To evaluate leaching characteristics and adsorption capacity
of green roof substrate, a packed column arrangement was
used. A glass column (internal diameter ¼ 20 mm and
height ¼ 350 mm) was designed. It should be noted that
average particle size of green roof substrate vary from 0.25 to
10 mm. At the top of column an adjustable plunger was
attached to adjust the bed height. Around 38.6 g of green roof
substrate was packed within the column, yielding bed height
of 25 cm. There was a 3 cm layer of glass beads at the top of the
column to distribute the influent uniformly. The influent (DI
water or spiked DI water) was pumped downwards through
the column using a peristaltic pump at a flow rate of 0.3 L/h.
Column effluent samples were collected at regular time