Accumulation of manganese oxides in biological activated carbon filters: Implications for biodegradation studies

Abstract A comparison of granular and biological activated carbon (GAC BAC) media used for drinking water treatment was made to assess differences in surface elemental composition. Fresh GAC, recently commissioned GAC end‐of‐service life BAC from a plant New Zealand were analyzed using scanning electron microscopy, energy‐dispersive spectroscopy, inductively coupled plasma‐mass spectrometry (ICP‐MS). Imaging revealed dense microbial colonization the compared media, mineralized layer high manganese oxygen. ICP‐MS analysis also confirmed levels Mn relative media. As many bacterial species known colonize filters are as oxidizers, this suggests biogenic origin Mn‐oxide deposition on surface. Given properties Mn‐oxides, they may be implicated mechanism by which bacteria capture metabolize substrates filters.