Tomato plants help mine control blue-green algae

Kestrel Mine is using basil and tomato plants to control levels of blue-green algae in its dam water as part of an innovative quality improvement project.

Kestrel Mine environmental advisor Ben Anderson said the plants are grown on the mine's primary raw water dam in a system of floating gardens called Aquaponic units.

"Cyanobacteria, commonly known as blue-green algae, grow in the dam and must be monitored to keep them at safe levels, as some cyanobacteria produce toxins that are harmful to humans," Mr Anderson said.

"The basil and tomato plants in the aquaponic system compete for the same trace elements to grow as the bacteria, so by growing the plants, we're denying the bacteria the nutrients they need to thrive."

Mr Anderson said it was important the dam remained free from high levels of bacteria.

"The dam water is piped to the mine from an offsite source and after being treated, is used for coal processing, fire fighting, drinking and showering," Mr Anderson said.

"Before we trialled this new aquaponic system, we were using a reactive approach to managing the water.

"We would have to wait until water tests showed elevated levels of bacteria before treating the water with chemicals, which was a costly and time consuming process.

"The new system is proactive, relatively simple, cost-effective and provides a sustainable, environmentally sound long term solution to managing bacteria levels.

"There's also the added bonus of producing organic plants that are perfectly safe to eat for our employees to take home and plant in their gardens."

The idea of using aquaponic units to control cyanobacteria was pioneered by researchers at CQUniversity, Associate Professor Larelle Fabbro, Les Unwin and Leonie Barnett, in collaboration with Australian Coal Association Research Program.

"We were looking for a simple and safe way to remove nutrients from the water to prevent bacteria from growing," Associate Professor Fabbro said.

"Our research showed tomato, basil and silverbeet plants are particularly effective at removing compounds from the water, including phosphorus and molybdenum which are required for the growth of blue-green algae.

"The units can be pulled out if ever any adverse effects occur, and can be cleaned at the end of each season, making them ideal for use in industry."

Kestrel Mine general manager operations Tony Lennox said the aquaponics trial was part of a quality improvement project.

"At Kestrel Mine we're constantly looking for new and innovative ways of working," Mr Lennox said.

"When our employees hear about simple, effective methods that achieve results, we encourage them to get on board and try them out.

"The aquaponics project is a great example of this, and reinforces the strength of working with other institutions, such as CQUniversity and ACARP to achieve sustainable environmental benefits."

Media release_Tomato plants help mine control blue-green algae [PDF: 19 KB]