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The amount of combined untreated sewage and rainwater flowing into the Ottawa River has been reduced by more than a half since 2006, city officials announced Friday morning.
After years of struggling to control the amount of raw sewage entering the river, and millions of dollars in investments, officials were pleased to report a positive development.
“Our residents told us loud and clear during public consultations they want the nation’s capital to be a world leader in the control of combined sewer overflows,” said Councillor Maria McRae, who chairs council’s environment committee.
“The public wants a clean river and this is they way to reach our goal of reducing these runoffs to zero in an average year.”
The city’s not there yet, but it has made major improvements in the last five years. In 2010, 424 million litres of combined sewage and rainwater overflowed into river, compared to almost 1.1 billion litres in 2006.
So far, an estimated 283 million litres of combined sewage and rainwater has spilled into the river this year, according the city website, where the city voluntarily posts overflow figures.
The improvement comes from $100 million invested through the Ottawa River Action Plan. Of major importance to the reduction in overflows is the “real-time control” technology the city implemented at five of the city’s water regulators. The new electro-mechanical systems allow more of the waste water to remain in the system, so less overflow is released.
The next major step in reducing the sewage spilling into the river is the construction of huge underground tanks that will hold the overflow during heavy rainfalls.
But construction of the project, which will cost a minimum of $140 million, will not start until the funding from other levels of governments have been officially committed, according to Mayor Jim Watson, who has been in discussions with his federal and provincial counterparts.
The primary obstacle to keeping pollutants from pouring into the river is the 120 kilometres of combined storm-and-waste water sewers in the older parts of the city. The combination sewers were designed to intentionally spill excess waste water into the river when capacity was exceeded, in order to prevent flooding and basement backups.
After extensive public consultation, the city has come up with a plan to store overflow in massive underground tanks, which are really a series of three-metre-wide tunnels totalling six kilometres in length and running from LeBreton Flats to New Edinburgh. The overflow can then be funnelled to the waste water treatment plant later on, once there’s enough capacity to handle it.
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