TREATMENT OF PHARMACEUTICAL WASTEWATER USING ADVANCED OXIDATION PROCESSES

Abstract

There has been a rapid increase in pharmaceutical industries in the past few years. These industries utilize natural water as a raw material in distinct manufacturing processes. The wastewater generated from manufacturing processes contains mainly the concentration of manifold chemicals, antibiotics, hormones, etc. Discharge of these chemicals in the aquatic environment has resulted in water pollution, bioaccumulation in aquatic organisms, death of microorganisms, disruption of nutrient cycling, and an effect over ecosystem functions. Recently, Advanced Oxidation Processes (AOPs) such as photocatalysis, Fenton, Sonication and their integrated processes have gained attention for degradation of recalcitrant compounds. Among pharmaceutical compounds, the major concern is towards antibiotics such as amoxicillin (AMX), and β-blocker like Atenolol (ATL). The present study dealt with degradation of pharmaceutical drugs using AOPs. The variable parameters regulating AOPs viz. pH, H2O2 concentration, FeSO4, TiO2 etc. were optimised during the study, and degradation of the order of 80% for AMX and 90% ATL, respectively, was recorded. The optimum conditions of Fenton treatment were further used to perform treatment integrated with UV and ultrasound. Similarly, optimized conditions from photocatalysis with H2O2 in case of AMX were utilized to perform photocatalysis and sono-photocatalysis experiments. It was observed that exposure to solar or UV light is necessary for effective degradation of pharmaceutical drugs, especially with respect to rate of treatment. Higher rate of degradation ensures treatment of larger volumes of pharmaceutical effluents. The optimised conditions of AOPs were found to be evenly effective for treatment of real pharmaceutical wastewater. The HPLC analysis confirmed no formation of intermediate product of degradation confirming that the AOPs lead to mineralisation of AMX and ATL with no residual toxicity. Photo-Fenton process has an ability to completely degrade AMX as well as ATL in lesser time duration as compared to other treatment processes. Response Surface Methodology (RSM) was used to optimize and validate the treatment processes and the model represented a good fit with the observed results. The study concluded that AOPs can be employed for treating pharmaceutical wastewater for complete degradation of residual antibiotics to manage the mounting problem of antibiotic-resistant bacteria and anti-biotic resistant genes in environment. Application of AOPs under solar light is recommended for overcoming the cost where energy input is a limitation, particularly in developing countries.