Accessibility and Access Keys [0]
The first phase of the city’s effort to stop dumping sewage into the Ottawa River during heavy rainstorms officially ended on Friday with the commissioning of a set of real-time controls over the flow in Ottawa’s downtown sewers.
Mayor Jim Watson, MPP Phil McNeely and MP John Baird, among others, gathered in a tent above a sewer near Booth and Albert streets for the event.
The more sophisticated sewage gates the city has installed in multiple sewer regulators under downtown replace antiquated ones that operated on the same general principles as household toilets: High levels of sewage, such as when rain or lots of snowmelt combined with the regular contents of sewers, would cause the old gates to rise and vent the excess into the river.
One such gate got jammed open during a storm in 2006 and allowed nearly a billion litres of raw sewage into the river over the following days, fouling the beach at Petrie Island downstream.
Sewers that ordinarily carry household and other human-made waste to a treatment plant in Gloucester weren’t working, but the city’s wastewater department had no way of knowing that it had happened.
The new gates come with monitors and active controls, so city workers will be better able to keep tabs on what’s happening underground and route flow in ways that limit the amount of sewage vented during storms.
The city is planning to build huge underground tanks to contain excess sewage till a storm ends, too.
The so-called combined sewers are only a problem downtown. Newer parts of the city have separate storm and sanitary sewers so that rain and snowmelt don’t risk overflowing the sanitary sewers.
The $250-million solution the city is in the middle of is meant to eliminate almost all the overflows, though not during the very heaviest rains.
However, tearing up and rebuilding all the roads to get at the downtown sewers to separate them and solve the problem entirely would cost billions.
© Copyright The Ottawa Citizen
Read more: http://www.ottawacitizen.com/Real+time+controls+place+downtown+sewer+flows/3926986/story.html#ixzz17du1HFYm