Friendly Bacteria at Center Stage: Treating Wastewater with Less Energy, Lower Emissions

More than half of the energy required for wastewater treatment is used to supply oxygen to the biological reactor. The bacteria need oxygen to function. However, treatment plant operators do not know exactly where in the basin the oxygen is needed. That’s why they have to add more oxygen to the water than the bacteria actually need. "At the moment, only 20% of the oxygen ends up in the bacteria, while the remaining 80% goes to waste," says Anna Mikola, professor of practice for municipal wastewater treatment at Aalto University in Helsinki, Finland. She is leading a project that has just begun