Large Pipe-Cleaning System Tackles Nashville Challenge

By Jeff Griffin, Senior Editor | November 2012, Vol. 67, No. 11

On average, the Hyjector will consume in excess of 200,000 gallons of water per day, says Schotthoefer.

“Using fresh water would place an additional burden on the wastewater treatment plant if they were tasked with treating this increase in wastewater due to the cleaning,” he explains. If the municipality is under drought conditions, cleaning could prove costly because of the potable water consumed for cleaning. Recycling water not only prevents wasting fresh water and reduces residential inconvenience, it also enables us to clean an entire waste stream with no need to bypass pump, plug or shut the system down. Without using neighborhood hydrants, complaints of low pressure and brown drinking water or the potential repairs that will be needed for the water main after usage-related stressing, are eliminated as are costly traffic detours or other inconveniences to the residents, such as lengthy road closures due to excavations for repairs.”

Schotthoefer said the equipment is designed and manufactured by Doetsch and is in a constant state of innovation.

“We have not yet encountered a project that did not require equipment modifications as well as special fabrications to overcome new challenges,” he added. “As we are exposed to more difficult projects, our labor and equipment continues to reach new levels of service excellence.”

Cleaning of the 9,000-foot section was completed in six months.

“More than 1,500 tons of debris was removed from these segments. CES performed the long reach final inspection using a combination of sonar and CCTV. The survey revealed that there was less than three tenths of one percent debris remaining impacting flow capacity,” Schotthoefer said.

The project was the first time the city of Nashville had used the Doetsch cleaning method.

“We had our doubts on whether or not the pipe could be cleaned given the long distances and depths of the line,” said Joe Atol of CES. “Doetsch convinced me they could clean the pipe after numerous site visits and conversations. We submitted our plan to Nashville Metro and, once approved, manufacturing of the equipment began. After all the obstacles, I was very pleased Doetsch was able to clean the pipe ahead of schedule, and CES was able to inspect the long distance."