Sanitary Sewer Rehabilitation

Sewers are a series of connected pipes or pipelines that convey either wastewater or storm water to a designated downstream location for treatment and/or disposal. There are three different types of sewers: sanitary, storm and combined. Sanitary sewers and combined sewers convey wastewater from homes, institutions and businesses to a centralized treatment plant. Sanitary sewers carry only...

Sewers are designed to collect wastewater from intended sources and convey it downstream. However, some extraneous water may enter the pipes from unintended sources, either from surface water, groundwater through defects or direct illicit connection. Sewer defects are pipe system deficiencies resulting from system aging, structural failure, lack of proper maintenance, and/or poor construction and...

Sewer rehabilitation can be considered both repair and renewal, to reduce extraneous flow, and address structural defects. Rehabilitation is different from system replacement in that repairs selectively target I/I sources and structural defects rather than complete replacement of pipes and/or manholes. Not all sewer defects cause capacity restrictions or are considered I/I sources.

With a multitude of options available to rehabilitate sewers, the different conditions affecting the sewer should be considered before deciding on a rehabilitation method. Factors to consider when selecting a rehabilitation method include, but are not limited to the following:

Sewer pipe failure is most often a result of lack of maintenance. There are 3 stages of decay that warrant definition and are a direct result of I/I (See Figure 3).

Pipe linings are tight fitting and installed continuously from one access point to the next. Linings provide structural renewal of the pipe barrel, improve the performance of the existing sewer, and are appropriate for various pipe sizes and shapes.

In-situ spray or spun cast coatings or structural solutions may be used to extend the life of an existing sewer by increasing its strength or protecting the existing surface from corrosion or abrasion. Coatings also may be used to improve hydraulic performance

“Sanitary Sewers,” a 2011 fact sheet developed by the WEF Collection Systems...