Cleaning Large Diameter Interceptors: Everybody Knows They Need to Do It, but Doesn't Want to Admit It

The maintenance and cleaning of large diameter sewer pipes is a project many sewer utilities know they need to undertake, but because it is challenging and costly it is often relegated to a lower priority in exchange for more manageable and pressing maintenance activities. Challenges to completing a successful cleaning program include: having a good understanding of the condition of the pipe, knowing how much sediment or debris has collected in the sewer, the type of debris (compacted, rocks, bricks, etc.), development of a set of appropriate specifications, and quality-checking the work of the cleaning contractor to make sure the sewer is in fact cleaned. The Sanitation District No. 1 of Northern Kentucky used pre-cleaning inspection data and model simulation to target their effort in a large diameter interceptor cleaning project, resulting in a significant reduction in cost with minimal projected impact on the benefits of cleaning. A qualifications-based bidding process, a clear and verifiable cleaning standard, and a partially automated QA/QC process further contributed to keeping costs down and making the project successful.