Fraser – Macomb County Public Works Director Candice Miller said Wednesday a backup of about 1.5 million gallons of sewage into a trench at the site of a sinkhole repair was a “slight setback” but stressed “the system worked as designed.”
Sometime between 10 p.m. and around midnight Monday, a trench being used to repair the 15 Mile sewer near Hayes filled with sewage, Miller said at a press conference. She said about nine feet of sewage filled the bottom of the trench and later dropped to about six feet.
“Fortunately no one was in the trench at the time – there were no injuries and none of it was released to homes in the area,” Miller said. “It all was contained to the immediate area – as it was designed – and is being pumped out and returned to the sanitary system further downstream.
“It’s too bad but not that bad of a setback,” she said. “We are still on track on the project and have not had to seek additional funds. But most importantly, it was not a safety problem for workers or citizens.”
Three vehicles were submerged in the sewage: a small tractor, an excavator and a vehicle called the Batmobile, which is used to insert new pipe into the existing sewer line. It was not immediately clear if any of them will be returned to use.
On Dec. 24, 2016, the Macomb Interceptor Drain at the location collapsed, causing a 100-foot wide, 250-foot long sinkhole and prompting the evacuation of 22 homes in the area. The repair project, expected to be completed next month, is pegged at about $75 million.
Miller said cameras were being placed throughout the trench system to determine what caused this week’s sewage backup. The county public works department collected 100 samples of water from collection points around the trench and found no contaminants.
“Our engineers have only just now been able to physically get down into the trench and assess the situation,” she said. “Once we have their full report, we will be able to determine how this incident will impact our schedule. It is our hope and our belief that, while serious, this setback will not prevent us from completing this project to the point where 15 Mile Road will still be re-opened sometime in December of this year.”
About 3,000 feet of the total 4,000 feet of pipe that was being put in place at the repair has been installed, Miller said. A new timeline estimate for completion of the new pipe installation will be developed over the next several days.
“We’re hopeful that the fact that we were running under budget so far will still allow us to complete this project within our anticipated budget of $75 million. We will know more by the end of the week,” she said.
The pump-out of the trench is expected to be completed this week and is being routed to a sewer line downstream.