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Methane microprofiles in a sewage biofilm determined with a microscale biosensor
L R Damgaard1, L P Nielsen, N P Revsbech
1Department of Microbial Ecology, University of Aarhus, B.540 Ny Munkegade, DK-8000 Aarhus C, Denmark. lars.damgaard@biology.au.dk
Water Research
|April 25, 2001
Summary
This study measured methane in sewage biofilms using a methane microsensor. Aerobic respiration controlled methane export, while nitrate and sulfate inhibited methane production.
Area of Science:
- Environmental microbiology
- Biogeochemical cycling
Background:
- Sewage biofilms are complex microbial ecosystems.
- Understanding methane dynamics in biofilms is crucial for wastewater treatment and greenhouse gas mitigation.
Purpose of the Study:
- To investigate methane microprofiles and methanogenesis within sewage biofilms.
- To assess the impact of oxygen, nitrate, and sulfate on methane production and consumption.
Main Methods:
- Utilized a high-resolution methane microsensor to measure methane concentration profiles.
- Established and incubated a model sewage biofilm with sodium acetate.
- Quantified methanogenesis and aerobic respiration rates.
Main Results:
- Methane accumulated to 175 µmol l⁻¹ at 3 mm depth in fresh biofilm.
- Aerobic respiration (0.80 µmol m⁻² s⁻¹) exceeded methanogenesis (0.14 µmol m⁻² s⁻¹), controlling methane export.
- Nitrate and sulfate significantly inhibited methanogenesis at varying concentrations and depths.
Conclusions:
- Methane microsensors are powerful tools for studying microhabitats with concurrent methane production and consumption.
- Aerobic respiration plays a key role in regulating methane release from sewage biofilms.
- Nitrate and sulfate act as inhibitors of methanogenesis in these environments.