Environment

BSL aims to achieve environmental best practice by minimising waste, emissions and impacts associated with our activities through implementing effective mitigation and management strategies.
 

Air emissions

Emissions of fluoride and particulates produced from the aluminium smelting process are captured in a network of ducts and sent to Gas Treatment Centres (GTC) for processing.  BSL uses the dry scrubbing technology to clean the gases collected from the smelting process, with alumina as the scrubbing agent.  All fluorides and particulates captured from the GTCs are recycled back into the smelting process.

Dry scrubbing is more than 99% efficient at removing these impurities from the gases collected.  BSL operates six GTC units for the Reduction Lines, and a further two units for the anode baking furnaces.

Air emissions are measured monthly to ensure that BSL operates within its licence limit.

Landfill

During its operating life, BSL has had eight on-site landfills. BSL has an ongoing focus on re-using, reducing and recycling materials on-site. Timber is either re-used or chipped for use in gardens, erosion control or sale off-site. On-site active recycling programs are in place for tyres, fluorescent tubes, plastics, spent anodes, batteries, cardboard and paper, oils, and printer cartridges. Only around 550 tonnes of general waste leaves site each year – the same amount that around 550 individual people would produce annually.


Spent Cell Lining (SCL)

Spent Cell Lining (SCL) is a by-product of the smelting process and BSL is leading the way in finding an alternative use. A joint venture between BSL and Cement Australia sees approximately 10,000 tonnes per annum of SCL processed into calcined ash on-site. Cement Australia uses this product as a fuel source for their kilns.


Spent carbon anodes

BSL currently recycles spent carbon anodes after they have been consumed in the Reduction Line cells. This involves removing the spent carbon anodes from the cell and leaving them to cool for 24 hours. They are then crushed for re-use in the carbon plant. New anodes contain approximately 30% recycled material.


Refractory bricks

Refractory bricks are commonly used to line the various furnaces in the Carbon plant and in Metal Prouducts. Previously used refractory bricks were crushed analysed and approved for use in the base of the new Carbon Bake Furnace 4 (CBF4), commissioned in 2012.
 

Settling ponds

A series of five drains on site capture all process and storm water, and takes the water to settling ponds so only clean water is discharged from the site. BSL has two settling ponds which catch all water originating from site. Water is retained in the settling ponds until it can be processed through a reed bed to remove large portions of the sediment load.

Frequent water quality testing is conducted to confirm BSL is operating in accordance with its licence limits.
 

Energy efficiency

The majority of power for use at BSL is purchased through the Gladstone Power Station. BSL owns and maintains in excess of $500 million of power supply equipment, which includes 275,000 volt substations. Power consumption on site is approximately 900 megawatts of electricity.

BSL is continuously looking at ways to operate the plant more efficiently to result in reducing the power required to operate the plant.

BSL had implemented a number of projects to do this, regarding lowering voltages in its Reduction Lines area, creating low energy designs of Reduction Line cells.

In 2013 BSL commissioned the Compensating Loop project, a major capital improvement project costing over $16.5 million, which greatly reduced power consumption and improved efficiency within the Reduction Lines.