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Single-stage autotrophic nitrogen-removal process using a composite matrix immobilizing nitrifying and
Y Aoi1, Y Shiramasa, E Kakimoto
1Department of Chemical Engineering, Waseda University, 3-4-1 Ohkubo, Shinjuku-ku, Tokyo, 169-8555, Japan. yoshiteruaoi@toki.waseda.jp
Applied Microbiology and Biotechnology
|February 5, 2005
Summary
A new single-stage process efficiently removes ammonia from wastewater using immobilized nitrifying and sulfur-denitrifying bacteria. This innovative method converts ammonia to nitrogen gas within one reactor, simplifying wastewater treatment.
Area of Science:
- Environmental Microbiology
- Wastewater Treatment Engineering
- Biogeochemical Cycles
Background:
- Conventional nitrogen removal processes often require multiple stages and specific operational conditions, increasing complexity and cost.
- Autotrophic nitrogen removal offers a sustainable alternative by utilizing inorganic electron donors, but efficient single-stage implementation remains a challenge.
Purpose of the Study:
- To develop and demonstrate a novel single-stage autotrophic nitrogen removal process.
- To investigate the feasibility of integrating nitrification and sulfur-denitrification within a single reactor using composite immobilized biomass.
- To evaluate the microbial community structure and performance of the developed system.
Main Methods:
- Development of a composite immobilized biomass matrix using a Fe-Ni fibrous slag material.
- Immobilization of nitrifying bacteria in the outer layer and sulfur-denitrifying bacteria with elemental sulfur in the inner layer.
- Real-time PCR was used to assess the spatial distribution of ammonia-oxidizing and denitrifying bacteria within the matrix.
Main Results:
- Successful demonstration of complete ammonia conversion to N2 in a single reactor under both batch and continuous-feed conditions.
- Observed spatial stratification of nitrifying and denitrifying bacteria within the composite matrix after several months.
- The process effectively coupled nitrification and anoxic denitrification, utilizing elemental sulfur as the electron donor.
Conclusions:
- The developed single-stage autotrophic nitrogen removal process is effective and simplifies wastewater treatment.
- The Fe-Ni fibrous slag matrix supports the spatial stratification and function of distinct microbial communities for nitrogen removal.
- This technology shows significant potential for broad application in various wastewater treatment scenarios due to its operational simplicity.