Related Experiment Video

Updated: Sep 1, 2025

Manganese Oxide Nanoparticle Synthesis by Thermal Decomposition of ManganeseII Acetylacetonate
09:02

Manganese Oxide Nanoparticle Synthesis by Thermal Decomposition of ManganeseII Acetylacetonate

Published on: June 18, 2020

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Chloramine Prevents Manganese Accumulation in Drinking Water Pipes Compared to Free Chlorine by Simultaneously

Guiwei Li1, Yuliang Su2, Bin Wu2

  • 1Key Laboratory of Drinking Water Science and Technology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China.

Environmental Science & Technology
|August 17, 2022
PubMed

Insights

Disinfectant type significantly impacts manganese deposit formation in drinking water pipes. Chloramination effectively prevents manganese buildup, unlike chlorination, offering insights for better water quality management.

Area of Science:

  • Environmental Science
  • Water Treatment Engineering
  • Microbiology

Background:

  • Residual manganese(II) in finished water can oxidize and form manganese oxide (MnO) deposits in drinking water pipes.
  • Microbial activity is a known driver of manganese deposit formation in pipes lacking disinfection.

Purpose of the Study:

  • To investigate the influence of disinfectant type and dose on manganese(II) oxidation and manganese oxide accumulation in drinking water pipes.
  • To understand the mechanisms by which different disinfectants affect manganese deposit formation.

Main Methods:

  • Long-term pipe experiments using water from a full-scale water treatment plant.
  • Comparison of manganese(II) oxidation and MnO accumulation under free chlorination and chloramination.
  • Assessment of disinfectant cessation and resumption effects on manganese deposit dynamics.

Main Results:

  • Free chlorine (1.0 mg/L) rapidly initiated Mn(II) oxidation and MnO accumulation via autocatalysis and adsorption.
  • Chloramination (1.0 mg/L) effectively inhibited MnO accumulation by suppressing microbial oxidation.
  • Low-dose free chlorine (0.3 mg/L) reduced deposits but less effectively than chloramination.
  • Disinfection cessation led to biotic Mn(II) oxidation, which was re-inhibited upon resumption.
  • Iron(III) stabilized MnO deposits, while humic acid promoted resuspension.

Conclusions:

  • Disinfectant choice critically regulates manganese oxide formation in drinking water systems.
  • Chloramination presents a promising strategy for controlling manganese deposits in pipes.
  • Understanding disinfectant-microbe-manganese interactions is key to optimizing water disinfection for deposit control.
Keywords:
chloraminedepositsdrinking water distributionfree chlorinemanganesemicrobialoxidation

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