New Castle County Sewer Inspections

New Castle County, Delaware

Working under an open-end contract, KCI is responsible for managing sanitary sewer investigations for New Castle County, Delaware. As part of this agreement, our team identifies, evaluates and implements new and emerging technologies that can help the sewer maintenance department operate more efficiently. KCI conducted a pilot study to evaluate the Sewer Line Rapid Assessment Tool or SL-RAT, that uses acoustic-based technology to detect blockage conditions in gravity-fed sewers.

In order to keep these networks functioning properly it’s essential that utility and maintenance crew’s regularly inspect and clean the lines. Previously, New Castle County set their routine maintenance frequency based on the total miles of pipe and the required amount of cleaning based on regulatory requirements. However, KCI recognized that this method wasn’t effectively maximizing the county’s resources. Our team worked closely with officials to test the new inspection tool for its potential to help prioritize sewer cleaning resources and operations.

Placed over top of two adjacent open manholes, the SL-RAT transmitter sends an acoustic signal down the pipe, and a receiver listens and interprets the sound. The technology measures the dissipation of sound energy in the airspace between the two units. Any obstructions within the pipe like roots or grease will block the sound waves and create an energy gap.

Part of the pilot study involved evaluating what percentage of the county’s pipes were actually in need of cleaning using a sample of their entire network. Our team assessed over 56,000 linear feet of sewer lines. Without the acoustic analysis, the county would have spent time and money cleaning all of these pipes as part of their regular maintenance schedule, but ratings from the SL-RAT revealed that only 10 percent of the pipes required immediate action. By using the tool, New Castle County can easily determine where they need to focus their resources and operations, and eliminate unnecessary cleaning.