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The answer to Ottawa’s water-pollution problem is not a $2-billion separation of storm and sanitary sewer systems but a decentralized system of wastewater storage tanks, according to the city’s engineers.
The City of Ottawa has been trying to figure out how to reduce its pollution of the Ottawa River for many years but recent embarrassing overflows and spills into the river have added urgency to that quest. The spills occur from the system during heavy rainstorms when the sanitary sewer system reaches capacity and sewage has to be diverted directly into the river.
For years, separation of the sanitary and stormwater sewer systems in established areas of the city was considered a long-term answer. But a report going to city council’s planning and environment next week says such a project would be horrendously expensive, at $2 billion or more, and would be extremely disruptive, taking 50 years and requiring new connections of sewers to 80,000 residences and commercial buildings.
And the project would not be a big improvement for the river because a lot of the stormwater — the water that flows along streets, parks and sidewalks — would end up in the Ottawa untreated. There’s little space in older neighbourhoods to build stormwater-treatment ponds.
Another alternative proposed in recent years has been a central storage tunnel under Somerset Street, a facility that would hold wastewater until the Pickard sewage-treatment plant has lower flows after a rainfall. But that is a huge engineering project that would cost hundreds of millions of dollars to design and build.
Now the city’s engineers, led by Dixon Weir, general manager of environmental services, say that a third alternative is best. Their report says a series of storage tanks could be built underground in neighbourhoods throughout the city, in which wastewater would be collected, then flowed to the Pickard plant when flow levels have dropped. The “distributed storage” system would cost only $45 million and be constructed over the three years.
Councillor Peter Hume, chairman of the planning and environment committee, said he is pleased the city’s wastewater engineering staff and their consultants were able to look at a big problem and come up with a new solution that would save taxpayers a lot of money.
Hume said that the storage system, together with some separation of storm sewers in certain neighbourhoods, and improvement of stormwater-handling capacity, would raise the city’s Ottawa River Fund from $139 million to about $203 million. The city would almost certainly ask the federal and provincial governments to help with the cost and Transport and Infrastructure Minister John Baird on Friday suggested he is keen to continue helping Ottawa reduce river pollution.
The city is this month starting another project to improve the pollution by building a new sewer regulator at LeBreton Flats.
City officials have been pointing out that Ottawa is just one of many cities in the country that diverts untreated sewage into a major waterway when there are heavy rainfalls. But elected officials such as Baird and Hume say it’s an issue that strongly resonates with voters, who believe it’s archaic to allow such practices. The city was fined $562,500 last year for a 2006 one-billion-litre spill of sewage that was not reported to the province.
“It’s bad news that we discharge to the Ottawa River at all. It’s good news that we’ve been able to put our minds to how to eliminate that and we’ve been able to come up with a solution,” said Hume. “We will be a leader in not discharging after we implement this. It will be the exception rather than the rule. We will be far ahead of other municipalities.”
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