Textile wastewater treatment by ozone integration in a sequencing batch biofilter granular reactor

Effluents from textile industries are usually characterized by the presence of high quantities of different pollutants, which are often intentionally designed to resist degradation (for example dyes). Therefore, traditional methods based on the combination of biological and simple physico-chemical treatments are not able to remove these refractory compounds. Ozone integration in a Sequencing Batch Biofilter Granular Reactor (SBBGR) could be considered as an optimal treatment. In fact, on the one hand, the setup of the biological reactor allows improving treatment stability and efficiency of this step. On the other hand, ozonation can be easily integrated, ensuing in a synergic chemical and biological oxidation. This paper compares the results obtained in the treatment of a textile wastewater by SBBGR alone and after ozone integration with a low ozone dose (i.e., 40 mg/l). For the latter one, successful removal of all the monitored analysed pollutants was achieved, with effluent concentrations amply below the limits for discharge in superficial water bodies. A strong synergic ozone-biological oxidation was noticed, with an ozone consumption of about one third of the chemical oxygen demand removed.