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Kiwi environmental innovation receives international honours
Beca has been awarded Global Winner for the Design Projects Category of the 2014 International Water Association (IWA) Global Project Innovation Awards Competition. The design work on Contact Energy’s Wairākei bioreactor is a Kiwi innovation and the only New Zealand winner announced at the internationally recognised 2014 IWA Global Project Innovation Awards in Portugal. Jointly developed by Beca and Contact, the bioreactor is a unique, world-first solution to improve the quality of water that is discharged from the iconic Wairākei geothermal power station into the Waikato River.
"To work with Contact Energy from the beginning, developing and testing innovative concepts through to the design and construction of the Wairākei bioreactor has been immensely rewarding for the Beca team", says Beca CEO, Greg Lowe. "This is another great example of New Zealand talent delivering world class project outcomes."
"I’m immensely proud of our bioreactor," says Contact Energy CEO, Dennis Barnes. "As a world-first it’s great to see this example of Kiwi ingenuity recognised at an international level."
The Wairākei bioreactor was developed to reduce hydrogen sulphide (H2S) discharges from the Wairākei geothermal power station to the Waikato River. This was identified through a 10-year programme of environmental and technical studies which examined the environmental impacts from the on-going operation of the power station. These studies showed that H2S levels in the Waikato River downstream from the Wairākei power station were impacting the water quality.
The bioreactor was developed as a treatment facility for the reduction of H2S in the cooling water by harnessing the power of billions of naturally occurring sulphide oxidising bacteria endemic to the Waikato River.
In creating this solution Beca engineers used several innovative engineering techniques, including:
- A tubular biofilm reactor designed around a large network of almost 400 kilometres of pipes that create an environment for the bacteria to live and grow
- Excavated soil and pumice from the site was mixed with concrete to hold the 1900 parallel polythene pipes in place, saving considerable costs and
- A syphon configuration for the bioreactor hydraulic design lowers the pumping head to minimise power usage and also contributes to significant cost savings.
To date, the bioreactor is reducing H2S in the cooling water discharges by almost 8,000 kilograms per week. It is also on track to achieving the August 2016 milestone of an overall reduction of 95 per cent.
The IWA Global Project Innovation Awards is a prestigious global competition which recognises and celebrates innovation and excellence in water engineering projects around the world.
The Wairākei bioreactor was recently given the accolade Gold Award of Excellence at the ACENZ (Association of Consulting Engineers) 2014 INNOVATE NZ Awards and entered for the IChemE Awards 2014 in recognition of chemical engineering innovation and excellence. Last year it was also awarded the ‘Energy Project of the Year’ and ‘Environmental Excellence’ awards at the 2013 Deloitte Energy Excellence Awards (NZ) and received the 2013 New Zealand Engineering Excellence Award in the Chemical, Bio and Food category.
