The aim of this study was to demonstrate the complementarity of combining membrane bioreactor
(MBR) treatment with UV oxidation or high pressure membrane filtration processes such as nanofiltration
(NF) or reverse osmosis (RO) for the removal of trace organic contaminants (TrOC). The results
suggest that the removal mechanisms of TrOC by either UV oxidation or NF/RO membrane filtration differ
significantly from those of an MBR system. Thus, they can complement MBR treatment very well to
significantly improve the removal of TrOC. MBR treatment can effectively remove hydrophobic and
readily biodegradable hydrophilic TrOC. The remaining hydrophilic and biologically persistent TrOC were
shown to be effectively removed by either UV oxidation or NF/RO membrane filtration. The combination
of MBR with UV oxidation or NF/RO membrane filtration resulted in a removal ranging from 85% to
complete removal (or removal to below the analytical detection limit) of all 22 TrOC selected in this
study. In particular, it is noteworthy that although MBR treatment and direct UV oxidation separately
achieved low removal of carbamazepine (a widely reported problematic compound), the combination of
these two processes resulted in more than 96% removal.