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A Novel Bioreactor for High Density Cultivation of Diverse Microbial Communities
Published on: December 25, 2015
Microbial community changes with decaying chloramine residuals in a lab-scale system.
K C Bal Krishna1, Arumugam Sathasivan, Maneesha P Ginige
1Department of Civil and Construction Engineering, Curtin University, GPO Box U1987, Perth, WA 6845, Australia.
Water Research
|June 18, 2013
Summary
Managing chloramine disinfectant residuals in water systems is difficult. This study reveals heterotrophic bacteria, not nitrifiers, may be key to controlling chloramine decay and maintaining residuals.
Area of Science:
- Environmental Microbiology
- Water Treatment Chemistry
- Public Health Engineering
Background:
- Maintaining adequate chloramine residuals in water distribution systems is challenging, especially after nitrification begins.
- Current nitrification-focused strategies for managing chloramine decay have proven ineffective.
- Understanding the impact of chloramine decay and nitrification metabolites on microbial communities is crucial.
Purpose of the Study:
- To investigate the relationship between chloramine residuals, nitrification metabolites, and microbial community structure in simulated distribution systems.
- To identify key bacterial groups associated with different chloramine residual levels and nitrification stages.
- To explore alternative targets for effective chloramine residual management strategies.
Main Methods:
- Operated five laboratory-scale reactors in series to mimic a full-scale chloraminated water distribution system.
- Utilized culture-independent techniques, including cloning and quantitative PCR (qPCR), to characterize and quantify microbial communities.
- Monitored chloramine residuals across a range from high (2.18 mg/L) to low (0.03 mg/L).
Main Results:
- Distinct microbial communities were associated with varying chloramine residuals and nitrification stages.
- Bacterial classes Solibacteres, Nitrospira, Sphingobacteria, and Betaproteobacteria dominated at low chloramine levels, while Actinobacteria and Gammaproteobacteria were prevalent at higher levels.
- Heterotrophic bacteria, particularly Sphingomonas, increased with nitrification, and nitrification alone did not fully explain observed chloramine decay rates.
Conclusions:
- Chloramine residuals and nitrification metabolites significantly influence microbial community composition in water distribution systems.
- Heterotrophic bacteria, rather than nitrifying bacteria, may be more critical for understanding and controlling chloramine decay.
- Future strategies for managing chloramine residuals should consider targeting heterotrophic bacterial populations.
Keywords:
Chloramine decayChloramine residualsHeterotrophic microbesMicrobial communitiesNitrificationMore Related Videos
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