Water Journal : Water Journal February 2013
54 Feature Article WATER FEBRUARY 2013 through ow-on demand from a new workforce for housing, products from local suppliers and additional business for retailers and service providers. During construction, local people were employed wherever possible. In addition, more than $500,000 was invested by AquaSure and TDJV in local community support programs, and many new jobs were created within Victorian businesses contracted to provide goods and services to the project. Following community concern about how the project would impact the rental market TDJV, together with the Bass Coast Shire Council, developed a Housing Accord. A new pool of accommodation was made available through holiday homes and investment properties that had not previously been available for rent and those properties were the only properties promoted to employees. ON THE GROUND On the pipeline and power supply easement, 11 crews worked in various locations between Wonthaggi and Berwick, including two mainline crews for long, straight runs of pipe, two smaller mainline crews specialising in dif cult terrain, three 'special crossing' crews for road and river crossings, three pipe jack crews and a valve installation crew. Central to this work was smooth operations between the construction team and the wide range of stakeholders impacted by these works, among them three Councils, road, rail and environmental authorities, utility providers, as well as 125 directly affected and 400 indirectly affected landholders. A dedicated team was established to maintain relationships with individual landholders and work with them to complete land surveys and property condition reports, as well as negotiate access to properties to allow construction work to occur. The team worked closely with farmers to minimise impacts on cropping and livestock. A Traf c Management Liaison Group met monthly with representatives from Cardinia, Casey and Bass Coast Shire Councils, Vic Roads, Thiess Degrémont Joint Venture, Pipeline Joint Venture, Department of Sustainability and Environment, and Victoria Police to develop and discuss traf c management strategies. UNDERGROUND ASSETS The plant connects to the existing electricity grid at Cranbourne, some 87km to the north-west, by means of a high voltage alternate current (HVAC) underground cable. The cable is co-located underground in the same easement as the transfer pipeline. Underground power was the preferred outcome for the project as it has the least impact on landowners and people living and working in the area and this was a major concession to community concerns early on in the project. The plant and transfer pipeline's operating power requirements are 100% offset by renewable energy. KEY LOGISTICS OF THE PROJECT QUANTITY OF EQUIPMENT REQUIRED The quantity of materials required was substantial and included 72 pressurised lters, 51 RO trains ( rst past and second pass), 15,000 valves, 500 pumps, 200,000 tonnes of concrete and 750km of electrical cable. To manage such a scale, equipment standardisation and off-site fabrication was essential to reduce the construction duration and facilitate mechanical and electrical erection. Logistics such as oversize road transportation had to be well managed. One instance of this was the transportation of 72 massive Dual Media Pressure Filter vessels, which form part of the pre- treatment process. Each vessel measures 15 by 4.6 metres and weighs more than 50 tonnes. They were manufactured in China and transported to site from the Port of Melbourne in a series of overnight operations between September and December 2010, with up to four vessels moved at a time as part of convoys more than 500 metres long -- one of the longest ever approved for transport on Victorian roads. Speci c infrastructure had to be designed and built to accommodate the plant's prefabricated modules. The common structures were designed for the nal plant capacity of 200GL/y: two 4m diameter tunnels (for a cumulated length of 2.5km); a 1,000ML/d brine diffusion system; a 1,500ML/d lift pumping station; two 35,000m3 storage tanks based on soft bladder technology; an 87 km 220 kV AC underground cable; and an 84km 1.93m diameter cement lined steel pipeline. LOOKING TO THE FUTURE With RTF now complete, water production has ceased and the plant has been put into standby mode. The plant is now in the hands of the operations team, DTSJV, which will manage it until 2039 when it will be handed back to the Government in perfect working order, and without further capital cost to the consumer, ready to produce high quality drinking water for decades to come. In standby mode the full complement of the Operations and Maintenance team, comprising 52 people, ensures the plant remains in full working order, and ready to deliver on demand water security for Victorians of up to 450,000m3 of potable water per day. During this period, water is able to be transferred in reverse ow from Cardinia Reservoir in Melbourne to the various connected water authorities along the pipeline if required. The water quality in the pipeline is continuously monitored by the Operations and Maintenance team as well as DSE and water authorities. With key components of the plant having a design life of 100 years, whether it's operating at full capacity or in standby mode, the Victorian Desalination Plant will be able to produce high-quality water to meet the needs of generations of people in times of drought. WJ Inside the VDP's reverse osmosis building.
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