Enhancement of the removal of the residual activepharmaceutical ingredients from wastewater : adsorption studies on three common antibiotics

Abstract

Micropollutants, like pharmaceuticals, are a potential risk to human health and the ecosystems. Pharmaceutical factories are significant local point sources that might release increased pharmaceutical concentrations to the environment which might have global consequences, such as the development of antimicrobial resistance. The pharmaceutical production has been shifting to the emerging countries where the treatment of wastewater can be negligible, and elimination of pharmaceuticals from the wastewater is therefore crucial. The aim of this master’s thesis was to study treatment techniques to obtain maximal removal efficiency for sulfamethox-azole (SMX), trimethoprim (TMP) and ciprofloxacin (CIP). Activated carbon was chosen for further studies, and two batch experiments, and a fixed-bed column experiment was conducted with granular activated carbon (GAC) to study the removal of the three antibiotics. Results were obtained analyzing total organic carbon, UV absorbance (at 254 nm) or using high-performance liquid chromatography tandem mass spectrometry. TMP was the most efficiently adsorbed onto GAC in the batch experiments, and SMX in the column experiment. The adsorption bed capacity of GAC was 23,48 mg SMX / g GAC, 21,52 mg TMP / g GAC and 21,60 mg CIP / g GAC. The adsorption data of SMX and CIP were best described by the Freundlich isotherm model which indicated that the adsorption was favorable but somewhat weak. In the column experiment, the breakthrough of the three antibiotics occurred on the 8th day for TMP and CIP, and on the 9th day for SMX. For the complete eradication of pharmaceuticals from wastewater two or several conventional and advanced technologies should be applied, such as the activated carbon treatment, to minimize the potential risk to human health and the ecosystems.