Effect of Activated Sludge on the Degradation of 2-Ethylhexyl 4-Methoxycinnamate and 2-Ethylhexyl 4-(Dimethylamino)Benzoate in Wastewater

Alicja Gackowska,Waldemar Studziński

doi:10.1007/s11270-020-04516-y

Alicja Gackowska, Waldemar Studziński

Open Access

https://doi.org/10.1007/s11270-020-04516-y

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Abstract

Incomplete removal of organic pollutants during wastewater treatment is one of the main routes to introduce micro-pollutants into the environment. This group of pollutants includes, among others, UV filters. Commonly used UV filters are 2-ethylhexyl 4-methoxycinnamate (EHMC) and 2-ethylhexyl 4-(dimethylamino)benzoate (ODPABA). Due to the lipophilic character, these compounds can accumulate in sludge. The effects of activated sludge on the removal of EHMC and ODPABA from wastewater have been investigated in this study. It was shown that both UV filters tend to accumulate in the sludge. The concentration of UV filters in sludge increased with the increase of activated sludge dose and time of process. It was checked whether EHMC and ODPABA were transformed in activated sludge. A gas chromatograph coupled with a mass spectrometry detector (GC-MS) was used to identify products. In the case of EHMC, ethylhexyl alcohol (EHA) and the Z-EHMC isomer were identified. Methyl-4-aminobenzoic acid (MPABA) was identified as ODPABA degradation product. Elimination of EHMC and ODPABA from wastewater mainly proceeds by adsorption of these pollutants in the sludge. Filters present in wastewater and sludge undergo transformations.

Highlights

Organic UV filters are used to protect the skin against the harmful effects of sunlight
Our research indicates that the effectiveness of ethylhexyl 4methoxycinnamate (EHMC) and ODPABA removal depends on the dose of activated sludge
Due to the lipophilic properties of EHMC and ODPABA, these compounds tend to accumulate in sludge

Summary

Introduction

Organic UV filters are used to protect the skin against the harmful effects of sunlight. Chemical UV filters get directly into the environment as a result of washing away from the skin, washing clothes, while practicing water sports, as well as indirectly with municipal or industrial wastewater These compounds have been identified as impurities in wastewater (Plagellat et al 2006; Moeder et al 2010; Zhang et al 2011; Tsui et al 2014a; Ekpeghere et al 2016), lakes (Poiger et al 2004; Balmer et al 2005), and rivers (Fent et al 2010) at levels of ng L−1 and μg L−1 even in tap water (Díaz-Cruz et al 2012; da Silva et al 2015). Recreational activities would be the main sources of this compound instead of wastewater effluent discharge

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