Diagnostic techniques for sewer systems

The National Research Council Canada (NRC) has recently completed a project to assist the City of Montreal in determining the condition of its water and sewer system. NRC staff members reviewed available and developing diagnostic techniques for both systems, conducted experiments on non-destructive evaluation methods and provided general scientific advice during the course of the project. This paper presents a review of current technologies for inspecting brick, concrete and vitrified clay sewer systems, including the results of three experimental investigations. The results of the review are given in a tabular form that lists the applications, advantages and disadvantages of each technique. Current and developing technologies are described that will supplement or replace closed circuit television inspection for determining the condition of sewer pipes through inspection of their internal pipe walls. In addition, techniques that allow sewer operators to investigate the pipe wall condition throughout the wall’s thickness (rather than just on the inner surface) and determine whether voids exist behind the pipe wall are described. (Published in Journal of Infrastructure Systems, May 1999) 2