Degradation of Antibiotic Activity during UV/H₂O₂ Advanced Oxidation and Photolysis in Wastewater Effluent

Abstract

Trace levels of antibiotics in treated wastewater effluents may present a human health risk due to the rise of antibacterial activity in the downstream environments. Advanced oxidation has a potential to become an effective treatment technology for transforming trace antibiotics in wastewater effluents, but residual or newly generated antibacterial properties of transformation products are a concern. This study demonstrates the effect of UV photolysis and UV/H2O2 advanced oxidation on transformation of 6 antibiotics, each a representative of a different structural class, in pure water and in two different effluents and reports new or confirmatory photolysis quantum yields and hydroxyl radical rate constants. The decay of the parent compound was monitored with HPLC/ITMS, and the corresponding changes in antibacterial activity were measured using bacterial inhibition assays. No antibacterially active products were observed following treatment for four of the six antibiotics (clindamycin, ciprofloxacin, penicillin-G, and trimethoprim). The remaining two antibiotics (erythromycin and doxycycline) showed some intermediates with antibacterial activity at low treatment doses. The antibacterially active products lost activity as the UV dose increased past 500 mJ/cm(2). Active products were observed only in wastewater effluents and not in pure water, suggesting that complex secondary reactions controlled by the composition of the matrix were responsible for their formation. This outcome emphasizes the importance of bench-scale experiments in realistic water matrices. Most importantly, the results indicate that photosensitized processes during high dose wastewater disinfection may be creating antibacterially active transformation products from some common antibiotics.

Performance of different advanced oxidation processes for tertiary wastewater treatment to remove the pesticide acetamiprid

“…In addition, the presence of alkalinity in the water causes TiO 2 to aggregate, reducing the area available for surface reactions. This is an effect seen previously for degradation of the pesticide metaldehyde where degradation was reduced from 93% to 45% in a low to high alkalinity water source . This was explained by a change in TiO 2 aggregate size from 3 to 450 µm.…”

“…Hydrogen peroxide photolysis was also assayed (UV/H 2 O 2 ) with an oxidant concentration of 25, 50, 100 mg L −1 . This system has been reported as effective in the degradation of micropollutants from wastewater effluents using UV lamps . The acetamiprid removal profile was similar for 50 and 100 mg H 2 O 2 L −1 in either DW (Fig.…”

Sunlight-induced degradation of fluoroquinolones in wastewater effluent: Photoproducts identification and toxicity

“…Indeed, Babić et al (2013) investigated the photolytic degradation of Ciprofloxacin (CIP), Enrofloxacin (ENR) and Norfloxacin (NOR) in simulated pharmaceutical industry wastewater. Other studies focused on the photocatalytic abatement of Ofloxacin (OFL) in secondary treated effluents (Michael et al, 2010), or on UV-A irradiation of 15-50 mg L À1 Moxifloxacin (MOX) solutions in deionized water (Van Doorslaer et al, 2013) or in hospital effluent (Van Doorslaer et al, 2015), as well as on 2 mg L À1 CIP in wastewater effluent under UV (Keen and Linden, 2013).…”

Fast Atmospheric Plasma Deposition of Bio‐Inspired Catechol/Quinone‐Rich Nanolayers to Immobilize NDM‐1 Enzymes for Water Treatment

“…[ 1 ] In addition to their relative ineffi ciency, advanced oxidation processes (i.e., UV or ozonation) currently in use can also lead to the generation of secondary metabolites which are even more toxic than their parental compounds. [ 2,3 ] As a consequence, antibiotic levels detected in environmental water are becoming of greater concern. As an example, amoxicillin, one of the most widely used antibiotic and considered as a priority micropollutant, was detected at concentrations ranging from 10 to 200 ng L −1 in environmental waters.…”