New Zealand company Aquaflow, which I wrote about in this post, has received praise in an article in Yale Environment 360 describing a project to use the city of Minneapolis’s sewage as a feedstock for algae from which biofuel can be derived. A University of Minnesota professor, Roger Ruan, is engaged in the research and speaks optimistically of its prospects. Early in the article comes this acknowledgement:
“Growing fuel-producing algae in waste is not Ruan’s idea alone. The concept drew international attention in 2006 when a startup in New Zealand called Aquaflow successfully harvested biofuel from open-air ponds at wastewater treatment plants. The company expects to be able to produce the biofuel on a large scale, and recently attracted the attention of major players in the airline industry by announcing it had distilled a special blend that meets the technical specifications for jet fuel.
Aquaflow’s advances, combined with the Pentagon’s interest in biofuels as an alternative to conventional jetfuels, has sparked a flurry of academic and industrial research in the United States.”
Not bad for a small New Zealand operation, and an encouraging sign of how technologies can move rapidly from small beginings to be widely adopted on scales which hold real promise for for a decarbonised future.
The Minneapolis project is not identical with Blenheim’s. But it has in common the use of nutrient-rich sewage as feedstock for the algae and the side benefit of clean wastewater. Ruan does not rely on wild algae naturally occurring in open ponds as Aquaflow does, but has selected algae from the wild which have proved particularly suited to his operation. Nor does he work with open ponds, explaining that they pose difficulties in winter in northern climates. Instead the algae are confined to indoor bioreactors well exposed to artificial and natural light and the sewage is passed through the reactors. The 30% yield of oil is higher than Aquaflow’s 5-10%, but the process is much more complex and capital intensive. Aquaflow opted for its much simpler operation deliberately, judging the lower yield was offset by the lower costs. There will no doubt be many different approaches developed in different places, and some will prove more effective than others, but Aquaflow has clearly earned credit for its pioneering work.