Boat anchor used to plug sewer pipe in Hannibal.
Members of the Hannibal Board of Public Works’ sewer department are no strangers to unplugging mains. But even they were surprised to find that a boat anchor was partly to blame for a sanitary sewer overflow (SSO) last month.
Vandals, who gained access to the sewer system by removing a 60-pound manhole lid, also stuffed carpeting and old tires into the sewer behind 1007 Paris Ave.
“That’s definitely stuff you don’t see in the sewer every day,” said Mathew Munzlinger, utility planning & construction engineer with the BPW, who cited roots as a “big cause” of sewer backups. “We’ll find sticks and stuff occasionally where somebody has stuck them down the pick hole in the lid and then they’ll get cross ways in the sewer and stop it up, but not the variety of debris we found this time.”
To help deter vandals the lid they had accessed has now been chained shut. The BPW has no plans to lock every sewer access point in the city, according to Munzlinger.
“We’ll do it just where the problem pops up,” he said. “If there’s not a need for the lids to be locked down then we’re not going to do it because it makes accessing the manhole that much more tedious.”
Munzlinger estimates the pipe that was plugged is just 6 inches in diameter.
“That’s not a very big pipe and it doesn’t take much to plug it up, plus when you block it it accumulates additional debris – toilet paper and what not.” he said.
The anchor-caused SSO resulted in approximately 50 gallons of raw sewage being released from the manhole and soaking into the surrounding soil. Munzlinger says the sewer could have been blocked for days before it was discovered.
While the BPW reports all SSOs to the Missouri Department of Natural Resources, it has not heard back from the DNR regarding any penalty that might be assessed as a result of the Paris Avenue overflow.
“I don’t anticipate (being contacted) on that particular one, but you never know,” said Munzlinger, noting that the amount of sewage that was released was not large.
Munzlinger is hopeful people will cease trying to plug up city sewers.
“Sewers are meant for only sewage, not these other types of debris such as grease, boat anchors, carpet ... that type of thing. They shouldn’t be placed down the sewer because of the consequences. SSOs and the serious stance the DNR is taking on them, it ultimately goes back to the rate-payer,” he said.