|
|
|
|
Innovative Sewer Replacement
Summer 2001 Older houses commonly have sewer problems because their sewer pipes are constructed of vitrified clay. The joints of the clay pipe are not watertight. Moisture from the pipe moistens the surrounding soil, which attracts tree roots. The roots grow toward the pipe and eventually squeeze into the joints. Inside the pipe, the roots trap solids and obstruct the flow of sewage. Toilets and sinks begin to drain slowly and may even appear to be plugged. As the roots thicken, they may crack the brittle clay pipe. Soil and rocks can fall through the breaks in the pipe wall and plug the line. Sometimes the root itself will grow so large that it will fill the entire sewer pipe.
Flushing copper sulfate through the sewer lines periodically can help while the roots are small. The chemical kills the portion of the root that it contacts and the dead portion of the root will break off and wash away. However, if the treatment is not performed consistently or if the roots get too big, the line may have to be cleared by a plumber. The pressure of expanding roots and the abrasion of the plumber’s equipment will take a toll on the pipe over time, eventually requiring it to be replaced. Often the old line can simply be dug up and replaced with a polyvinyl chloride (PVC) sewer pipe. However, sometimes digging up the old line is not feasible or desirable. For example, in our featured project, the sewer line was located under five beautiful trees. Digging up the old line would have been expensive and would have killed the trees or required a very expensive transplant project. The following photos show how "Pipe Bursting" was used to: 1.) prevent tree damage, 2.) to minimize yard disturbance, and 3.) to avoid disrupting existing utilities.
The new sewer line is a fairly flexible high-density-polyethylene (HDPE) plastic. The contractor laid out the pipe in 40-foot lengths in front of the house where it was to be installed.
The joints were squared-off and fused through a butt-welding process to ensure watertight, root-proof joints.
The long, thin, metal tube is a pneumatic device that functions like a jack hammer. The contractor placed the device inside the leading end of the HDPE pipe.
|
|
