Biological Manganese oxidation in Biological Oxygen-dosed Activated Carbon (BODAC) Filters

The previous two-year monitoring of Biological Oxygen-dosed Activated Carbon (BODAC) filters' performance revealed that complete manganese (Mn) removal consistently occurred in the filters, mostly in BODAC 1. The removed Mn seemed to be temporarily retained on the BODAC granules' surface and washed out of the filters simultaneously with part of the biofilms during the backwashing procedure. Analysis of BODAC granules' microbial community composition showed that (putative) nitrifiers and Mn-oxidizers dominated the resident core microbiomes of BODAC granules. Still, other molecular biology techniques, including qPCR and proteomics, failed to confirm the role of (putative) Mn-oxidizers for Mn removal in BODAC filters. In this study, we carried out enrichment experiments to prove that biological Mn-oxidation took place in BODAC filters.