Characterization of cake layer in submerged membrane bioreactor

Area of Science:

• Environmental Science
• Biotechnology
• Materials Science

Background:

• Cake layer formation on membranes is a significant operational challenge in membrane bioreactors (MBRs).
• Understanding the composition and formation mechanism of this cake layer is crucial for optimizing MBR performance in wastewater treatment.

Purpose of the Study:

• To investigate the cake layer formation mechanism in a membrane bioreactor used for synthetic wastewater treatment.
• To identify the major organic and inorganic components contributing to membrane fouling.

Main Methods:

• Particle size analysis (PSA)
• Scanning electron microscopy (SEM)
• Confocal laser scanning microscopy (CLSM)
• X-ray fluorescence (XRF)
• Energy-dispersive X-ray analysis (EDX)
• Fourier transform infrared (FTIR) spectroscopy

Main Results:

• Small particles in sludge suspension exhibit a strong tendency to deposit on the membrane surface.
• Bacterial clusters and polysaccharides are identified as major contributors to membrane fouling via SEM and CLSM.
• FTIR analysis confirms proteins and polysaccharides as key biopolymer components.
• EDX and XRF analyses reveal Mg, Al, Ca, Si, and Fe as the predominant inorganic elements in the fouling cake.
• Bridging between biopolymers and inorganic compounds enhances fouling layer compactness.

Conclusions:

• Effective control of biopolymers and inorganic elements within the bioreactor is essential for minimizing membrane fouling.
• The findings provide insights into mitigating operational challenges in MBR systems.