Background

Of South East Water’s operational water supply network, approximately 620 kilometres of underground water pipelines are constructed from mild steel. The pipelines range from 225 to 2100mm in size with construction dates ranging from 1905 to present. The arrangement of the water mains makes them electrically continuous and, in most instances, are subjected to corrosion due to reaction with the environment, galvanic contact with dissimilar metals or as a result from stray DC current pickup (electrolysis) originating from train and tram traction systems

Contract Objectives

The outcome that South East Water is looking for is as follows:

• appoint a corrosion technical services contractor to assist with managing South East Waters existing pipeline corrosion mitigation assets and provide input into improvement initiatives.

Scope of Works

Ongoing maintenance and management of corrosion and corrosion mitigation is critical to the operational security of SEW’s buried steel water mains exposed to the risk of corrosion.

A number of assets associated with the mitigation of water pipeline and tank corrosion require monitoring and maintenance. The assets provide both corrosion mitigation and determining corrosion protection levels.

A summary of these assets are as follows:

• 35 pipeline Impressed Current Cathodic Protection (ICCP) systems.

• 15 water tank ICCP systems.

• 1800 pipeline monitoring test points comprising of sacrificial anodes, drainage bonds, continuity bonds or electrically isolating flanges.

The role of Corrosion Technical Services Contractor is to provide technical assistance delivering SEW’s corrosion strategy to ensure the risk of water main or tank failure is minimised by preventing or reducing corrosion rates. Through inspection, monitoring and testing, recommendations may include to undertake immediate CP restoration, maintenance, further investigations, recommend isolations / bonds, system upgrades, or application of CP to pipes that have been identified as having no supplementary corrosion protection.