Title
Effect of oxidation ditch and anaerobic-anoxic-oxic processes on CX3R-type disinfection by-product formation during wastewater treatment
Author
Peng, Liqi (Tongji University; Shanghai Institute of Pollution Control and Ecological Security)
Wang, Feifei (Shanghai University)
Zhang, Di (Tongji University; Shanghai Institute of Pollution Control and Ecological Security)
Fang, Chao (Tongji University; Shanghai Institute of Pollution Control and Ecological Security)
van der Hoek, J.P. (TU Delft Sanitary Engineering; Waternet) 
Chu, Wenhai (Tongji University; Shanghai Institute of Pollution Control and Ecological Security)
Date
2021
Abstract
The high chlorine dosages in wastewater treatment plants during the COVID-19 pandemic may result in increased formation of disinfection by-products (DBPs), posing great threat to the aquatic ecosystem of the receiving water body and the public health in the downstream area. However, limited information is available on the effect of biological wastewater treatment processes on the formation of CX3R-type DBPs. This study investigated the effect of oxidation ditch (OD) and anaerobic-anoxic-oxic (AAO), two widely used biological wastewater treatment processes, on the formation of five classes of CX3R-type DBPs, including trihalomethanes (THMs), haloacetic acids (HAAs), haloacetaldehydes (HALs), haloacetonitriles (HANs) and halonitromethanes (HNMs), during chlorination. Experimental results showed that biological treatment effectively reduced the dissolved organic carbon (DOC) and UV254, while it increased the dissolved organic nitrogen (DON), and therefore the ratio of DON/DOC. In addition, increases in the contents of soluble microbial product- and humic acid-like matters, and the transformation of high molecular weight (MW) fractions in the dissolved organic matter into low MW fractions were observed after OD and AAO processes. Although biological treatment effectively decreased the formation of Cl-THMs, Cl-HAAs, Cl-HANs and Cl-HNMs, the formation of DBCM, DBAA, BDCAA, DBCAA, DCAL, TCAL and DBAN (where C = chloro, B = bromo, D = di, T = tri) all increased significantly, due to the increased formation reactivity. Moreover, biological treatment increased the ratio of bromide/DOC and bromine incorporation into THMs, HAAs and DHANs except for HALs and THANs. Different from previous studies, this study revealed that biological treatment increased the formation of some DBPs, especially brominated DBPs, despite the efficient removal of organic matters. It provides insights into the DBP risk control in wastewater treatment, particularly during the COVID-19 pandemic.
Subject
Disinfection by-products
Wastewater disinfection
Oxidation ditch
Anaerobic-anoxic-oxic
Formation reactivity
To reference this document use:
http://resolver.tudelft.nl/uuid:e5edba67-1244-4285-bef6-90090c0f5840
DOI
https://doi.org/10.1016/j.scitotenv.2021.145344
Embargo date
2021-07-22
ISSN
0048-9697
Source
Science of the Total Environment, 770, 1-9
Bibliographical note
Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.
Part of collection
Institutional Repository
Document type
journal article
Rights
© 2021 Liqi Peng, Feifei Wang, Di Zhang, Chao Fang, J.P. van der Hoek, Wenhai Chu