Abstract
Membrane fouling by soluble microbial products (SMP) remains one of the limitations for widespread applications of membrane bioreactor (MBR) systems. Over the past two decades, the characteristics and behaviors of SMP have attracted much attention, and efforts have been dedicated to clarify their role in membrane fouling in MBRs. However, to date, there are only few reviews directly relating this area, and the objective of previous reviews is to concentrate on SMP and their implications in biological treatment systems and their effluents. This brief review relating only to SMP-caused membrane fouling evaluation at the fractional level (SMP key components, sub-fractions and hydrophilic and hydrophobic fractions) and at the overall level (SMP overall roles, characteristics and factors) is presented, which could greatly help researchers and engineers to better understand SMP actual contribution to membrane fouling and adopt effective measures to avoid SMP-caused fouling in MBRs.