Water. Desalination + reuse
Issue link: https://fhpublishing.uberflip.com/i/724419
14 On Site September 2016 Water. desalination + reuse The two-pass RO plant has three separate streams The soluTions • Site chosen from a shortlist of four for its ready access to high activity ocean water • The plant can operate as three separate 50 gigalitre facilities, giving a high degree of flexibility in production • A team of 52 on-site staff keep the plant in tip top condition and ready to hit full capacity in less than three months • The building is designed with its highest point above seawater at 26 metres, reducing energy costs in li ing water for processing The consTrainTs • The plant is subject to strict water quality controls and has to match the quality of Melbourne's existing water supplies • Plant developers were required to show a high level of sensitivity to the local environment and community The design for the Victorian Desalination Plant is modelled on the first large scale desalina- tion plant built in Australia, in Perth — a Suez design. It has three streams, each capable of operating as a 50 gigalitre plant in its own right, and with the ability for a further half stream to be in operation. The modular approach max- imises efficiency in producing water, particularly for orders be- low full capacity, and by taking account of variables including the cost of power, and seasonal changes in water conditions. "The major design challenges were du- rability, robustness, and certainty of delivery from a plant that had to be flexible enough to cater for different pro- duction modes from Technology and design zero to 150 gigalitres," says Matt Brassington, chief executive of Aquasure. At all stages, redundancy is included to allow scheduled and unscheduled maintenance activities to go ahead without compromising the plant's ability to produce at maximum capac- ity. As a public-private partner- ship, all risks are borne by the contractor, and the technologies and treatment processes were chosen for their low risk profile. "Water quality requirements for this plant are very strict, matching the quality charac- teristics of Melbourne's existing water supplies," says Brassington. The plant uses a full, two-pass reverse osmosis system to remove salt and minerals, resulting in high quality potable water. The entire development, including the desalination plant, covers a 263 hectare site that is landscaped with plants, trees, a dune sys- tem, wetlands, and coastal and swampy woodlands, to reduce the environmental impact of the facility, and its effect on the neighbouring community. A key aspect of the architec- ture of the main plant building, which has a footprint of 38 hectares, is that it is lowered to 26 metres above seawater at its highest point, cutting the amount of energy needed to li" seawater for processing, and reducing the plant's visual impact by integrating it into the landscape. The overall site's design is based on the concept of a "green line" running through the middle, and the plant boasts Australia's largest living roof covered with plants and low shrubs. The roof helps to im- prove corrosion resistance and temperature control at the plant, as well as reducing maintenance costs and noise pollution. Water storage ponds of 1,000 m3 cap- ture runoff from the living roof for irrigation. Of the nine sites that were visited in a feasibility study con- ducted before a site was finally chosen, four locations were shortlisted: the Surf Coast, Port Phillip Bay, Western Port, and Bass Coast. AquaSure's Victorian Desalination Plant fulfils its first water order • The first water order for 50 gigalitres re- ceived 1 April 2016 • The Watersure team ramped up produc- tion in the three months to July 2016 • Plant's modular design allows for flex- ibility in production from zero to 150 gigalitres The Victorian Desalination Project (VDP) is a mega-size seawater RO facility, able to produce up to 150 billion litres of water a year when running at full capacity. Located at the southerly most tip of Australia on the Bass Coast, it was pro- cured by the Victorian State government from AquaSure, a joint venture of Degrémont, Macquarie Capital, and Thiess (now Ventia), in 2009, for a capital cost of $3.5 billion. At the time of buying, a Labour government was in power, and the state was in the grip of a searing drought. However, by the time the project was complete, a mere 37 months later in 2012, rains were plentiful, reservoirs 80 per cent full, and the public had rapidly fallen out of love with the project. When a new coalition Liberal-National government was voted into office in 2013, VDP became a political football and was criti- cised as an expensive white elephant. This year a Labour govern- ment was re-elected, and in April placed an order for 50 billion litres of water in 2016- 17. The decision is backed up by advice from Melbourne's four metropolitan water busi- nesses; as well as analysis of future security of supply, and forecast storage conditions, Bureau of Meteorology out- looks, and customer impacts. The plant is now producing water that is being supplied into Melbourne's water sys- tem, until the current order comes to an end in June 2017. looK Plant operates in three distinct streams, with redundancy built in.