SEWER LATERAL REHABILITATION
PROJECT NAME: SANITARY SEWER LATERAL REHABILITATION (EXCAVATION REPAIRS AND LINING)
LOCATION: VARIOUS ADDRESSES ACROSS THE CITY OF OTTAWA
OWNER: CITY OF OTTAWA
START DATE: MARCH 2009

The project was the City of Ottawa’s first contract calling for the CIPP rehabilitation of residential sewer laterals while also requiring spot repair excavations prior to lining.

Fifty addresses were selected by the City of Ottawa for this contract. Due to breaks and sumps, the sewer laterals could not be rehabilitated by CIPP without a prior spot repair excavation. Similarly, these laterals could not be repaired entirely by conventional trenching excavation methods for a number of reasons including the presence of trees. The City of Ottawa outlined specific requirements for each address in order to minimize inconveniences to the individual homeowners, and to minimize site disruptions and damages to surrounding trees and the surrounding environment, while at the same time minimizing overall costs.

In one instance, the sewer lateral ran under a cement porch, then under grass and under a large city tree before reaching the City main. There was a break in the pipe beneath the grass, including the presence of a highly invasive network of roots. There were cracks and fractures at various locations along the length of the pipe. The solution was to excavate and repair the break, and then install a CIPP liner over the entire length of pipe from the cleanout to the City main. In this case excavation was required because the liner could not be installed through the broken section, given that the stated obstacles could not be disturbed.

CWW engaged the services of a sub-contractor for the excavation portion of the project. The work was coordinated by CWW and involved first inspecting the pipe, locating the section of sewer that required excavation, spot repair, landscaping reinstatements, the rehabilitation by CIPP, and the final video inspection.