BHP would stop pumping salty waste water from the desal plant into the ocean at Point Lowly if it failed to meet agreed standards, the company has said.
A 200 megalitre a day coastal desalination plant at Point Lowly in the Upper Spencer Gulf remains the preferred supply of water to meet the extra needs of the Olympic Dam expansion.
But the Supplementary Environmental Impact Statement released today makes a fresh commitment to the health of the marine environment, particularly the Australian giant cuttlefish.
BHP argues fast flowing currents will ensure the salty brine waste from the desalination plant is dispersed “at maximum levels”, on the basis of “extensive modelling”.
If it doesn’t work out that way, the company will stop the flow of discharge water.
“If the return water dispersion from the desalination plant did not meet the regulatory levels or monitoring identified unacceptable impacts, BHP Billiton would stop discharging return water until the issue was resolved,” the company said.
“BHP Billiton is reliant on a long-term reliable water supply to expand Olympic Dam to its full potential. It is therefore in BHP Billiton’s interest to ensure the desalination plant can be operated responsibly in relation to the marine environment.”
If the expansion is given the go-ahead in its current form, waste water from the desalination plant will be discharged at sea under pressure through a purpose designed and built diffuser.
The diffuser would be located in the area of highest tidal currents, 800m from the shore.
“The outfall pipe would be built through a tunnelling process, rather than the traditional trenching method,” the company said.
“This would ensure the seabed and the marine environment is protected from any damage during construction and avoids the cuttlefish habitat.”
But the intake pipe would be constructed through a trenching process, because it goes through soft, sandy areas rather than the rocky reef cuttlefish breeding habitat.
