The Central Davis Sewer District (CDSD)  is a publicly-owned collection system and water treatment plant that serves three local cities in Northern Utah. With a new highway being constructed just outside their facility, there was a need to have a new pump station installed on the premises. After installation of the new pump station, it became apparent that there was a large leak in the manhole chimney which caused it to fill up with about 10’ of water.

 CDSD contacted PolyFoam Solutions, a local geotechnical contractor to see what could be done to seal the leaks. After pumping water from the manhole it was obvious that two of the manhole’s horizontal joints had large leaks and were infiltrating about 10-15 gallons per minute of water into the pump station.

 PolyFoam Solutions devised a plan to seal the large leaks using AP F400, a flexible polyurethane grout. During the project, approximately four holes were drilled around the lower manhole joint and injection ports were installed. The polyurethane grout was pumped into the ports and began to travel around the joint sealing the leaks. Oakum was utilized to temporarily seal the larger leaks until the grout had time to cure. Once the grout had traveled as far as it could from one port, the technician moved onto the next port until the entire joint had been sealed water-tight. The upper joint only required 3 port injections due to how well the grout traveled. The project only took about 3 hours to completely seal all of the leaks and return the manhole to service.