2.7. One-dimensional vertical column test for MB
removal
The bottom of the column was filled with a sand layer (28 g)
on which OSP (2 g, bulk density of 0.9091 g/cm3) was deposited.
In order to maintain separate homogeneous layers, minimal
hand vibration was performed to make a full-packing system
in the column. 320mL of 10, 20, 30, 40, and 50mg/L MB
solution was fed into the top of column. 20mL of eluent that
had filtered through the OSP and sand layers at a flow rate of
0.8–1.0mL/min was collected continuously from the bottom
outlet.