Schematic drawing of coupled photo- Fenton-biological flow reactor.
Fixed bed bioreactor: column containing biolite colonised by activated sludge and having 1 L of water capacity. The effluent deriving from the photochemical stage was circulated from flask 2 by the pump 5 through the bottom of the column. pH was adjusted at 7.0 in flask 3 where the nutrients (N, P, K and oligoelements) for the bacterial activity were also added. O2 concentration was controlled by an O2 probe at the top of the column.