home but not the neighbour’s
Sacher said the consultant explained that phenomenon occurring as a result of an affected household using a large amount of water while the other household did not, which resulted in large amounts of manganese entering a home’s water line and not their neighbours.
"The manganese is causing a coating on the wall of water mains," Sacher said. "That is disrupted when the flow velocity increases or the direction changes.
"This goes as a slug through the main. If you have your dishwasher going, a shower running, you would be bringing it in whereas your neighbour, if he wasn’t using water at the time, wouldn’t necessarily bring it in to his system."
While manganese levels are high, Mayor Sam Katz said health officials assured him they do not pose a health hazard.
"Our water is safe. Period," Katz said.
Sacher said manganese is found in many liquids, adding levels in tea and apple juice are much higher than those found in samples taken across the city.
Sacher said the city will hire a third consultant, at a cost of $500,000, to verify the findings of the second consultant and to monitor the city’s clean-up efforts.