Effects of phosphate addition on the removal of disinfection by-product formation potentials by biological activated carbon filtration

Feifei Wang, Yulin Hu, Jiazheng Pan, Jie Zhou, Chiquan He, J. A.M.H. Hofman, Wenhai Chu, Jan Peter van der Hoek

Research output: Contribution to journalArticlepeer-review

Abstract

In drinking water treatment plants (DWTPs), the widely used biological activated carbon filters (BACFs), as the last barrier before disinfection, can remove dissolved organic matter (DOM) known as precursors of disinfection by-products (DBPs). Whether phosphate addition can improve water purification and DBP control of BACFs is still controversial. This study investigated short-term and long-term effects of phosphate addition on controlling DBP formation potentials (FPs) by BACFs via column and batch experiments. The BAC columns presented good water purification performance: they removed around 50 % DOM, nearly all fulvic acid-likes and humic acid-likes as well as 5 %–70 % chlor(am)innated THM4, HAA9 and HAN4 FPs (except chloraminated THM4 FPs), which was mainly contributed by aerobic bacteria not anoxic bacteria. Phosphate addition within 7–14 days further improved removals of DOM, aromatic organics, fluorescence fractions in DOM as well as HAA9 and HAN4 FPs (especially TCAA FP and TCAN FP) to different extent. However, this improvement did not last longer, and removals of DOM, aromatic organics, two fluorescence fractions (soluble microbial byproduct-likes and humic acid-likes) and DBP FPs decreased despite long-term phosphate addition. Oxic and anoxic batch experiments showed that the positive response of water purification to short-term phosphate addition was also mainly attributed to aerobic bacteria and not to anoxic bacteria. For example, the former decreased DOM and DBP FPs, while the latter increased protein- and tryptophan-like substances as well as chloraminated THM4 FPs. Phosphate addition resulted in EPS increase in anoxic reactors and decrease in oxic reactors. These results indicated that a high dissolved oxygen in BACFs may be helpful for water purification and DBP control. Overall, short-term phosphate addition into phosphorus-limited water is beneficial for BACFs to control DBPs while long-term addition has no effect. Therefore, an intermittent phosphate addition into BACFs is suggested to control DBPs in DWTPs.

Original languageEnglish
Article number163534
Number of pages14
JournalScience of the Total Environment
Volume882
Early online date20 Apr 2023
DOIs
Publication statusPublished - 15 Jul 2023

Bibliographical note

Funding Information:
This work was funded by Science and Technology Commission of Shanghai Municipality (NO. 20230714100 ) and State Key Laboratory of Pollution Control and Resource Reuse Foundation (NO. PCRRF19003 ).

Data access statement:
Data will be made available on request.

Keywords

  • Anoxic condition
  • Chloramination
  • Chlorination
  • Disinfection by-products
  • Oxic condition
  • Phosphate

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Waste Management and Disposal
  • Pollution

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