Study towards understanding foaming and foam stability in urban lakes
Reshmi Das1, H N Chanakya1, Lakshminarayana Rao1
1Centre for Sustainable Technologies, Indian Institute of Science, Bangalore, India.
Journal of Environmental Management
|September 9, 2022
Summary
Untreated sewage causes foaming in Bellandur Lake due to surfactants. Phosphorus and specific bacteria, particularly Flavobacteriia, contribute to foam stability, impacting aquatic ecosystems.
Area of Science:
- Environmental Science
- Microbiology
- Water Quality Assessment
Background:
- Foaming water bodies are a global concern, disrupting ecosystems and daily life.
- Surface water foaming phenomena are not adequately studied, despite their widespread nature.
- Bellandur Lake in South India experiences significant foaming events.
Purpose of the Study:
- Investigate the sources and concentration of surfactants in Bellandur Lake.
- Determine the effect of phosphorus on foaming.
- Analyze the role of bacteria and their synergy with surfactants in foam stability.
Main Methods:
- Collected water samples from Bellandur Lake.
- Measured anionic surfactant concentration and surface tension.
- Quantified phosphorus concentration.
- Conducted foam stability studies with mixed bacteria.
Main Results:
- Untreated sewage identified as a major pollution source, introducing surfactants.
- Anionic surfactant concentration measured at 17 ± 3 ppm; surface tension around 50 mN/m.
- High phosphorus concentration (10 ± 3 ppm) primarily from feces and urine, indirectly affecting surfactants.
- Filamentous bacteria, especially from the Flavobacteriia family, in their stationary phase, significantly enhance foam stability.
Conclusions:
- Untreated sewage and associated surfactants are primary drivers of Bellandur Lake foaming.
- Phosphorus and specific bacterial communities, notably Flavobacteriia, play a crucial role in foam formation and stability.
- Further research is needed to understand and mitigate foaming in surface water bodies.
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