The effect of ozone on tannery wastewater biological treatment at demonstrative scale.

This paper reports the results obtained during an investigation aimed at transferring to the demonstrative scale an aerobic granular biomass system (SBBGR--Sequencing Batch Biofilter Granular Reactor) integrated with ozonation for the efficient treatment of tannery wastewater. The results show that the integrated process was able to achieve high removal efficiencies for COD, TSS, TKN, surfactants and colour with residual concentrations much lower than the current discharge limits. Furthermore, the process was characterised by a very low sludge production (i.e., 0.1 kg dry sludge/m(3) of treated wastewater) with interesting repercussions on treatment costs (about 1 euro per m(3) of wastewater).