Tracking pollutants in a municipal sewage network impairing the operation of a wastewater treatment plant

Mariana F T Sá; Verónica Castro; Ana I Gomes; Daniela F S Morais; Rui V P S Silva Braga; Isabel Saraiva; Bianca M Souza-Chaves; Minkyu Park; Victoria Fernández-Fernández; Rosario Rodil; Rosa Montes; José Benito Quintana; Vítor J P Vilar

doi:10.1016/j.scitotenv.2021.152518

Tracking pollutants in a municipal sewage network impairing the operation of a wastewater treatment plant

Sci Total Environ. 2022 Apr 15:817:152518. doi: 10.1016/j.scitotenv.2021.152518. Epub 2022 Jan 4.

Affiliations

¹ Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
² Department of Analytical Chemistry, Nutrition and Food Sciences, Institute of Research on Chemical and Biological Analysis (IAQBUS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain.
³ Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: ana.isabelgomes@fe.up.pt.
⁴ Efacec Engenharia e Sistemas S.A. (Unidade de Negócios Ambiente), Rua Eng. Frederico Ulrich - Guardeiras, Apartado 3003, 4474-907 Moreira da Maia, Portugal.
⁵ Department of Chemical & Environmental Engineering, University of Arizona, 1133 E James E Rogers Way, Harshbarger 108, Tucson, AZ 85721-0011, USA; CNPq - National Council for Scientific and Technological Development, Brazil.
⁶ Department of Chemical & Environmental Engineering, University of Arizona, 1133 E James E Rogers Way, Harshbarger 108, Tucson, AZ 85721-0011, USA.
⁷ Department of Analytical Chemistry, Nutrition and Food Sciences, Institute of Research on Chemical and Biological Analysis (IAQBUS), Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain. Electronic address: jb.quintana@usc.es.
⁸ Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), Departamento de Engenharia Química, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: vilar@fe.up.pt.

PMID: 34995583
DOI: 10.1016/j.scitotenv.2021.152518

Abstract

This work provides a screening of organic contaminants and characterization of the dissolved organic matter in the sewer network until the municipal wastewater treatment plant (WWTP), identifying the network areas with a higher degree of contamination and their impact on the WWTP performance, particularly in the activated sludge reactor. Three monitoring campaigns were carried out at six selected locations of the sewage system (PVZ-1, PVZ-2, PS-F, PS-VC, CP-VC, and PS-T), influent (WWTP_INF) and effluent (WWTP_EFF) of the WWTP. Advanced analytical techniques were employed, namely excitation/emission matrix fluorescence-parallel factor analysis (EEM-PARAFAC), size exclusion chromatography with organic carbon detector (SEC-OCD), and liquid chromatography with high-resolution-mass spectrometric detection (LC-HRMS). EEM-PARAFAC showed higher fluorescence intensity for the protein-like component (C2), particularly at CP-VC (near seafood industries) associated with the presence of surfactants (~50 mg/L). SEC-OCD highlighted the WWTP efficiency in removing low molecular weight acids and neutrals. LC-HRMS tentatively identified 108 compounds of emerging concern (CEC) and similar detection patterns were obtained for all wastewater samples, except for PVZ-2 (lower detection), many of which occurred in the effluent. Eight CECs included on relevant Watch-Lists were detected in all WWTP_EFF samples. Furthermore, 111 surfactants were detected, the classes more frequently found being alcohol ethoxylates (AEOs), nonylphenol polyethoxylates (NPEOs) and linear alkylbenzene sulphonates (LAS). The continuous presence of LAS and NPEOs allied to surfactants concentrations in the WWTP_INF of 15-20 mg/L, with CP-VC location (linked with food industries) as an important contributor, explain the morphological changes in the activated sludge and high LAS content in the dewatered sludge, which may have impacted WWTP performance.

Keywords: Contaminants of emerging concern (CEC); EEM-PARAFAC analysis; Industrial pollution hotspots; LC-QTOF; Suspect screening; surfactans.

MeSH terms

Environmental Pollutants* / analysis
Sewage / chemistry
Wastewater / chemistry
Water Pollutants, Chemical* / analysis
Water Purification* / methods

Substances

Environmental Pollutants
Sewage
Waste Water
Water Pollutants, Chemical