Fort Worth Launches Unique, Aggressive Sewer Inspection/Cleaning Program

By Jeff Griffin, Senior Editor | July 2011, Vol. 66 No. 7

The city of Fort Worth, TX, sanitary sewer system serves 22 communities with a total population of more than 900,000. It contains approximately 3,011 miles of underground pipe infrastructure that collects and carries an average of 108.5 million gallons a day to the Village Creek Water Reclamation Facility.

As with all cities, maintaining sewer infrastructure is a never-ending and costly task. One key to keep piping in good condition is acquiring and analyzing accurate data about its condition in order to anticipate potential problems and address them in a timely manner.

To accomplish this, Fort Worth is committed to a multiyear inspection program for all sanitary sewer lines of 24 inches in diameter and larger. However, Fort Worth’s approach to inspections is different than typical programs which clean sections of pipe, then conduct inspections with closed-circuit television (CCTV) cameras.

The city has reversed the process, inspecting pipes before cleaning. Fort Worth’s inspection process for large-diameter sewer pipes is more comprehensive than simply using CCTV video; instead, it employs high-definition video, laser profiling and sonar, then cleans only segments needing attention.

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To implement these assessment technologies, the Fort Worth Water Department (FWWD) developed and initiated the Interceptor Condition Assessment Program (ICAP). Under the program, the city has committed to a multiyear plan to inspect all of the sanitary sewers that are 24-inches in diameter or larger.

Inspection
Darrell Gadberry, FWWD field operations division regulatory and environmental coordinator, said conventional CCTV inspections can identify defects such as cracks, breaks and roots, but does not provide a means of evaluating the severity of wall loss due to corrosion. To do that, the only option has been to excavate, take core samples, repair the pipe and restore the site, a costly and time-consuming process.

“The recent introduction of 3-D laser technology for large-diameter sewers demonstrated the ability to solve this problem,” he explained. “Coupled with high definition television (HDTV) inspection and gathering sonar data, the FWWD recognized ways to overcome the inefficiencies associated with the conventional approach used throughout the industry for assessing large-diameter sewer pipes.”

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