Cavitationally induced biodegradability enhancement of a distillery wastewater.

Hydrodynamic cavitation (HC) was evaluated as a pretreatment option for the complex/recalcitrant biomethanated distillery wastewater (B-DWW). The effect of various process parameters such as inlet pressure, dilution and reaction time on reduction of COD/TOC and enhancement of biodegradability index (BI:BOD(5):COD ratio) of the B-DWW was studied with an aim to maximize the biodegradability index and reducing the toxicity of the distillery wastewater. It was observed that higher operating pressure (13 bar) yielded the maximum BI whereas the lower pressure (5 bar) is suitable for the reduction in the toxicity of B-DWW. The toxicity of the distillery wastewater was analyzed by measuring the COD, TOC and color of the wastewater sample. The HC pretreatment under optimized conditions leads to a BI of 0.32, COD and TOC reduction of 32.24% and 31.43%, respectively along with a color reduction by 48%. These results indicate the potential of HC as a pretreatment option for enhancing the biodegradability index of the recalcitrant wastewater such as B-DWW along with reduced toxicity of wastewater as observed from COD, TOC and color reduction profile under optimized conditions.