Algae-bacteria clumps could clean sewage without power-hungry aeration
Wang G, Liu Z, Ji K, Wang M, Xie X
Phytoremediation
The pond scum you'd normally skim off a rain barrel turns out to be part of a self-organizing team that could make water treatment plants near your town cheaper to run and lighter on carbon emissions.
Researchers looked at tiny round clusters made of algae and bacteria living together, where the algae on the outside soak up sunlight and pump out oxygen, and the bacteria buried inside use that oxygen to digest waste. Because the clump makes its own oxygen, treatment plants wouldn't need to run energy-hungry air pumps, which is normally one of the biggest costs of cleaning water. The review looks at how these clumps form and stick together, what conditions help them grow best, and how well they filter out both common pollutants and newer contaminants like pharmaceuticals.
Key Findings
Photogranules self-assemble with a photosynthetic outer layer (mainly microalgae and cyanobacteria) surrounding a heterotrophic bacterial core, enabling aeration-free operation via in-situ oxygen production
Formation depends on initial microbial attachment, light-driven stratification, and metabolic cross-feeding between the photosynthetic and heterotrophic layers
Operational factors like hydrodynamic shear, light regime, and reactor design critically affect granule stability and pollutant removal, including emerging contaminants
chevron_right Technical Summary
Scientists are reviewing how ball-shaped clumps of algae and bacteria, called oxygenic photogranules, can clean wastewater without the energy-hungry aeration pumps that treatment plants rely on today. The algae on the outside produce oxygen that bacteria in the core use to break down pollutants, offering a cheaper, more sustainable way to treat sewage.
Abstract Preview
Original paper
Oxygenic photogranules in wastewater treatment: Formation mechanisms, engineering optimization and prospects.
Oxygenic photogranules (OPG) are a novel class of biogenic aggregates that orchestrate a synergistic division of labor within a single microstructure. Characterized by a photosynthetic outer layer ...
open_in_new Read full abstractAbstract copyright held by the original publisher.
Was this useful?
Want to tell us more? (optional)
Thanks for the note!
Something went wrong — please try again.
Too many submissions. Try again in an hour.
Street trees cut heat deaths by 39 percent in European cities
Trees in your local park or street aren't just pretty — they are literally keeping people alive during heatwaves, and planting even a modest number of the ri...
Urban ecology is the scientific study of living organisms and their interactions within densely developed environments dominated by buildings, paved surfaces, and human infrastructure. For plant science, this field is essential because it investigates how plants adapt and survive in fragmented
arrow_forward Explore topic