December 2008

Basil and tomatoes help manage dam water

Basil and tomato plants are the offshoots of a new quality improvement project at Kestrel Mine designed to help purify its raw water.

Environmental advisor Ben Anderson said the plants, grown on Kestrel Mine’s 40 megalitre primary raw water dam in a system of floating gardens called aquaponics, help keep unwanted bacteria at bay.

“Cyanobacteria, commonly known as blue green algae, grow in the dam and must be monitored to keep it at safe levels as some cyanobacteria produce toxins that are harmful to humans,” Ben said.

“The basil and tomato plants in the aquaponic system very effectively 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.”

Ben said it was important the dam remained free from high levels of cyanobacteria because, after being treated, the water is used for processing, fire fighting and drinking and showering on site.

“Before we trialled this new aquaponic system, we were using a reactive approach to managing the water,” Ben said.

“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 and cost-effective to manage and provides a sustainable and environmentally sound long term solution to managing bacteria levels.

“Not to mention the offshoot of the project – a crop of fresh, organic plants for employees to take home and enjoy.”

Ben collaborated with Kestrel Mine environmental officer Stuart Jenkinson and Rockhampton nursery owner Neil Fisher on the aquaponic project, based on work by Central Queensland University.

The project featured in Brisbane newspaper, The Courier-Mail.