New Berlin - Ever wonder what's down a manhole?
Chris Stamborski, assistant director of municipal services for R.A. Smith National, knows. He is a consultant who helps New Berlin with any sticky sewer problems. He is currently working with the city on replacing sewer laterals, pipes that take waste water from homes to sanitary sewers in the streets.
Manholes are critical to keeping those sewers in good operating condition. New Berlin has roughly 5,000 manholes, he said. Sanitary sewers carry waste water from homes and businesses to sewage treatment plants. Generally speaking, some manholes also are for storm sewers and others are for fiber optics, he said. In downtown Milwaukee, manholes give access to steam tunnels.
One might wonder if workers have to climb down into a sewer and stand in sewage if a sanitary sewer needs maintenance. Not so, Stamborski said.
Not in sewage
"They are standing on a bench above the sewage," he said.
While some manholes do have ladders, "Rarely do they have to climb down," Stamborski said. "Most things can be done from on top."
Maintenance is the usual task. Then workers lower a hose with a jet spray to flush debris downstream where it can be pulled out with a vacuum, he said.
That should be done at least every five years, he said. New Berlin tries to get at it more often.
Older manholes are made of brick. New Berlin is a newer community so its sewers are usually made of concrete, Stamborski said.
Perhaps surprisingly, water in the sewers is normally gray, he said. Organic matter and toilet paper lose their identities in only two or three blocks of passage through a sanitary sewer, he said.
City sewers underneath the streets in New Berlin neighborhoods are usually eight-inches across, he said.
"About 200 homes can connect to an 8-inch pipe," Stamborski said. More homes than that need a 10-inch sewer pipe.
Manholes are generally found where sewers turn, he said. They help workers know where the sewers are.
"Otherwise, you need really good records of where the pipes are," Stamborski said.
If a sewer pipe is straight, you will find a manhole 400-feet apart at the most, he said.
Manholes go down to different depths, but all are below basement level. That's because sewers rely on gravity to bring the flow along to its final destination at a sewage treatment plant, he said.
Manholes are hundreds of feet deep close to the Jones Island treatment plant in downtown Milwaukee, even though they look like any other manhole, he said.
"Then they call it a shaft. No man is going down there," he said.