Oily Water Sewer Trunkline Cleaning
Overview
A major U.S. refinery was experiencing chronic oily water sewer backups across multiple operating units. Believing the 28 inch trunkline had failed, the refinery was preparing to replace it at an estimated cost of $10 million.
Before the refinery committed to replacement, Motivo cleaned and inspected approximately 1,000 feet of the existing line. The work removed 124,000 pounds of accumulated debris and revealed that the pipe itself remained in serviceable condition. No lining, repair, or replacement was required.
The Challenge
The trunkline was a critical part of the refinery’s oily water sewer system. Years of accumulated debris had reduced its hydraulic and vapor capacity, causing repeated backups throughout the facility. Because the condition of the buried pipe was unknown, replacement appeared to be the safest path forward.
Replacing the line would have required a major capital project within an operating refinery. In addition to the new pipe, the work could have involved excavation around active units, contaminated soil management, utility conflicts, restoration, and operational disruption.
The refinery needed to determine whether the pipe had actually failed or whether accumulated material was preventing the system from functioning as designed.
The Solution
Motivo cleaned approximately 1,000 feet of the 28 inch trunkline over a three week period without requiring a facility shutdown. The cleaning process removed 12 vacuum boxes of debris weighing approximately 124,000 pounds.
Once the material was removed, Motivo inspected the cleaned pipeline to evaluate its actual condition. The inspection showed that the pipe was sound and could be returned to service without lining or replacement.
This stage gated approach allowed the refinery to base its decision on the condition of the cleaned pipe rather than assuming that recurring backups meant the trunkline had structurally failed.
The Result
Removing the obstruction restored the trunkline’s hydraulic and vapor capacity and eliminated the backups affecting the operating units. The refinery resolved the underlying problem for approximately $600,000 and avoided proceeding with the planned $10 million replacement project.
The work was completed in three weeks without a facility shutdown. The performance of the project team also led the refinery’s plant manager to issue a handwritten commendation recognizing the work.
A Practical Alternative to Premature Replacement
Recurring sewer backups can be caused by restricted capacity as well as structural failure. Until accumulated debris is removed, it can be difficult to determine the actual condition of the buried pipe or identify the appropriate solution.
Cleaning followed by inspection gives facilities the information needed to decide whether a line can be returned to service or requires localized repair, lining, or replacement. This reduces the risk of committing to a major capital project before the condition of the pipeline is fully understood.