Sanitary Sewer Cleaning Prioritization and Scheduling


  • Vivek Sai PE - Hazen and Sawyer

Like many municipalities, Jefferson County, within its 3,100 miles of sewer collection system experiences blockages due to grease, roots, rags and various debris in the sewer lines. These blockages can cause or exacerbate overflows in the sewer system and also cause home backups. Given the limited O&M County personnel for such a large area and the length of time it takes to clean every pipe in the system on a routine basis, it is extremely important that the County prioritize cleaning areas and clean them proactively to prevent blockages.

One of the goals within Jefferson County, Alabama’s Asset Management Program (AMP) is to cost-effectively minimize O&M related overflows and home backups in a way that targets cost and personnel where they have the highest benefit.

Prioritization of which pipes need to be cleaned and setting their re-cleaning frequency is very important to have an effective preventative O&M program. Hazen and Sawyer has developed a GIS-based model to identify pipes/areas that need frequent cleaning to alleviate these spills. Several parameters such as historical overflow data, customer complaints, and O&M codes from CCTV Inspections is input into the model. The model identifies areas that have O&M related issues. Work orders are created in Cityworks (CMMS system) to clean these pipes.

The County has plans to purchase the Sewer Line Rapid Assessment Tool (SL-RAT) equipment, which uses active acoustics to determine blockages. These will be used to provide a quick blockage assessment before cleaning and quality assurance checks after cleaning. This will help to save time, money and county’s resources for pipes that do not need cleaning, help reduce cleaning frequency and set up a baseline number for a “clean” pipe.

For more information, please contact the author at

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