2022 Volume 45 Issue 4 Pages 159-169
The objective of this study was to deepen the understanding on the behavior of biopolymers in the integrated membrane system (IMS) for the reclamation of municipal wastewater effluent, with the final goal of obtaining insights for better fouling control of the reverse osmosis (RO) membrane. Experimental data showed that alginate-like polysaccharide (ALP) is a major kind of biopolymer and accounts for 48–64% in secondary wastewater effluent (SWE) . However, although it is well-known that alginate forms multimers larger than 0.1 μm in the presence of calcium ions (Ca2+) , experimental data showed that biopolymers in SWE were not removed by a virgin 0.1 μm microfiltration (MF) membrane. This result could be explained by the block fractions of ALP in SWE. Specifically, it was found that the majority (～70%) of ALP in SWE was categorized in the MM block, which has lower affinity to Ca2+ than GG or MG blocks, and that the percentage of GG block, which has the highest affinity to Ca2+ than other types of blocks, was only 5.1–6.3%. Nonetheless, up to 62% of biopolymer, mainly polysaccharide, was removed by a fouled MF membrane.
