An environmental engineer has developed and enacted plans for a single site which could process human waste and harvest oil and gas without harmful emissions.

Associate Professor Tryg Lundquist from California State Polytechnic University may be the one to usher-in the future of wastewater treatment, with a complex maze of ponds through which green algal slurry flows.

Within the maze, the alga is used to treat wastewater while giving off useful biofuels as a by-product.

“You can use less electricity, you can recycle the water, the nitrogen and the phosphorus, you can keep mixing the algae into a fuel, and it keeps rolling on in an endless cycle,” Lundquist says.

The key to the system is the layout itself.

It uses a series of channels dubbed ‘raceways’ to push the fluids through a loop of shallow ponds. Waterwheels gently keep the mixture stirring around, and the increased movement and exposure to sunlight maximised the growth of waste-eating algae.

Neither algae-based wastewater treatment nor deriving biofuel from the simple organic matter is a new idea. Combining the two processes however, is. The hybrid sites might be the key to bringing the price of biofuel low enough to compete with traditional substances.

Dr David Batten, an industrial ecologist with The Temaplan Group and formerly with CSIRO's Energy Flagship says algal oil is on the verge of full industrial uptake, estimating that enough algal fuel could be produced from wastewater to replace up to 10 per cent of Australia's current diesel use.

“It would be good for the wastewater companies to start weaning themselves off the more costly mechanical methods and start thinking about algae as a solution,” he said.

“The downside of it is the land usage. You need a lot of land for a solar based system like algae,” Lundquist says.

But still more than worth the effort, as he sees it; “some technology efforts don't have any immediate pay-offs, but with algae we can be getting little pay-offs as we go.”