Flocculation took place at 60 s−1 mean velocity gradient for
20 min. Tap water was pressurized at 450 kPa for 15 min. In a typical
run, the columns with flocculated SBR-effluent were filled with air-
Table 1 saturated water fed from the saturation chamber. The recycle rate was modified according to the volume changes in both the flocculated
SBR-effluent and the air-saturated water.