Technology:

Using Bacteria to Eliminate Geothermal Waste (Stuff.co.nz)

Contact Energy's new facility near 

Taupo. (Courtesy Waikato Times)

Bacteria that dine out on toxic waste are being used to consume hydrogen sulphide from the Wairakei geothermal power station in a unique environmental project.

Since the power plant was built in the late 1950s it has drawn water from the Waikato River to be used as a coolant before pumping the water back into the river. The only catch was it picked up hydrogen sulphide from the geothermal steam.

Studies show that hydrogen sulphide damaged the aquatic environment and it was likely the Wairakei discharge was having an impact on the Waikato River ecosystem and nearby lakes.

The Waikato Regional Council indicated in the early 2000s that the situation would soon change and the new consent conditions kicked in this August.

The bioreactor uses sulphur oxidising bacteria, that grow naturally in the river, to remove the contaminant from the power station's cooling water as it flows through five banks of piping.

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