Effects of biofilm formation on membrane performance in submerged membrane bioreactors

Abstract

The effects of biofilm formation on membrane performance were evaluated for a submerged membrane bioreactor (sMBR) system with six different types of micro- and ultrafiltration membranes (working volume=19 l). After operation for 24 h the permeability of the membranes with a larger pore size (microfiltration) decreased to that of the membranes with a much smaller pore size (ultrafiltration). Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) confirmed that biofilms could reduce the influence of the membrane surface properties. The chemical oxygen demand (COD) removal efficiency was 95% for the oily wastewater treatment in the sMBR where the filtration process made an important contribution (47% based on feed COD). Significant enhancement in COD removal occurred at the initial filtration stage because of biofilm formation and the dynamic member role of the biofilm layer. Membranes with various pore sizes had approximately the same permeate quality that was attributed to the biofilm on the membrane surfaces. Nevertheless, the ultrafiltration membranes had 43% more COD removal efficiency than the other applied membranes at the beginning of filtration (before biofilm formation) because of the smaller pore sizes and better sieving.

Experimental Study and Modeling of Fouling in Immersed Membrane Bioreactor Operating in Constant Pressure Filtration

“…Furthermore, the cake layer acted as a second biological barrier in removing COD. This is in agreement with previous reports which showed that the cake layer can affect COD removal in the iMBR [35]. Figure 2 illustrates application of Hermia's model (2) to different experimental conditions.…”

Multivariate Chemometric Analysis of Membrane Fouling Patterns in Biofilm Ceramic Membrane Bioreactor

“…Mixed liquor suspended solids (MLSS), chemical oxygen demand (COD) and sludge relative hydrophobicity (RH) are among the main characteristic parameters of activated sludge suspension that are traditionally monitored in an MBR system [22,[26][27][28][29][30][31].…”

Application of wastewater treatment in sustainable design of green built environments: A review

“…Concentration polarization, external fouling, and internal fouling [120][121][122] Biofouling, organic fouling, and inorganic fouling [123] Reversible, irreversible, residual, and irrecoverable fouling [124] Types Concentration polarization [125,126] Biofouling (biosolids) [131,132] Reversible fouling [136] Irreversible fouling [137] External fouling [127,128] Organic fouling [133,134] Residual fouling [138] Internal fouling [129,130] Inorganic fouling [135] Irrecoverable fouling [139] sheets as the second stage. They discovered that the fouling and flux decline in hybrid membrane methods are influenced directly by the membrane surface characterization.…”