Algae Offers Hope For Energy-Positive Wastewater Treatment

Deep in the Sulphur springs of Yellowstone National Park there thrives a resilient type of algae that may be the key to energy-positive wastewater treatment.

Peter Lammers, an Arizona State University bioenergy professor, is leading a team of researchers who are attempting to clean wastewater with Galdieria sulphuraria, a microorganism that intrigues scientists for its resiliency in unhospitable conditions, ability to break down organic molecules, and photosynthesize like a plant.

“Because of the way it works wonders at Yellowstone, Lammers and a team of researchers are wondering whether the microorganism can be leveraged to do something else: turn wastewater clean. To test the hypothesis, he and his colleagues are diverting wastewater from the city of Las Cruces, New Mexico’s sewer system and redirecting it into bags that are lined with Galdieria sulphuraria,” according to TriplePundit, a sustainability news source.

The scientists are testing their hypothesis that the microorganisms will be an effective agent for nutrient removal and the initial results have been encouraging.

“At the Las Cruces pilot project, the algae use sunlight and carbon dioxide to grow, breaking down over 95% of the nitrogen and phosphates in a couple of days. The high temperatures and acid conditions are also tough on bacteria, viruses and parasites. Sewage treated like this should require 10 times less chemical disinfectant than usual,” The Guardian reported.

The researchers are intrigued by this system’s potential to save hugely on energy consumption.

Based on preliminary results, Lammers and his team believe that Galdieria sulphuraria could eliminate a wastewater treatment plant’s electricity costs, which may account for up to 60 percent of operating costs.

The Las Cruces tests are going so well that a similar project is scheduled to start in Phoenix, AZ, by next month. But there may be challenges if the researchers ever hope to take this method to the next level.

“Scaling up to a city-size project presents tough engineering challenges, including handling the acidic wastewater, mixing the solution efficiently, recycling millions of plastic bags and collecting the algae for conversion into biofuel,” The Guardian reported. “Space is likely to be another issue. Lammers calculates that a farm big enough to handle the sewage of a million people would need around 15,000 acres of plastic bags, as well as plenty of sunlight to keep the photosynthesis ticking along.”