Adsorption coupled with biodegradation removal of actual pharmaceutical wastewater: effect of reaction conditions and microbial community assessment

Abstract

Pharmaceutical wastewater underwent treatment through a combined process involving adsorption and biodegradation. Investigation into the relationship between influent chemical oxygen demand (COD) and dehydrogenase activity (DHA) revealed that the optimal influent COD concentration stood at 1500 mg L⁻¹, corresponding to the highest DHA value recorded at 126.85 μg_TF g⁻¹ h⁻¹. Operational parameters such as gas supply modes, influent patterns, and gas supply rates were systematically studied for their impact on biodegradation performance. Results demonstrated that the highest average removal rates for COD, UV₂₅₄, NH₃-N and NO₃⁻-N reached up to 96.97%, 79.77%, 73.00%, and 89.32%, respectively; and the lowest concentration of NO₂⁻-N in the effluent was 0.17 mg L⁻¹. The analysis of microbial community structure revealed that Proteobacteria and Bacteroidetes were the dominant phyla, while Pseudomonas and Flavobacterium comprised the majority at the genus level. This study highlights the promising potential of adsorption and biodegradation processes in effectively eliminating high-concentration organic contaminants originating from pharmaceutical plants.