Strategies for mitigating chlorinated disinfection byproducts in wastewater treatment plants

Sofía Albolafio; Alicia Marín; Ana Allende; Francisca García; Pedro J Simón-Andreu; Manuel Abellán Soler; María I Gil

doi:10.1016/j.chemosphere.2021.132583

Strategies for mitigating chlorinated disinfection byproducts in wastewater treatment plants

Chemosphere. 2022 Feb;288(Pt 2):132583. doi: 10.1016/j.chemosphere.2021.132583. Epub 2021 Oct 15.

Authors

Sofía Albolafio¹, Alicia Marín¹, Ana Allende¹, Francisca García², Pedro J Simón-Andreu³, Manuel Abellán Soler³, María I Gil⁴

Affiliations

¹ Research Group on Microbiology and Quality of Fruit and Vegetables, Food Science and Technology Department, CEBAS-CSIC, Campus Universitario de Espinardo, Murcia, Spain.
² Acciona Agua, S.A.U., Spain.
³ Entidad Regional de Saneamiento y Depuración de Murcia (ESAMUR), Avda. Juan Carlos I, s/n. Ed. Torre Jemeca, 30009, Murcia, Spain.
⁴ Research Group on Microbiology and Quality of Fruit and Vegetables, Food Science and Technology Department, CEBAS-CSIC, Campus Universitario de Espinardo, Murcia, Spain. Electronic address: migil@cebas.csic.es.

PMID: 34662631
DOI: 10.1016/j.chemosphere.2021.132583

Abstract

A case study of 15 wastewater treatment plants (WWTPs) at a full-scale was assessed for the risks of disinfection byproduct (DBP) formation, mainly the regulated trihalomethanes (THMs) and haloacetic acids (HAAs) and chlorate as an inorganic byproduct regulated recently in the EU. Raw wastewater from large, medium/small urban areas were treated with single or combined disinfection processes (i.e., chlorine, peracetic acid (PAA) and ultraviolet (UV) radiation). Sampling was executed once a month over seven months for the medium/small WWTPs and twice a month for the large ones. Due to the potential risk of SARS-CoV-2 contaminated wastewater, several inactivation methods were examined before the DBP analysis. Due to the inactivation step, the stability of THM4 and HAA9 suffered reductions, monitoring their presence only in the effluents after the disinfection treatments. In contrast, chlorate levels remained unchanged after the inactivation treatment; thus both raw wastewater and effluents were examined for their occurrence before disinfection treatments. Results showed that chlorate residues in the raw wastewater varied greatly from undetected levels to as high as 42.2 mg L^-1. As the continuous monitoring of DBPs was performed, a positive correlation with chlorine or chlorine/UV was found. Changes in the physicochemical parameters indicated that the quality of the raw wastewater varied considerably depending on the WWTPs, and it influenced byproduct formation. In all WWTPs, chlorine alone or combined with UV significantly increased the presence of THMs, HAAs, and chlorate levels in the treated effluents. When the same WWTPs changed to PAA or PAA/UV, DBPs were diminished completely. This study highlights the risk of chlorate residues in raw wastewater during the pandemic. It also showed how the chemical risks of DBP formation could be reduced by changing the chlorinated disinfection technologies to PAA or PAA/UV, particularly if reclaimed water is intended for agricultural irrigation to minimize DBP residues.

Keywords: Chlorate; Chlorine; Haloacetic acids; PAA; Trihalomethanes; UV.

MeSH terms

COVID-19*
Disinfection
Humans
SARS-CoV-2
Water Purification*