The lab-scale SBBGR, fully automated and controlled by
a programmable logic controller (PLC), was made up of a 1 m
plexiglass cylinder with internal diameter of 0.19 m (Fig. 1a). Two
clearly distinct parts can be distinguished in the reactor: the
microbial bed (volume: 14 l), situated at the bottom, represents
the active part and develops on a plastic support material (KMTk1
elements from Kaldnes, Norway) kept between two sieves,
while the top part of the reactor, the liquid phase, houses two
aerators (each with a flow of 150 Nl h1).