Desalination plants in Australia, review and facts

Australia is the driest continent on earth and despite this the installed desalination capacity is still around 1% of the total world’s desalination capacity. This paper reviews the main seawater issues considered in every desalination project—the history, the present situation and the future of desalination in Australia, the suitability of applying reverse osmosis (RO) and the project details of two desalination plants (Sydney and Perth). Ocean currents, seawater temperature and salinity are significant indicators in the assessment of the feasibility of desalination as they affect the production costs, the maintenance frequency and the quality of the product water. Seawater reverse osmosis (SWRO) is the only type of desalination technology currently used or proposed for future large-scale desalination plants in Australia. Every capital city except Darwin has considered building at least one desalination plant as a means of providing water security after several years of unprecedented drought that has significantly reduced dam storage levels. Perth was the first major city to use desalinated water for drinking water supply and by early 2009 Sydney will be the second city. Thirteen other large-scale SWRO plants are being planned or proposed at several locations for the purpose of supplying drinking water.

Desalination of seawater in Australia is expanding and becoming a practical technology even though the prices are still dearer than conventional water. This is a result of water scarcity as a result of climatic change and increasing population in urban centres. RO is still the main technology used for the desalination of sea and brackish water and the only technology to be recommended for the new emerging large-scale seawater desalination plants. Further development and improvement in membrane technology coupled with a sharp decrease in the supply of natural water resources in several Australian cities will make seawater desalination in Australia an extremely popular option. Installing a desalination plant is site specific with the following general environmental impact considerations that applies on all projects: (i) Possible threat to local flora and fauna, (ii) Erosion, (iii) Noise and air emissions, (iv) Disturbance of dunes and seafloor ecology and (v) Disturbance to land species and marine life. Installation of SWRO plants in Australia is classified under the development projects category and is assessed according to relevant environmental acts for environmental impacts of construction on the existing habitats and populations. In general, the desalination project is initiated with a concept plan, followed by Minister’s approvals, call for contracts and contract signatures, building and maintaining the plant. A four-stage contract type (design and construct/operate and maintain) was used for the Sydney and Perth desalination plants with a difference in the period of contract (20 years for Sydney and 25 years for Perth respectively). The desalination project costs had a direct influence on the anticipated water cost, which was exhibited in dearer product water prices for the Kurnell desalination plant (Sydney) if compared with Kwinana desalination plant (Perth). Therefore, the site selection (proximity to water supply infrastructure) and the management plan are crucial for producing low-priced desalinated water, as major extra costs are included in pipeline constructions and plant maintenance. Desalination technology applications in Australia will increase in the foreseeable future as climate change is severely reducing the rate of annual precipitations while the population density in the major cities is increasing. Despite high prices for the production of fresh water from desalination compared to conventional water sources, the scarcity of the latter will make the former a necessity if not a must.