AWWA WQTC69480

Biological treatment of drinking water to remove manganese (Mn) is an attractive option for some communities as it relies on less chemical inputs and the system robustness has been reported to be high. However, mechanistic details that can help operators better understand the limitations of the technology remain poorly documented. Previous studies have focused on bacteria of the genus Leptothrix, identifying them as one of the predominant organisms in Mn oxidizing biofilms. This research took media from inside the biological filters of four Mn biofiltration plants in the province of New Brunswick, Canada. The water was characterized for all four sites and it was found that Mn removal from all plants is virtually 100%. Biofilm was detached from the sand and tested for the presence of Leptothrix using RT-PCR DNA amplification. Results showed that only one plant contained Leptothrix in its filters while three of the four plants tested positive for MOB through plating. These results, along with the bench-scale data, suggest that while the mechanism of oxidation observed is likely biological, Leptothrix is not necessarily the predominant organism carrying out biological oxidation. Includes 8 references, table, figures.