Water management a major future challenge

Western Australia’s growing population, driven to a large degree by the resources boom, has placed increasing importance on the management of the state’s water supplies.

To help meet that demand, the government has backed construction of a second desalination plant to deliver an extra 100 gigalitres of drinking water each year.

An ongoing drought in the south of the state has prompted the government to invest an estimated total of $955 million to the Southern Seawater Desalination Plant, located near Binningup in the Shire of Harvey.

The plant will rival the 45GL Perth Seawater Desalination plant in Kwinana, which has been operating since 2006, by producing around 50GL per year into the Integrated Water Supply Scheme, with the potential to increase to 100GL.

Last month, the Water Corporation announced two Spanish consortiums, Acciona Agua Australia Pty Ltd along with United Utilities Australia Pty Ltd and Technicas Reunidas SA with Valoriza Agua, had been shortlisted to design, build, operate and maintain the plant for the next two years.

The consortia will battle it out over the next few months before a final decision is made.

The Water Corporation hopes to announce shortly the next steps of the tendering process for the supply of 200 gigawatt hours per year of renewable energy for the desalination plant.

Construction work on the Binningup plant is expected to start next year and is scheduled to be operation in 2011.

Meanwhile, the Beenyup Wastewater Treatment Plant Amplification project in Perth’s northern suburbs will increase its daily solids treatment capacity by 15 megalitres to 135ML.

An alliance between the Water Corporation, Black & Veatch, Thiess and Sinclair Knight Merz was formed in late 2006 with the aim of upgrading existing wastewater treatment plants that include Beenyup, Subiaco and Woodman Point.

The last of these, while increasing its daily solids treatment capacity to 160ML, will also have its odour levels cut by 50 per cent and that target is expected to be reached by the end of this year.

The alliance announced that construction has started on the new odour control facility, a key component of the stage one odour control upgrade.

A prominent feature of the facility will be the 50-metre high stack, which caters for the dispersion of treated air extracted from the most odorous areas of the plant.

The existing stack is currently 25 metres high.

Currently, the Woodman Point wastewater treatment plant services more than half a million people in the southern metropolitan area, and together with Beenyup and Subiaco, treats around 80 per cent of the state’s wastewater.

In all, $411 million will be invested into the Alkimos Wastewater Scheme to service the growing northern suburbs population, which is predicted to reach 150,000 by 2030.

The project will service the northwest corridor and site and land clearing is likely to start within the next couple of months.

December 2010 has been pegged as the likely finish date for the scheme.

Connecting to Alkimos is the $89.5 million Quinns Main Sewer, where the sewer will be extended by five kilometres over the next two years under an alliance that includes Multiplex Engineering, Macmahon Contractors and Zueblin Australia.