Orakei Main Sewer Rehabilitation MH1 - MH3 Utilising Spiral Wound PVC Lining
Annual Conference
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The Orakei Main Sewer MH1-MH3 section, constructed in 1959, currently provides local network storage and is utilised as an emergency overflow from Watercare Pump Station 64.
The concrete pipe had suffered mortar loss and corrosion, exposing the reinforcement bars and compromising the structural strength of the sewer. The pipeline is located in an upmarket Auckland waterfront district. Watercare decided that in order to satisfactorily rehabilitate the sewer with least disruption to the public, that an in-line rehabilitation process should be investigated.
Three rehabilitation options were presented at Tender Stage:
The tender evaluation process determined that the most cost effective option was spiral wound PVC lining. Following tender award, the project was delivered within 3 months causing minimal disruption to the local community and least impact to Watercare operational requirements.
This rehabilitation process has cost-effectively extended the life of the sewer section by 50 years. Upon completion of the project, the strength of the liner was verified by a water pressure test, the first time in Australia and New Zealand that a pressure test had been undertaken on a liner of this size in the field.