Programs undertaken by Water Utilities to rehabilitate existing sewer catchments are typically designed to restore the structural integrity of deteriorated sewers and / or reduce infiltration / exfiltration (I/E).
Monitoring of the effectiveness of sewer rehabilitation programs has shown that achieving I/E reduction targets often requires more than just lining of deteriorated sewer mains. Five areas need to be comprehensively addressed:
For more than the past decade Water Authority projects for the rehabilitation of deteriorated sewers by lining have included requirements for sealing of lateral connections. In this time the technology has developed from the early days with solutions that were shown to offer insufficient working life, through to a couple of generations of development of solutions that were progressively more effective and more practical to install.
Rehabilitation of maintenance holes is featuring more prominently in rehabilitation programs as the effects of deteriorating structures comes to be better understood. Lining of house service lines has always been plagued by questions of ownership and responsibility, but there is now the recognition of the contribution they make to infiltration into a sewer system.
This paper details latest developments in these technologies and how they are being effectively employed.