The influence of chlorination timing and concentration on microbial communities in labyrinth channels: implications for biofilm removal

Abstract

Chlorination is an effective method to control biofilm formation in enclosed pipelines. To date, very little is known about how to control biofilms at the mesoscale in complex pipelines through chlorination. In this study, the dynamic of microbial communities was examined under different residual chlorine concentrations on the biofilms attached to labyrinth channels for drip irrigation using reclaimed water. The results indicated that the microbial phospholipid fatty acids, extracellular polymeric substances, microbial dynamics, and the ace and Shannon microbial diversity indices showed a gradual decrease after chlorination. However, chlorination increased microbial activity by 0.5–19.2%. The increase in the relative abundances of chloride-resistant bacteria (Acinetobacter and Thermomonas) could lead to a potential risk of chlorine resistance. Thus, keeping a low chlorine concentration (0.83 mg l⁻¹ for 3 h) is effective for controlling biofilm formation in the labyrinth channels.

Keywords:

• Biofilm
• chlorine
• drip irrigation
• emitter clogging
• labyrinth channel
• reclaimed water

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The authors are grateful for the financial support from the National Key Research Project [2017YFD0201504]; National Natural Science Fund of China [51621061, 51790531].