The Department of Environment and Conservation in 2003 ordered Orica to stop the spread of a plume of chlorinated hydrocarbon contaminated groundwater at Botany, which was advancing approximately 100 metres a year toward Botany Bay.
NSW Environment Minister Bob Debus on Friday announced the completion of the plant ahead of the October 31 deadline to clean up what he called "one of the worst incidents of pollution in the southern hemisphere".
The plant is designed to extract and treat up to 15 million litres of polluted groundwater a day.
"There are all sorts of very unpleasant chemicals within the groundwater plume and the last thing we would want to see is it beginning to pollute the bay itself," Debus said.
Asked whether the plant would definitely prevent the contaminated water reaching the Bay, however, Debus said: "I don't believe anyone's in a position to give total guarantees."
"But there can be no doubt that the installation of these three lines of powerful pumps is drawing off the polluting groundwater and allowing it to be retreated in the plant," he said.
As an extra safeguard, an independent monitoring committee has been established to oversee the plant's performance.
Source: AAP NewsWire