Dyeing and finishing wastewater treatment by Sequencing Batch Biofilter Granular Reactor

This paper reports the results obtained using the sequencing batch biofilter granular reactor (SBBGR) for the treatment of the wastewater from a dyeing and finishing factory. SBBGR is a new innovative technology for biological wastewater treatment which possesses various promising features for textile wastewater treatment at each factory. Wastewater originating from dyeing textile factories is hard to depurate as it is usually characterised by considerable amounts of different pollutants, which are often recalcitrant, toxic and inhibitory. The results have shown that even at an organic load value as high as 2.4-2.6 kgCOD/m3.d SBBGR gives treatment efficiencies which allow the discharge into municipal sewer system. Furthermore, SBBGR was characterized by a sludge production as low as 0.1 kg of dry sludge per kg of COD removed. Finally, due to the presence of a relevant fraction of recalcitrant compounds in textile wastewater, a chemical oxidation step (e.g., ozone treatment) is required for enhancing SBBGR performance in order to permit the direct discharge.