Fouling with aerobic granule membrane bioreactor

Area of Science:

• Environmental biotechnology
• Wastewater treatment
• Membrane processes

Background:

• Aerobic granulation (AG) and membrane bioreactor (MBR) are advanced biological wastewater treatment technologies.
• Membrane fouling is a critical challenge affecting the performance and longevity of MBR systems.

Purpose of the Study:

• To investigate and compare membrane fouling in a combined aerobic granular membrane bioreactor (AGMBR) and a conventional MBR.
• To identify the causes of irreversible membrane fouling in both processes.

Main Methods:

• Utilized multiple staining and confocal laser scanning microscopy to observe irreversible fouling on hollow-fibre membranes.
• Assessed fouling after physical and chemical washing to differentiate between external and internal fouling layers.

Main Results:

• Both AGMBR and MBR experienced irreversible fouling primarily due to internal biofilm formation.
• AGMBR demonstrated reduced cell penetration and internal fouling compared to MBR.
• Internal biofilms in both systems consisted of live cells within a protein and polysaccharide matrix, with AGMBR biofilms being denser and thicker.

Conclusions:

• Internal biofilm development is the principal cause of irreversible fouling in both AGMBR and MBR membranes.
• The AGMBR process shows potential in mitigating internal membrane fouling by retaining granular biomass.
• Strategies to prevent internal biofilm formation are crucial for enhancing the operational efficiency and lifespan of membrane bioreactors.