Water Infrastructure Group successfully rehabilitated two sections of Sydney Water’s Northern Suburbs Ocean Outfall Sewer (NSOOS).

The rehabilitation was completed on schedule using a two-part epoxy mortar coating system that the company has refined to be an extremely efficient, reliable and safe option for sewer rehabilitation.

The process was originally developed by Water Infrastructure Group for rehabilitation of Sydney Water’s Southern and Western Suburbs Ocean Outfall Sewer, which is the largest sewer rehabilitation project ever undertaken in Australia.

Water Infrastructure Group Project Engineer Moyra Martinez explained that the NSOOS project involved rehabilitation of two aqueducts located in Gore Creek Reserve and Burns Bay Reserve.

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Mr Martinez said “The primary intent of the rehabilitation work is to apply a protective coating to preserve the remaining concrete in the roof soffits and walls. We have developed an automatic pump system that ensures that both hardener and base component are mixed at the right ratio, pressure and temperature to achieve a very high quality finish. We successfully applied a 20 mm coating over a 1,500 square m area for this project.

“The work was undertaken in normal live flow conditions. The advantage of our pump system is that it draws the two-part epoxy from 1,000 litre bulk bags on the surface through 100 m hoses so that only the spray applicator is within the sewer.

“To provide safe working areas, we designed custom access platforms to minimise hydraulic resistance. Safety is our highest priority for this type of work and this innovation in conjunction with our safety and environmental systems has given us outstanding results for Sydney Water’s safety audits,” Mr Martinez said.

Completed as part of the SewerFix Wet Weather Alliance, the sewer remained fully operational during the rehabilitation with minimal disruption to residents.