ANDERSONVILLE — A pilot program to test underground pipe-repairing technology to avoid the removal of trees in Andersonville was not successful, the city said, forcing it to cut down 11 mature trees neighbors fought to save.
The city’s current method of replacing sewer lines requires digging trenches, often resulting in trees being cut down. After two years of testing one type of tree-saving, pipe-lining technology in Andersonville and elsewhere, the city said that method failed.
In the 12 locations where private sewer lines were repaired with the “inverted cured-in-place-pipe” method, known as CIPP, the technology failed in three cases, according to a memo the Department of Water Management sent to Ald. Harry Osterman (48th).
CIPP inserts a liner into existing pipes, sealing it from the inside to avoid having to replace long stretches of decaying pipe.
Because the sewer pipes cracked in three locations during pressure testing, all 12 sewer lines repaired using the technology will need to be replaced, according to the Water Department. That will require the loss of 11 trees in Andersonville.
Trees are being cut down this week on Balmoral, Summerdale, Berwyn and Farragut avenues, between Clark Street and Glenwood Avenue.
The city’s findings are a blow to residents who fought for the city to adopt the pipe-repairing technology that spared trees. But the pilot program — which has caused some Andersonville streets to be ripped up since 2019 — was not a total loss, according to the city. And it doesn’t spell the end for more tests of another type of cured-in-place pipe.
The inverted cured-in-place-pipe was only one of four tree-saving technologies tried out in the pilot program. Three other technologies proved viable, according to the water department. But the cured-in-place method was the technology tested most heavily in the pilot. It accounted for 14 of the 17 places the new methods were tested.
The city will continue testing the tree-saving technology in other parts of the city and make a full report when the pilot is completed, said Megan Vidis, spokesperson for the Water Department.
“The primary lining technology that was tested in the 48th Ward did not meet the standards necessary to reliably extend the life of the private [sewer] drains,” Vidis said in a statement. “However, some technologies tested were viable options to save trees.”
Water Department Commissioner Andrea R.H. Cheng, in her letter to Osterman, said a second type of CIPP technology is still being tested in Chicago. That method, called “pulled cured-in-place pipe,” requires workers to dig pits in two locations of the sewer pipe to insert the liner. In Andersonville, there was not enough room for two holes at most locations, so the “inverted cured-in-place pipe” method was used for the majority of the work. That only requires one pit.
Osterman, in a letter to constituents, acknowledged his frustration.
“Please know that I am as frustrated as you are with how this project has been handled, and, with or without the pilot program, this project should not have taken as long as it has to complete,” he wrote.
Tree-saving pipe replacement technology, including cured-in-place-pipe, has been used in many North American cities including Toronto, Rockford, Arlington Heights and Evanston. Cured-in-place-pipe is used in about half of the country’s pipe repair jobs, the CDC said in 2017.
But the technology has failed to catch on in Chicago.
In 2019, Andersonville neighbors and city officials began pressuring the city to try out the tree-saving pipe replacement method. A pilot program trying out cured-in-place-pipe on the Southeast Side in 2017 said it found water safety issues, but a Block Club investigation showed contractors called the pilot program itself “flawed” from the start.
City water officials never pursued the technology after the 2017 pilot, the investigation found. After hearing from neighbors, officials including Osterman, Ald. Brian Hopkins (2nd) and Andre Vasquez (40th) pressured the city to reconsider the tree-saving method.
The aldermen drafted an ordinance seeking the further study of the technology, but city officials in summer 2019 said a new pilot program would take place.
The pilot technology was installed in late 2019 and early 2020 and has been monitored since, according to Commissioner Cheng’s note to Osterman.
After coronavirus-related delays, a round of testing in May showed cracks in the lining of three pipes using the cured-in-place method. With the Illinois Department of Public Health, it was decided the 12 places where the faulty method was used needed to be replaced.
The two locations that used a variation of the pulled cured-in-place pipe method will remain for now as the city and state continue testing and monitoring, according to the memo.
Osterman said he will work to replace the trees lost in his ward due to the need for new sewer work after the pilot, and that he will also continue to push for the adoption of tree-saving methods in water main work.
“The results of the pilot are not what we wanted,” Osterman said. “For me it’s very regrettable and unfortunate. We need to make sure there’s clean water.”
Crews for the city will finish tree removal in Andersonville this week and then begin replacing the pipes where cured-in-place-pipe was used.
For neighbors who have been pushing for the tree-saving technology, the news that almost a dozen mature trees will be lost hits hard, said Andersonville resident Carolyn Bertagnoli.
The development comes as the city made a renewed effort to bolster its tree canopy, with the creation of an Urban Forestry Advisory Board passing City Council in June.
“These trees, they’re just beautiful,” said Bertagnoli, whose Summerdale block is set to lose five trees. “I wish a miracle would happen.
“They find money for a lot of things that are frivolous,” she said. “It’s not going to be the end of the world if they stop and give it another look.”
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