Who you gonna call?
As a camera mounted on a wheeled robot maneuvers its way through the dark, wet labyrinth of Gothenburg’s underground pipes, a grating voice announces “severe groundwater, severe groundwater.”
“That’s Sewer Sally,” Larry Kramer says with a laugh.
Sewer Sally is the voice that repeats what Johnson Service Company employees type on a computer for a video they are creating for the City of Gothenburg.
Live footage shot by the camera shows the location and severity of sewer problems on a computer screen inside a van.
Those images are transferred to DVD and to printouts, along with other information, for city engineers and officials to study.
From what the robotic camera films inside pipes, she loudly declares when and where problems occur.
The infiltration of groundwater is one such problem in Gothenburg.
Kramer is foreman for the company the city hired to film the inside of sewer main. He points to groundwater gushing through a cracked pipe in the west Fourth Street area.
“Roots have caused groundwater infiltration problems here,” he said.
For the past several years, several residents have complained of sewage in their basements following heavy rain.
City officials have blamed the problem on the city’s aging sewer system, which is cracked in places, from roots and groundwater, and plagued with the buildup of sediment and other debris.
Last November, Gothenburg’s city council accepted a $46,500 bid from Johnson to clean and film the sewer in areas where sewage problems occur.
A council priority is to repair those areas as the budget allows since the work is expensive.
Last Thursday, Kramer and his crew were cleaning debris on west Fourth Street.
One employee vacuumed debris from the sewer through a manhole while another worker operated the robotic camera through the sewer from another manhole behind the debris cleaner.
The upstream sewer was plugged to keep water from the cleaning process downstream.
Kramer noted that the west Fourth Street area has high infiltration of groundwater because of deteroriating pipe. Roots and other debris makes the process slower.
“We like to get about 3,000 feet down in a day but are averaging only about 1,800 feet,” he said, noting that the robotic camera moves about 30 feet per minute under ideal conditions. “That’s because the lines are dirty with sand and grit.”
In addition, he noted that the deeper the sewer, the more problems with groundwater infiltration.
“We never know what we’re going to see,” Kramer said, noting that roots and cracks in the lines are the most common problems.
Once problems and locations are identified, Kramer said communities usually fix problems through sewer lining or pipe bursting.
The first method is the most popular, he said, because it’s less costly than pipe bursting.
A liner is installed through a damaged sewer, manhole to manhole, to restore structural integrity and restrict the intrusion of roots and groundwater.
Pipe bursting involves the replacement of a sewer main through an expanding device that travels through the pipe, breaking it into small pieces that are shoved into the surrounding soil, Kramer said.
New pipe is then attached to the back of the expander head which replaces the line immediately.
With aging sewer and water mains in many communities, Kramer said his company is booked until August.
“It’s big business,” he said. “People can get grants which makes it easier for them to work on infrastructure.”
However sewer and water lines sometimes get put on the back burner until problems occur, Kramer pointed out, because “out of sight, out of mind.”
Sales and operations manager Lewis Hyatt said preventitive maintenance saves money in the long run, noting that his company has such a program in which sewers are cleaned and treated on a yearly basis.
“If you’re reactive, it typically leads to more costly repairs,” Hyatt said.
Johnson Service Company employees began work May 25 and plan to finish during the second week of June.