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A two-stage process for simultaneous thermophilic sludge digestion, pathogen control and metal leaching
R Narayanan1, T R Sreekrishnan
1Department of Biochemical Engineering and Biotechnology, Indian Institute of Technology, New Delhi, India.
Environmental Technology
|February 14, 2009
Summary
Developed microbial consortia effectively treat municipal sewage sludge by lowering pH and enabling simultaneous digestion, pathogen control, and metal leaching under thermophilic conditions.
Area of Science:
- Environmental Microbiology
- Biotechnology
- Waste Management
Background:
- Municipal sewage sludge poses significant disposal challenges.
- Existing sludge treatment methods often lack efficiency in pathogen reduction and resource recovery.
- Microbial consortia offer potential for novel bioremediation strategies.
Purpose of the Study:
- To develop and characterize microbial consortia for municipal sewage sludge treatment.
- To investigate a two-stage aerobic process for simultaneous sludge digestion, pathogen control, and metal leaching.
- To evaluate the efficacy of thermophilic and mild-thermophilic conditions in sludge bioremediation.
Main Methods:
- Development of an aerobic sulfur-oxidizing microbial consortium from sewage sludge.
- Acclimatization of the consortium to mild-thermophilic (45°C) and thermophilic (60°C) conditions.
- Implementation of a two-stage aerobic process using developed microbial cultures in 1.5 L reactors.
Main Results:
- A mild-thermophilic consortium reduced sludge pH from 7.0 to 2.0.
- A thermophilic consortium reduced sludge pH from 7.0 to 4.8 at 60°C.
- The two-stage process stabilized volatile suspended solids, eliminated coliforms, and leached 90-100% of copper, manganese, and zinc.
Conclusions:
- Novel microbial consortia can effectively treat municipal sewage sludge under thermophilic conditions.
- The developed two-stage aerobic process enables simultaneous sludge digestion, pathogen inactivation, and valuable metal recovery.
- This approach presents a promising sustainable solution for municipal wastewater treatment and resource management.
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