Fate of artificial sweeteners through wastewater treatment plants and water treatment processes.

Jinju Geng,Yuhang Ren,Shaoli Li,Yingying Fu,Cong Jiang,Hongqiang Ren,Xingsheng Gao,Gang Wu

doi:10.1371/journal.pone.0189867

Jinju Geng, Yuhang Ren + Show 6 more

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https://doi.org/10.1371/journal.pone.0189867

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Abstract

Five full-scale wastewater treatment plants (WWTPs) in China using typical biodegradation processes (SBR, oxidation ditch, A2/O) were selected to assess the removal of four popular artificial sweeteners (ASs). All four ASs (acesulfame (ACE), sucralose (SUC), cyclamate (CYC) and saccharin (SAC)) were detected, ranging from 0.43 to 27.34μg/L in the influent. Higher concentrations of ASs were measured in winter. ACE could be partly removed by 7.11–50.76% through biodegradation and especially through the denitrifying process. The A2/O process was the most efficient at biodegrading ASs. Adsorption (by granular activated carbon (GAC) and magnetic resin) and ultraviolet radiation-based advanced oxidation processes (UV/AOPs) were evaluated to remove ASs in laboratory-scale tests. The amounts of resin adsorbed were 3.33–18.51 times more than those of GAC except for SUC. The adsorption ability of resin decreased in the order of SAC > ACE > CYC > SUC in accordance with the pKa. Degradation of ASs followed pseudo-first-order kinetics in UV/H2O2 and UV/PDS. When applied to the secondary effluent, ASs could be degraded from 30.87 to 99.93% using UV/PDS in 30 minutes and UV/PDS was more efficient and economic.

Highlights

Artificial sweeteners (ASs) are popular sugar substitutes used in food, beverages, pharmaceuticals and personal care products [1]
The concentrations of artificial sweeteners (ASs) in influent in winter exceeded those in summer by factors of 4.3~6.3, which is different from a former study in which CYC and SAC concentrations were higher in winter and ACE and SUC concentrations were higher in summer in an open coast system in HK [12]
This phenomenon may be explained by consumption habits and lower removal efficiency by biodegradation in Wastewater treatment plants (WWTPs) in winter

Summary

Introduction

Artificial sweeteners (ASs) are popular sugar substitutes used in food, beverages, pharmaceuticals and personal care products [1]. ASs have been listed as emerging contaminants, and ACE is among the anthropogenic trace contaminants with the highest concentrations in ground water and surface water as well as drinking water [2]. Wastewater treatment plants (WWTPs) are a source of ASs entering the aqueous environment. Surveys of this occurrence have become plentiful since the first research reporting the existence of SUC in rivers and WWTP effluents [3]. Concentrations of ASs from nano- to microgram levels in wastewater influents and effluents have been reported in European countries [2, 4,5,6] and in the USA [7], with variations between countries.

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