Comparative study of adsorption, thermally activated peroxymonosulfate and wet air oxidation for tetracycline removal and wastewater treatment
Ruwanthi Ranaweera, Xing Wu, Derrick Ng, Philipp Reineck, Jianhua Zhang, M. Williams, Linhua Fan, Zongli Xie
Abstract
Pharmaceuticals such as antibiotics residues in wastewater discharges are hazardous contaminants due to their ecotoxicity and significant risks to human health by stimulating the emergence of antimicrobial resistance. Therefore, these substances must be effectively abated or removed from wastewater streams prior to discharge into aquatic ecosystems. This study exclusively compares advanced oxidation technologies, including thermally activated sulfate-radical oxidation (PMS/Heat) and wet air oxidation (WAO), with conventional activated carbon (AC) adsorption for treating antimicrobial wastewater. For technology comparison, antibiotic removal performance under optimised conditions were considered. AC adsorption was performed with 200 mL tetracycline (TC) and 200 mg AC. PMS/Heat was performed with 200 mL TC, 5 mM PMS, and at 70 °C. WAO was tested at 120 °C, 2 bar, and 120 mM H₂O₂. The comparative study revealed that all three technologies demonstrated high TC removal (>95 %) from the synthetic wastewater. In terms of hospital and municipal wastewater treatment, WAO achieved the highest total organic carbon (TOC) and chemical oxygen demand (COD) removal, surpassing AC and PMS/Heat with an effectiveness order of WAO > AC > PMS/Heat. WAO removed 77.1 % COD and 72.6 % TOC from hospital wastewater, and 59.1 % COD and 53.6 % TOC from municipal wastewater. Additionally, WAO and AC adsorption efficiently removed the antimicrobials and other pharmaceuticals from municipal and hospital wastewaters below the detection limit of liquid chromatography-mass spectrometry (LC-MS). This research emphasises the applicability and potential improvements of these technologies in real-world scenarios to address the pressing issue of pharmaceutical contaminants and antimicrobial resistance. • PAC, WAO, and PMS/Heat removed >95 % tetracycline from synthetic wastewater. • WAO outperformed PAC and PMS/Heat in TOC and COD removal from real wastewater. • WAO and PAC effectively removed a variety of antimicrobials from real wastewater.