Dec. 19 (Bloomberg) — Suez Environnement, Europe’s second- biggest water company, said the Victorian desalination plant on the Bass coast near Melbourne had reached its final contractual milestone after more than three years of construction.

Degremont, Suez’s water treatment subsidiary, and Thiess’s venture will now manage operations and maintenance of the Wonthaggi reverse-osmosis plant for 27 years, when it will be handed back to Victoria’s government, said Paris-based Suez, which supplies 30 percent of Australia’s drinking water.

The plant, designed to safeguard Melbourne against water shortages, provides a guaranteed source of drinking water independent of rainfall of as much as 450,000 cubic meters a day, delivering it by pipeline to Cardinia reservoir, the AquaSure venture said. Construction delays and cost overruns from strikes and bad weather caused Suez to take 322 million euros ($428 million) of provisions on the project.

Passage of the reliability testing finalization phase completes one of the biggest reverse-osmosis plants to convert seawater into potable water, according to Suez and Australia’s largest builder, Leighton Holdings Ltd. Construction on the public-private partnership project began in September 2009.

The project was composed of four interconnected parts — the desalination plant, seawater inlet and outlet tunnels, water transfer pipeline and underground power supply — and includes energy-recovery devices to reduce power consumption.

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