2025 Volume 23 Issue 1 Pages 36-45
Taste and odor are common problems in water supplies worldwide. While many treatments have been applied, biological drinking water treatment has attracted attention for removing 2-methylisoborneol (MIB). However, the potential mechanism of MIB removal via biological drinking water treatment has not yet been characterized. This study aimed to determine the MIB removal potential of biological active carbon (BAC) using a laboratory-scale one-path column assay system. Sodium azide was used to discriminate between adsorption removal and biodegradation of BAC. Volumetric removal potential of BAC collected from a pilot-scale up-flow biological filter placed before coagulation/sedimentation (BAC-UF, n = 2) showed 5.8–7.2 mg MIB/m3 BAC/h, while that of BAC collected from a full-scale BAC filter placed after ozone oxidation (BAC-OZ, n = 1) was 2.2 mg MIB/m3 BAC/h. Biodegradation accounted for 23% of the volumetric removal rate of BAC-UF, whereas almost 100% of the removal was attributed to adsorption for BAC-OZ. Although the copy numbers of prokaryotic 16S rRNA genes of BAC-UF and BAC-OZ were similar, the 16S rRNA copy numbers of BAC-UF (1.6 × 1011–1.1 × 1012 copies/g dry BAC) were higher than those of BAC-OZ (2.7 × 1010 copies/g dry BAC). The abundance of active microbes may be related to differences in the biological removal potential.
