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The University of Southampton

Research project: Aerobic granular sludge- formation mechanism, application and its scaling up

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Traditional activated sludge process is used worldwide, which is the most successful wastewater treatment process. When the world is preparing different kinds of conference, workshops and other activities to celebrate the centenary of the invention of the activated sludge process, can we question ourselves if this conventional process could continue to play a key role for wastewater treatment when we face the challenges of fossil fuel depletion, global warming and more stringent water discharge standard in the 21st contrary?

Aerobic granular sludge, which features a compact physical structure with a big size, is a novel wastewater treatment process. Compared with activated sludge, it consumes less energy, withstands variable organic loading rates and toxic compounds, requires small footprint, separates solid from liquid easily and makes simultaneous carbon and nutrient removal possible. Therefore, aerobic granular sludge has the great potential to be the next generation technology for wastewater treatment. In this project, the main factors stimulating the bacteria aggregation to form granular sludge are investigated and the possible formation mechanism of granular sludge is explored. Based on the fundamental knowledge of bacteria response to the environment and the understanding on their capability for aggregation, the aerobic granular sludge is applied to treat different types of wastewater. The long-term stability of granular sludge and the bottlenecks for scaling up of this technology are further investigated.

Granule image under Scanning Electronic Microscope
Granule image
Shift of microbial community of granular sludge during the formation period and stable state
Microbial population shift
The size distribution of granular sludge on different operational days
The size distribution
Pilot-scale reactor with granular sludge treating real wastewater
Pilot-scale granular sludge reactor

Related research groups

Water and Environmental Engineering Group


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