THE VICTORIAN DESALINATION PLANT'S WATER TRANSFER SYSTEM

摘要

The Victorian Desalination Plant is the largest desalination plant built in Australia. The Public Private Partnership project was awarded to AquaSure in July 2009; AquaSure then contracted the Thiess Degremont Joint Venture to deliver the design, construction and commissioning. Thiess Degremont subcontracted the water transfer pipeline and the high voltage cables to a joint venture between themselves and Nacap Australia Pty Ltd, a specialist pipeline constructor. The design and construction began under an accelerated engineering, procurement, construction and commissioning (EPCC) program. The scope for the EPCC of the water transfer system began simultaneously with that of the desalination plant. The water transfer system enabled the desalinated water to be transferred from the plant in Wonthaggi to a Melbourne Water network connection at Berwick and, ultimately, to Melbourne Water's Cardinia reservoir. The scope of the EPCC included the approximately 2m-diameter mild steel cement-lined (MSCL) transfer pipeline over an 84km length with a capacity of 200 GL per annum; transfer pump station to convey up to 150 GL per annum; booster pump station; surge mitigation system to withstand pressures of up to 3,000 kPa and vacuum conditions; 87km of 220kV high-voltage below-ground electrical cables in trefoil configuration; two separate fibre optic cables and appurtenances along the pipeline easement. Precision planning by the project team was critical to the successful management of simultaneous challenges throughout the project delivery phases, including: 1. Implementing an intensive community and stakeholder engagement program to minimise the impact on the community; 2. Ensuring stringent environmental guidelines were achieved; 3. Undertaking a thoughtful procurement strategy and construction program to manage long lead items; 4. Completing engineering in accordance with project requirements and obtaining certification under an independent review process to allow procurement and construction to commence; 5. Ensuring the requirements of multifaceted durability were achieved; 6. Designing and implementing large-scale traffic management plans to ensure the smooth delivery of the many thousands of construction components and minimise impact on roads and traffic; 7. Planning for construction of the pipeline in flood-prone areas with varying geology, topography and conditions (such as acid sulphate soils) to ensure compliance with regulations. The approach taken by the multi-disciplinary team meant that the project was delivered to the highest quality, meeting contract and stakeholder requirements and with an outstanding safety record. This paper highlights the major challenges in delivering this critical infrastructure from engineering, procurement, construction and commissioning points of view.