Assessment of full-scale tertiary wastewater treatment by UV-C based-AOPs: Removal or persistence of antibiotics and antibiotic resistance genes?

Abstract

This research reports for the first time the full-scale application of different homogeneous Advanced Oxidation Processes (AOPs) (H 2 O 2 /UV-C, PMS/UV-C and PMS/Fe(II)/UV-C) for the removal of antibiotics (ABs) and antibiotic resistance genes (ARGs) from wastewater effluent at Estiviel wastewater treatment plant (WWTP) (Toledo, Spain). AOPs based on the photolytic decomposition of H 2 O 2 and peroxymonosulfate tested at low dosages (0.05-0.5 mM) and with very low UV-C contact time (4-18 s) demonstrated to be more efficient than UV-C radiation alone on the removal of the analyzed ABs. PMS (0.5 mM) combined with UV-C (7 s contact time) was the most efficient treatment in terms of AB removal: 7 out of 10 ABs detected in the wastewater were removed more efficiently than using the other oxidants. In terms of ARGs removal efficiency, H 2 O 2 /UV-C seemed the most efficient treatment, although PMS/UV-C and PMS/Fe(II)/UV-C were supposed to generate higher concentrations of free radicals. The results show that treatments with the highest removal of ABs and ARGs did not coincide, which could be attributed to the competition between DNA and oxidants in the absorption of UV photons, reducing the direct photolysis of the DNA. Whereas the photolytic ABs removal is improved by the generation of hydroxyl and sulfate radicals, the opposite behavior occurs in the case of ARGs. These results suggest that a compromise between ABs and ARGs removal must be achieved in order to optimize wastewater treatment processes.

Advanced Oxidation Processes for the Removal of Antibiotics from Water. An Overview

“…Very recently, Rodríguez-Chueca et al [217] have reported that AOPs, in general, improved the efficiency of UV-C on the removal of antibiotics. When applying the harshest operating conditions (0.5 mM dosage of oxidants and 7s of UV-C contact time), three antibiotics (ciprofloxacin, metronidazole, and sulfamethoxazole) were similarly removed using peroxymonosulfate and H 2 O 2 as oxidants, four antibiotics (azithromycin, clindamycin, ofloxacin, and trimethoprim) were removed more efficiently using peroxymonosulfate, and three (clarithromycin, sulfadiazine, and sulfapyridine) using H 2 O 2 .…”

UV-C Peroxymonosulfate Activation for Wastewater Regeneration: Simultaneous Inactivation of Pathogens and Degradation of Contaminants of Emerging Concern

“…This effect was attributed to the UV photons scavenger by oxidants in detriment to DNA photoabsorption, reducing the direct damage to the genes. In addition, the LOQ of the investigated genes was not reached probably due to the very low contact time (4 s of UV-C irradiance) [ 33 ], which were much lower than those covered in the present study (60 min of treatment time, corresponding to 300 s of UV-C irradiance).…”

“…UV-C driven SR-AOPs have been studied for the degradation of different contaminants and for the inactivation of several pathogens, but only few studies involve the use of complex matrices [ 14 , 15 , 31 , 32 , 33 ]. Mahdi-Ahmed et al (2014) reported Ciprofloxacin (CIP) oxidation by UV-based AOPs, comparing the performances of three oxidants, PMS, PS, and H 2 O 2 in DW and UWW.…”

Physico‐chemical processes

“…Rodriguez‐Chueca et al (2019) applied homogeneous AOPs (H 2 O 2 /UV‐C, PMS/UV‐C, and PMS/Fe(II)/UV‐C) in full‐scale to treat antibiotics and ARGs. To remove antibiotics, 0.5 mmol PMS with 7‐s UV‐C had the greatest removal rate.…”