Determining the right sewer rehabilitation method for a given job is not always straightforward, as identifying a solution requires evaluating a pipe’s physical environment and condition. Without properly assessing these factors, municipalities risk only partially solving a problem with point repair. Or, an equally inefficient outcome, waste resources by doing more work than necessary with end-to-end repair. While some municipalities have rehab contractors that also provide consulting services to address what type of solution is best, at the end of the day someone must make a decision on how to repair the pipes. So what should be taken into account?
Understanding the entire pipeline’s condition will also influence what method is best when choosing between manhole-to-manhole and spot repair. The prevalence and pervasiveness of defects are important factors: In lines with fewer defects it may be easier and more cost efficient to target specific problem areas. Defects like roots, holes and cracks are all localized, which also makes them good candidates for point repair. Treating these small sections of damaged pipeline can also help avoid having to navigate bends and tapers that would otherwise present challenges during end-to-end repair. Assessing pipelines thoroughly before settling on a rehab method will help municipalities tackle sewer rehab strategically.
The service life of a pipeline should also be known before beginning rehab. If a line is slated for replacement or major rehab, then investing the resources to fix it manhole-to-manhole may not be the best option. Spot repair can act as a short-, mid- and long-term solution, whereas manhole-to-manhole repair is a big enough project that it does not make sense for many larger, still-developing rehab projects.
Sanitary Sewer Replacement image courtesy of Pam Broviak via Flickr (CC BY-SA 2.0)