Technology Spotlight

What is your technology? 
The Sewer Line – Rapid Assessment Tool (SL-RAT®) is a preliminary inspection tool for gravity-fed sanitary sewer lines. It uses acoustics to estimate the blockage condition of the pipe. A speaker (transmitter) is deployed at one manhole and “yells” down the pipe to a microphone (receiver) that is placed at an adjacent manhole. The receiver has a reasonable expectation of how much sound energy should reach the other end, and based on this, provides a blockage assessment of the pipe. The assessment scores range from zero to 10, with zero being completely blocked, and 10 being an open pipe. The entire process takes less than three minutes, there is no flow contact, and results are displayed immediately. The devices also log GPS coordinates which can be downloaded with the results using a personal computer.

What are the benefits to implementing your technology?
This is a revolutionary concept. Significant resources are wasted cleaning pipes that do not actually need to be cleaned, but prior to the development of the SL-RAT® there was not a reliable means of rapidly assessing an entire length of pipe for blockages. Based on results from inspecting over 14 million feet of sewer lines, 70% of pipes on average receive a “good” score (seven or higher) from the SL-RAT®. The cost of doing acoustic inspections is 1/10th to 1/20th the cost of cleaning or CCTV inspection, so the potential cost savings (and more efficient use of resources) can be quite dramatic.

Has the technology been tested, demonstrated, or implemented to date?
We now have over 50 unique customers worldwide making use of the technology, and there have been multiple studies published regarding the use of the device. The U.S. Environmental Protection Agency released a report in June 2014 that studied the effectiveness and cost of using the SL-RAT®. Charlotte-Mecklenburg Utilities was our original development partner and currently owns 12 devices. Augusta, GA and Nashville, TN are two of the largest users. Augusta does all its inspection work using its employees, while Nashville subcontracts out all of its inspection work. Whether using direct employees or subcontracting the acoustic inspection work, customers are seeing dramatic cost savings and improved performance by making use of the technology.

What are the next steps needed to advance your technology?
Our device is commercially ready, so not much is needed in terms of technology development. The next steps are continued acceptance and use of our tool as part of an effective sewer line O&M program.

How has LIFT helped, or how can LIFT help?
Our biggest challenge is still getting utilities to integrate our technology into their maintenance programs. LIFT can help us identify trial partners who are interested in trying out newer technologies. The lessons learned from using a preliminary assessment program can be shared with other municipalities, which should shorten the time it takes for other customers to make effective use of the SL-RAT®.

For more information, contact George Selembo at