Next summer when children are kicking around the ball, picnicking with mom and dad, or just having fun in Sandy Hill Park, they will be doing so on top of a massive sewage storage tank.
When completed, city officials say there won’t be any evidence a 11,236-cubic- metre underground storage tank—with the capacity to hold 12.5 million litres of combined storm water and raw sewage—lies beneath the park.
Once the tank is built, the park, located behind the Sandy Hill Community Centre, will also get a major facelift.
SEWER BACKUP
The $15-million tank, the first of its kind in the city, is being constructed to alleviate the pressure on the Somerset trunk sewer. As Sandy Hill residents have experienced on many occasions over the years, when a major rainfall occurs, the sewer line backs up—usually into their basements.
During a major rainfall, sewer flows will be directed to the tank, which is divided into two cells. One is a smaller chamber designed to hold the overflow from a major storm, while the other is designed to handle a storm of the century.
Dixon Weir, the city’s director of water and wastewater services, said the tank has enough capacity to protect all homes and businesses in Sandy Hill.
The tank will also help minimize the combined sewer overflow into the Ottawa River, he said.
Some parts of Ottawa’s aging sewer system feature combined sewers. During heavy rainfall, both raw sewage and storm water flow through the same pipe and when levels are too high for the system to handle, the mixture enters a bypass that overflows into the river.
“There is enough storage capacity to prevent basements from flooding,” said Weir. “This will contribute to improving the overall collection of combined sewage. This is the perfect solution for this problem.”
After a storm, once the main sewer line can handle the contents stored in the tank, the sewage will be released gradually and flow to a wastewater treatment facility.
ACTS LIKE BOWL
Darryl Shurb, a senior project manager with the city, said the topography of Sandy Hill is such it acts like a bowl and sits at the same level as the Ottawa River. During a heavy rainfall, the water flows into the neighbourhood and causes surface flooding.
As part of the project, several roads in the area have been excavated and 100-year-old sewer pipes replaced. A control facility will be housed in a building on site. The building will also include separate change rooms for the wading pool and hockey rinks expected to be built in the park. Staff at the water treatment plant will monitor the control facility.
“By the time the park is completed, it will be 100% better than it was before,” said Shurb.
The project is ahead of schedule and expected to be under budget, he said.
A large vacuum system has been installed in the control building to deal with odours from the sewage.
(C) Ottawa Sun