It was a crappy situation at the Old Trail Bridge Monday.
The regional district’s main sewage line came apart above the Columbia River underneath the bridge’s deck in late afternoon, spilling around 5,500 cubic metres of largely liquid sewage into the river over the next few hours.
The regional interceptor pipe that services Rossland, Warfield, Rivervale, Oasis and West Trail was comprised of several sections of steel pipe, held together with a clamp, securing it to the piers of the bridge high above the river, said Alan Stanley, director of environmental services with the Regional District of Kootenay Boundary.
But the clamp’s failure was a mysterious occurrence, said Stanley, considering there was no normal operation of a pressure main that would result in the separation of a coupling.
“We are investigating that for some alternative reasons as to why it happened,” he said Tuesday. “At this point there are a bunch of ideas floating around, but until we have something more definitive we are a little reluctant to say exactly what it is.”
The RDKB had an emergency response plan for such an event and it was activated soon after the line came apart, pulling in regional district, City of Trail, Ministry of Environment and Environment Canada officials by 5:30 p.m.
Regional district liquid waste management crews had the sewage spill contained within a few hours after the leak was spotted.
Although the sewage pumps could not be turned off, the crews were able to send the liquid sewage through a bypass valve into the river, while solid waste went into a holding tank.
As a result, the RDKB immediately informed the Provincial Emergency Program as to what was happening, what the emergency response plan was, how long they expected it to take and what the expected spill into the river would be.
“We’ve been sampling the materials that have been going into the river … probably a half dozen times or so,” Stanley said. “It’s been liquid.”
The samples will be tested for the total suspended solids and biological oxygen demand according to the permit the regional district’s wastewater treatment facility has been given.
“We are testing it for the same things we would test it for when it is going out the regular outfall into the river,” Stanley said.
Although those results won’t be ready for a few days, the liquid has been coming out “quite clear,” said Stanley, and there is no smell to it. Some melt water and early freshet water have also significantly diluted the sewage water.
“The water itself seems quite benign, but of course, that will be either confirmed or denied as the lab tests come back,” he said.
There might be ramifications from the province, however. And, because the waters cross international lines, the province contacted Washington State and they will review everything that happened and file a response.
“At this point we just cannot say what the outcome is going to be because that is in their court,” he said.
By 6 p.m. Monday night some additional contractors — Chinook Scaffolding and Rossland Mechanical — were on site and a strategy was put into place to repair the line and replace the clamp.
However, the repair procedure was complicated, said Stanley.
“We had limited options because of the condition of the bridge so we couldn’t bring a lot of weight out, like a boom truck,” said Stanley.
Instead, around 7 a.m. Tuesday morning Chinook employees began construction of a hanging scaffold to reach the pipe where the leak occurred, hanging about 2.5 metres (eight feet) below the bridge deck out over the river.
Once that plan was approved by an engineer — as well as a safety plan that included a Fire Rescue boat downstream in the water — the scaffold was in place by 10 a.m. The pipe fitters began their work soon after and completed taking the clamp off around 11 a.m., placing the new clamp on, aligning the pipe and tightening it in by 12:30 p.m.
By 1:30 p.m., flushed with their quick success, the water was turned on to see if the repair was effective and the line held, said Stanley. The water conservation order that was put in place late Monday night was lifted by the time the afternoon rush hit the area.
The work crews could stay on the bridge for the next few days to complete visual inspections of the other clamps along the pipe, strengthening some clamped sections with tie backs.
“We think something might have changed on the bridge,” said Stanley. “It will be a preventative measure until we get the new pipe bridge built.”
In January, Trail and its regional sewer partners — Rossland and Warfield —decided to move forward with the creation of a pipe bridge to support the regional sewer line.
The approximate $2 million structure was deemed the most affordable option for rerouting the utility line attached to the closed Old Trail Bridge, which is considered condemned and will likely have to be torn down.
Last week Cordova Bay beach near Victoria was closed as crews cleaned up a 30,000-litre sewage spill and officials tested the area for contamination.