*3.1. Full-Scale Filter Test*

### 3.1.1. Initial Intermittent Operation Stage

The results are shown in Figure 3. The filters had a certain manganese removal capacity due to the inoculation at the initial stage of operation, and the manganese removal rate was about 50%; there were some differences between these 6 filters due to the initial difference of the filters and the difference of operation which could not be completely the same, but the trend was similar. After five months of operation, the manganese concentration in the effluent of the filter did not show a downward trend with time, it just fluctuated up and down, indicating that the number of ferromanganese oxidizing bacteria in the filter has not been proliferated and the activity was in an unstable stage [23].

**Figure 3.** Mn in the influent and effluent (during the stage of intermittent operation; samples are taken once every three days of operation).
