Pharmaceutical wastewater treatment using granular activated carbon and UV/H2O2 processes: Experimental analysis and modelling

The treatment of a synthetic pharmaceutical wastewater was studied using granular activated carbon (GAC) adsorption, UV/H2O2 process, and their combination. Experimental results reveal that GAC adsorption alone has 79% efficiency in total organic carbon (TOC) removal in 10min breakthrough time with the dosage of 333.33mgactivated carbon/L. The adsorption data are fitted well with the Langmuir adsorption isotherm. The UV/H2O2 process alone at 6h hydraulic retention time with optimum dosage of 4.25mgH2O2/mgCOD shows 29 and 26% TOC reduction using 185 and 254nm UV lamps, respectively. The kinetic modelling of the UV254/H2O2 process is developed using chemical oxygen demand (COD) and TOC as lumped parameters. A good agreement between model predictions and experimental data is confirmed. In combined processes, pre-treated pharmaceutical wastewater by UV254/H2O2 followed by GAC adsorption process along with the desorption of contaminants from GAC and the subsequent treatment of the condensed steam by UV254/H2O2 process leads to 82 % TOC removal efficiency. On the other hand, the GAC adsorption along with UV254/H2O2 treatment of regenerant (condensed steam) from the desorption process leads to 88 % TOC removal at optimum conditions.