Technology Demonstration: Acoustic Condition Assessment of Wastewater Collection Systems

The overall objective of this EPA-funded study was to demonstrate innovative sewer line assessment technologies that are designed for rapid deployment using portable equipment. This study focused on demonstration of technologies that are suitable for smaller diameter pipes (less than 12-inch diameter). Recently developed and commercially-available acoustic-based sewer pipe assessment technologies demonstrated during this study were the Sewer Line – Rapid Assessment Tool (SL-RAT™) manufactured by InfoSense, Inc. (InfoSense) of North Carolina and the SewerBatt™ manufactured by Acoustic Sensing Technology Ltd (ASTL), based in the United Kingdom.These technologies can provide a rapid assessment of the need for pipe cleaning and an overall pipe-condition assessment. Acoustic technologies require a minimal amount of equipment when compared to traditional closed-circuit television (CCTV) inspection systems. These acoustic based technologies have the potential to provide information in a matter of minutes to assist an operator in determining whether a sewer pipe might be partially or fully blocked and require cleaning or renewal. The speed of the assessment, using minimal equipment, has the potential to result in significant cost-savings compared to traditional methods, such as CCTV inspection. It is generally known that smaller diameter pipes (i.e., less than or equal to 12-inch diameter) contribute to over 90 percent of the sewer main backups reported in a typical city (Sprague, J., 2007). This study hence focused on the demonstration of acoustic technologies that are suited for smaller diameter pipes.This collaborative field demonstration of the SL-RAT was led by EPA’s National Risk Management Research Laboratory (NRMRL) in Cincinnati, Ohio. EPA worked with the Metropolitan Sewer District of Greater Cincinnati (MSDGC) as a collaborative research partner to identify study locations, provide access to the study area sewer lines and to perform the related field work. Specifically, the data and information obtained from the following technologies were used in this demonstration project: SL-RAT; SewerBatt; Pan-Tilt-Zooming pole-mounted camera (aka “camera on a stick”) manufactured by Envirosight Quickview; and HD-digital scanning CCTV or the PANORAMO 3D Optical Pipeline Scanner manufactured by RapidView-IBAK.The results of this demonstration of the SL-RAT and the SewerBatt show promise for the application of these technologies as tools for cost-effective, pre-cleaning assessment, post-cleaning quality assurance and quick condition assessment screening. The application of these technologies in an overall collection system O&M program should enable wastewater utilities to optimize their sewer cleaning efforts and free up valuable resources to more effectively implement critical CMOM and asset management programs.