Journal
SCIENCE OF THE TOTAL ENVIRONMENT
Volume 805, Issue -, Pages -Publisher
ELSEVIER
DOI: 10.1016/j.scitotenv.2021.150285
Keywords
Microcystis aeruginosa; Chlorination; Growth phase; Disinfection-by product
Categories
Funding
- Ministry of Science and Technology, Taiwan [MOST-108-2221-E-003-MY3]
Ask authors/readers for more resources
This study investigated the effects of pre-chlorination on Microcystis aeruginosa-laden water in different growth phases and the formation of carbonaceous disinfection by-products. The results showed that chlorination at the exponential phase led to faster and stronger degradation of algal cells, resulting in more significant viability loss and the formation of disinfection by-products, especially trihalomethanes. Pre-chlorination played a key role in the in-situ formation of disinfection by-products, with precursors contributing differently at each growth phase.
Algal growth strongly affects the change in characteristics of algal organic matter (AOM) in algae-laden water. AOM has adverse effects on algal cell removal from natural water by coagulation-sedimentation, frequently results in the significant formation of disinfection by-products (DBPs), such as trihalomethanes (THMs) and haloacetic acids (HAAs). This study aimed to investigate the effects of pre-chlorination on Microcystis aeruginosa (MA)-laden water collected in exponential and decline phases and the corresponding in-situ formed carbonaceous DBPs (C-DBPs) within 10 min exposure time. An automated fluorescent cell counter was used to determine the changes in cell degradation and viability, and fluorescent organic matters were characterized. The results have shown that MA cells suffer a faster and stronger degradation in chlorination at the exponential phase to cause more pronounced viability loss (>70%) than that at the decline phase, resulting in more significant released AOM degradation and C-DBPs formation, especially for THMs formation. In chlorination, a significant degradation in SMP-like and HA-like substances occurs at the exponential phase, while AP-like and SMP-like organics are predominantly degraded at the decline phase. Both THM and HAA precursors play an important role towards in-situ formation of C-DBPs at the exponential phase while THM precursors are dominant at the decline phase. THMs formation decreases with increasing HAAs formation over time during chlorination at the exponential phase, but stagnant THMs and HAAs formation occurs at the decline phase. Intensified pre-chlorination at high dosing ratio (Cl-2:DOC = 1:1) favors to facilitate in-situ formation of THMs. It is concluded that algal growth phase impact on cell removal and C-DBPs formation should be concerned for intensified pre-chlorination towards MA-laden water for drinking water treatment. (C) 2021 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available