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06/07/2006: "Smoking the sewer lines is not some druggie vernacular"

“Smoking the sewer lines.”
Sounds like some covert language used among druggies.
Actually, the two days early this week that was spent “smoking the sewer lines,” the city maintenece workers and a few helpers, were doing just that -- running smoke through the city sewer lines.
“Doing this tells us if there are broken sewer lines in the system,” said Jim Heyen, from Wahoo, who is a wastwater technician with the Nebraska Rural Water Association (NRWA).

“If there are cracks or holes in the lines, it can be allowing a lot of unwanted water to come into the wastewater treatment plant, which in turn will overburden the treatment plant,” Heyen stated.
According to city water superintendent Leon Wakeley, the line that feeds all the city’s wasterwater into the treatment plant normally runs at about a fourth of capacity.
“But when it rains,” Wakeley noted, “that flow becomes three times as much,” meaning there is a lot of water enterting the sewer lines of the city through cracks and holes.
The MWRA offers the sewer line smoking service for free to its members. The only cost to the city is the smoke bombs that are set off when the operation is being conducted.
“Our membership dues are only $150 a year,” stated Wakeley. “Just being able to have this done makes membership in the association well worth the cost of the dues.”
For two days this week, city employees accompanied Heyen around the streets of the city, stopping at every manhole. Each manhole was removed, and Heyen placed the smoking machine over the manhole.
He then fired up the machine, fired up a large smoke bomb, and set it to smoking right next to the smokie machine, which is essentially a large-scale blower.
The smoke is forced down into the sewer lines running up the streets and into each home that is served by that particular line. Everyone involved in the project walked around checking out each home’s sewer ventiliation pipe somewhere on the roof.
If their sewer system was operating properly, smoke would come pouring out of the roof vent. If it wasn’t, more than likely, that home had problems with its sewer system and they also had some smoke seeping into the home.
The smoke is not harmful to people, but is accompanied by sewer smell. It dissipates in just a few minutes.
But that signals a problem for that homeowner.
So how does smoking the sewer lines show where cracks or holes are in the lines?
The smoke actually rises out of the crack or hole, and seeps up through the ground, emerging right above the trouble spot with a hazy ball of smoke thick enough for workers to see.
The trouble spot is noted, and will eventually be repaired.
Each smoke bomb lasts about three to four minutes, and can wind its way through three to four blocks of sewer lines. Heyen said each individual smoking takes about 10 to 15 minutes to complete.
The process can be used to find leaks in water lines, too.
“Some of these lines are up to 80 years old,” Heyen said, “and like anything that old, they eventually wear out and develop cracks and holes.”
Heyen said a small crack in a sewer line can allow enough excess water to slip in to double the amount of water in the lines. He said a one-inch wide hole in a water line will cause a loss of 200 gallons a minute ... that’s a loss of almost 29,000 gallons of water a day!
A leak like that can cause the cost of water to skyrocket, and there’s no way of recouping that loss because that’s water which is unmetered.
With sewer systems, it’s not how much is going out, but how much water is leaking in. The more unnecessary water that leaks into the sewer system, the harder it has to work, and thus costs go up and maintenance is needed more frequently.
“We want your wastewater treatment plant to be treating city sewage, not the rainwater that comes into the pipes from the ground, or sump pump water,” Heyen stated. He noted that residents who illegally let their sump pumps dump water into their sewer system, are causing the city to spend a lot of extra money to treat clean ater.
Heyen said the NRWA provides smoking services to around a dozen towns each year.
“We recommend that cities and small towns do the smoke checks at least every three to five years,” Heye noted. “They should do it right away if they notice a large jump in the amount of water thatgoes through their wastewater system.
“We always now when we’ve got a problem,” said Wakeley, “Because the production at the treatment plant goes up instantly.”
After a half a day of smoking the sewer lines of Crofton, a couple problem spots had been found. An oficial report will be filed with the city, and each trouble spot will be repaired.
So perhaps you could almost imagine ol’ Cheech and Chong mumbling those words, “Hey man, let’s go smoke the sewer lines.” But thankfully for those two famous druggy comedians of the 1960s and 70s, they never found any places where the smoke leaked out, and hopefully, neither did the city of Crofton.