Nano catalytic ozonation of biomethanated distillery wastewater for biodegradability enhancement, color and toxicity reduction with biofuel production

The effectiveness of O3, O3/Fe2+, and O3/nZVI processes on biomethanated distillery wastewater (BMDWW) was evaluated in terms of biodegradability index (BI) enhancement, biofuel production, COD, color & toxicity reduction. A significant increase in biodegradability, COD, color and toxicity reduction was observed in O3/nZVI compared with O3, O3/Fe2+ due to more hydroxyl radical production. The O3/nZVI pretreated wastewater with enhanced BI (up to 0.71) showed 60% COD removal with additional biogas generation (64% methane content). From the Gas Chromatography Mass Spectrometry (GC-MS) analysis, 18 foremost organic compounds were predominantly detected in the raw distillery wastewater. The disappearance of the corresponding FTIR (Fourier Transform Infrared Spectroscopy) & GC-MS spectra during pretreatment processes signified the degradation or transformation of the recalcitrant present in the distillery wastewater. Subsequent (AnO + AO, AO) of pretreated BMDWW resulted in biodegradation rate enhancement by (1.83, 1.67), (3.5, 2.4) and (4.7, 2.9) times for O3, O3/Fe2+ and O3/nZVI processes respectively. [Display omitted] •nZVI particles and Fe2+ catalyzed ozone pretreatment for biodegradability enhancement.•nZVI synthesized and characterized using SEM, TEM and XRD .•8 foremost organic compounds were detected in the pharmaceutical wastewater .•FTIR & GC-MS analysis confirms the cleavage of recalcitrant organic compounds .•Microbial growth kinetic parameters confirm the increased rate of biodegradation .