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OTTAWA – The City of Ottawa can reduce its sewage overflows into the Ottawa River by 60 per cent for $25 million, says the city’s top water official, but the cost of a total clean-up could be hundreds of millions.
The city routinely lets sewage overflow into the Ottawa River because of this summer’s almost constant rain. When the combined sanitary and stormwater sewer system that covers older downtown neighbourhoods nears capacity during rainfalls, regulators are opened to deliberately divert some of that stormwater and sewage into the river. While the mixture is heavily diluted, the overflows are in the thousands of cubic metres, which the city monitors and reports to the Ontario Ministry of the Environment.
Sometimes the regulators, which are more than 50 years old, malfunction and sewage unnecessarily spills into the river. The province has charged the city over a failure to report a huge spill in 2006. There have also been two more minor spills this summer. City staff are now physically checking the regulators after every rainfall to make sure they’ve closed properly.
Dixon Weir, Ottawa’s director of water and wastewater services, says that $25-million worth of equipment upgrades to the sewer system, called the Real Time Control program, are under way, mostly involving upgrades to the equipment at several regulators. With new computerized equipment, the city will be able to operate the Ottawa Interceptor Sewer – the last-ditch protection for the Ottawa river, taking sewage along the river to the Pickard sewage treatment plant at Green’s Creek in Gloucester – at a higher capacity. That should mean less overflow into the Ottawa.
In an average year, about 400,000 cubic metres of mixed sewage and rainwater flow into the river, according to the city’s mathematical models of the overflow (the system doesn’t actually measure the amount). With the upgrades, the city expects that to drop to about 165,000 cubic metres a year. The new equipment should also put an end to the unnecessary spills that result from the decrepit regulator gates. It will also mean the city will no longer have to make educated guesses about the amount of sewage flowing into the river.
The $25 million in work mostly involves the four major locations where the city releases water and waste into the river. Work on the biggest of the discharge sites, the Rideau Canal interceptor just north of Wellington Street, began in January, but had to be suspended for summer so as not to interfere with the tourist season. The city expects the work at that site to be finished by the third quarter of 2009. When it is, the number of overflows is supposed to fall from 38 a year at that site to 15.
The final piece of work in the project will be the equipment in the Booth and Preston Street areas, to be completed in 2010.
Mr. Weir noted that the city has come a long way since the 1960s, when all sewage was dumped directly into the Ottawa River, and that many Canadian cities are far behind Ottawa on sewage treatment. However, he acknowledges it is playing catch-up with machinery.
“We’re working with tired equipment that is prone to failure,” he says.
Once that equipment is replaced, the city will turn to other strategies for reducing the amount of untreated waste dumped into the river. City officials believe this could run into the hundreds of millions of dollars and may not be considered reasonable value for public money.
In the older west-end parts of the city, untreated stormwater flows directly into the Ottawa River, carrying with it animal waste and other nutrients bacteria love to feed on. That helps account for the high E. coli bacteria counts that regularly shut down Westboro Beach. The city could construct a stormwater-treatment facility there.
The city could also improve the quality of the water in the Ottawa River by further upgrading the treatment process at the sewage plant at Green’s Creek.
The city has more work to do separating sanitary and storm sewers in older neighbourhoods, such as Manor Park; fully separate sewers wouldn’t be subject to routine overflows at all.
City staff have told councillors they will report on what projects will help improve the Ottawa River’s water quality for consideration during upcoming budget deliberations.
(C) Ottawa Citizen