Toast to waste treatment

Sampling water treated by the new plant at Fonterra's wastewater treatment facility at Stirling are (from left) Otago Regional Council chief executive Graeme Martin, Fonterra hub operation manager Alan Bennett and Fonterra South Island environmental manager Ian Goldschmidt. Photo by Rachel Taylor.

Fonterra operations and environmental managers were joined in Stirling yesterday by dignitaries from the Otago Regional Council, Fish and Game NZ, Department of Conservation and the Clutha District Council to celebrate the official opening of the largest membrane biological reactor (MBR) wastewater treatment facility in the world.

The wastewater treatment facility, which cost $12 million and took two years to build, separates water and solid matter from the wastewater that has in the past been pumped into the Clutha River.

Wastewater treatment takes place in three stages.

Solids, fat and protein are removed from the waste in a dissolved air flotation (DAF) unit, then, using an anaerobic process, bacteria digest the organic components in the wastewater.

Finally, any remaining bacteria and solid particles are removed from the water through an ultra-filtration system.

Fonterra is so impressed with the quality of the water post-treatment, dignitaries were handed glasses and invited to sample the finished product.

Otago Regional Council chief executive Graeme Martin said this facility was the pathway to solving New Zealand's wastewater issues.

"Normally, you wouldn't drink wastewater... What this represents... [is] the investment you have made is right. Nobody downstream needs to know what you are discharging."

Fonterra's South Island environmental manager Ian Goldschmidt said the plant, which was installed in November 2008, has processed more than 1 billion litres of wastewater.

He said the treated water resembled tap water, and solid matter left over from the treatment was recycled and used as fertiliser.