An integrated biological and AOPs processes treatment would provide a viable alternative and
could help remove hardly biodegradable recalcitrant organic matter (ROM) from the effluent
economically and effectively. Effluents streams containing toxic and inhibitory compounds can be
treated by AOPs to produce biodegradable intermediates, which are then readily treated biologically.
Beltran et al. [22] applied the combined treatment (ozonation coupled with activated sludge) to a
diluted sherry stillage, a high strength wastewater. The two ways of coupling ozonation with activated
sludge are proposed by authors. Ozonation prior to activated sludge is advised for high-concentration
wastewater to reduce polyphenol concentration, thus removing inhibiting effects. For wastewater with
low polyphenol concentration the activated sludge-ozonation-activated sludge sequence is preferred to
enhance the overall process performance in terms of oxidation efficiency and sludge settling. Chang et
al.