Occurrence and risk assessment of typical PPCPs and biodegradation pathway of ribavirin in wastewater treatment plants

Qixin Liu; Xuan Feng; Ning Chen; Fei Shen; Haichuan Zhang; Shuo Wang; Zhiya Sheng; Ji Li

doi:10.1016/j.ese.2022.100184

Occurrence and risk assessment of typical PPCPs and biodegradation pathway of ribavirin in wastewater treatment plants

Environ Sci Ecotechnol. 2022 May 3:11:100184. doi: 10.1016/j.ese.2022.100184. eCollection 2022 Jul.

Authors

Qixin Liu¹, Xuan Feng¹, Ning Chen¹, Fei Shen², Haichuan Zhang¹, Shuo Wang^{1

3

4}, Zhiya Sheng⁵, Ji Li^{1

3

4}

Affiliations

¹ Jiangsu Key Laboratory of Anaerobic Biotechnology, School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China.
² Laboratory of Instrumental Analysis, Jiangsu Wuxi Environmental Monitoring Center, Wuxi, 214121, China.
³ Jiangsu Engineering Laboratory for Biomass Energy and Carbon Reduction Technology, Jiangnan University, Wuxi, 214122, China.
⁴ Jiangsu College of Water Treatment Technology and Material Collaborative Innovation Center, Suzhou, 215009, China.
⁵ Department of Civil and Environmental Engineering, University of Alberta, Edmonton, T6G 2W2, Canada.

Abstract

A large number of pharmaceuticals and personal care products (PPCPs) persist in wastewater, and the consumption of PPCPs for COVID-19 control and prevention has sharply increased during the pandemic. This study investigated the occurrence, removal efficiency, and risk assessment of six typical PPCPs commonly used in China in two wastewater treatment plants (WWTPs). Ribavirin (RBV) is an effective pharmaceutical for severely ill patients with COVID-19, and the possible biodegradation pathway of RBV by activated sludge was discovered. The experimental results showed that PPCPs were detected in two WWTPs with a detection rate of 100% and concentrations ranging between 612 and 2323 ng L^-1. The detection frequency and concentrations of RBV were substantially higher, with a maximum concentration of 314 ng L^-1. Relatively high pollution loads were found for the following PPCPs from influent: ibuprofen > ranitidine hydrochloride > RBV > ampicillin sodium > clozapine > sulfamethoxazole. The removal efficiency of PPCPs was closely related to adsorption and biodegradation in activated sludge, and the moving bed biofilm reactor (MBBR) had a higher removal capacity than the anoxic-anaerobic-anoxic-oxic (AAAO) process. The removal efficiencies of sulfamethoxazole, ampicillin sodium, ibuprofen, and clozapine ranged from 92.21% to 97.86% in MBBR process and were relatively low, from 61.82% to 97.62% in AAAO process, and the removal of RBV and ranitidine hydrochloride were lower than 42.96% in both MBBR and AAAO processes. The discrepancy in removal efficiency is caused by temperature, hydrophilicity, and hydrophobicity of the compound, and acidity and alkalinity. The transformation products of RBV in activated sludge were detected and identified, and the biodegradation process of RBV could be speculated as follows: first breaks into TCONH₂ and an oxygen-containing five-membered heterocyclic ring under the nucleosidase reaction, and then TCONH₂ is finally formed into TCOOH through amide hydrolysis. Aquatic ecological risks based on risk quotient (RQ) assessment showed that PPCPs had high and medium risks in the influent, and the RQ values were all reduced after MBBR and AAAO treatment. Ranitidine hydrochloride and clozapine still showed high and medium risks in the effluent, respectively, and thus presented potential risks to the aquatic ecosystem.

Keywords: Biodegradation pathway; COVID-19 pandemic; Mass balance; Pollution load estimation; Ribavirin (RBV); Risk assessment.