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CIPP Lining A Cost-Effective Solution For Corroded Concrete Pipes
Utility districts understand that water and sewer pipes deteriorate over time. This is especially true for concrete pipes. Popular for water systems, pre-stressed concrete cylinder pipes have also been installed in sanitary sewer systems. But an inherent issue with sewage is the build-up of hydrogen sulfide (H2S) gas, which can have far-reaching effects that may not be noticeable until a major problem occurs.
The Caledonia (WI) Utility District faced such a problem with a section of pipe. As they investigated the issue, their findings could be helpful for any sewage district that uses concrete pipe for sewage collection.
The Village of Caledonia is a quiet community of 25,000 residents approximately 20 miles southeast of Milwaukee, WI. Tucked between I-94 and the city of Racine, the village has no treatment facility. Instead, according to Robert Lui, manager of Caledonia’s Utility District, all 175 miles of pipe are used for collection. The pipes empty their effluent into the treatment facility in Racine. Installed in 1988, the collection system uses pre-stressed concrete cylinder pipes that range from eight to 52-inches in diameter, and includes two lift stations. Most of the pipe operates on gravity flow, but the last 10 miles is a force main operating at 20 – 22 psi, Lui said.
In June 2008, a 10 by 14-foot sinkhole appeared on Michigan Boulevard, along Racine’s lakefront. Because the hole occurred above a portion of the force main, Racine officials contacted Caledonia’s Utility District. Inspection revealed a large hole in the force main, and that a chunk of the pipe and a large amount of surrounding sand had washed down the main. (There was no apparent exfiltration, Lui added.)
Caledonia’s staff cleaned out what they could from the broken pipe, ultimately removing about five yards of sand, dirt and debris. But they stopped when their equipment encountered a large boulder that was protruding into the pipe. The district turned to Reesman’s Excavating & Grading Inc. from Burlington, WI, to perform an emergency repair of the pipe and pave over the hole in the road. “That was a temporary patch to buy some time to figure out what we were going to do with it,” Lui said.