The recirculation pathway conditions were as follows and the samples
were denoted as band S1, sampling port 1 at Run 3; band S2,
sampling port 1 at Run 4; band S3: sampling port 2 at Run 4; band
S4, sampling port 3 at Run 4 and S5: sampling port 1 at Run 6. The
dominant species observed was Clostridium pasteurianum at bands
S1 to S4. However, band S5 was not dominated by this species and
this is supported by the lower system performance.