Flocculation, Ozonation, and Fenton's Process in the Treatment of Distillery Effluents

This paper reports the application of flocculation, Fenton's process, and ozonation on the depuration of distillery wastewaters. The treatment processes were analyzed separately; nevertheless, integration schemes were also considered. The commercial flocculant 923PWG led to up to 84% of total suspended solids (TSS) removal even if a very low chemical oxygen demand (COD) abatement was observed (<2%). The effect of hydrogen peroxide concentration and [H2O2]/[Fe2+] molar ratio were tested on the Fenton's process efficiency. Moreover, the H2O2 injection mode was still analyzed. Gathering up both COD degradation and biodegradability enhancement, it was possible to select the following operating conditions: [H2O2] = 0.5 M and [H2O2]/[Fe2+] = 10 (mol/mol), being the oxidant totally introduced at the beginning of the reaction. Ozonation showed poor results regarding organic matter removal; however, it seems to be an interesting methodology raising the effluent's biochemical oxygen demand (BOD5)/COD ratio. In fact, in the strategies involving the integration of ozonation with Fenton's process, it was possible to conclude that ozone oxidation did not improve COD degradation; nonetheless, it was essential to improve biodegradability, particularly when conducting ozonation (at pH = 3) after Fenton's process was revealed to be an interesting approach leading to an effluent amenable to further biodegradation. DOI: 10.1061/(ASCE)EE.1943-7870.0000527. (C) 2013 American Society of Civil Engineers.