Isolation of specific nitrogen-bacteria and studies on their applications for simultaneous carbon and nitrogen removal from wastewater
Date Issued
2006
Date
2006
Author(s)
Wu, Yi-Lung
DOI
zh-TW
Abstract
This research is to estimate the feasibility of a system using specific nitrogen bacteria ─ the heterotrophic nitrifiers, to remove nitrogen from swine wastewater with better performance. Another purpose is to improve nitrogen and COD removal from wastewater and reduce the overall operation cost. By concerning the possibly lower competitivity of these microorganisms under realistic environment, the immobilization technique is introduced to increase their chance to survive and make the single-reactor nitrification/denitrification process practicable. Isolation and immobilization of native heterotrophic nitrification bacteria with or without simultaneously nitrifying and denitrifying ability will be carried out and immobilized or co-immobilized with aerobic denitrifiers if needed, performing single-reactor SND, TKN and ammonium can be converted directly into nitrogen gas without an additional anoxic tank. This single reactor has some advantages than the traditional ones: the alkalinity produced from denitrification process can neutralize the acidity formed from nitrification activity, so that the range of pH change is mitigated. Further more, less or no additional carbon source may be required since the organic carbon demand for the denitrification reaction is directly consumed from wastewater COD, so that the purpose of removing nitrogen and COD can be achieved simultaneously, and the total operation cost will be reduced. Besides, we also intend to apply the heterotrophic nitrifiers to improve the nitrification and COD removal efficiency of those reactors containing high-level COD.
Presently, over 200 strains of bacteria have been isolated from paddy field drains, soil and swine wastewater treatment systems respectively. 10 strains of them showed significant heterotrophic nitrification and were isolated and purified. Culture purity, scientific name and relative gene information of these isolated heterotrophic nitrifiers were determined by applying their 16s rDNA sequencing data to NCBI 16srDNA database. Biochemical characteristics of isolated microbes have also been carried out, the strain slg-c-6 shows significant nitrogen removal and was identified as Achromobacter oxylosoxidans subsp. oxylosoxidans with 16S rDNA sequence aliment.
The purpose set for future works is to estimate the improvement of nitrogen and COD removal from swine wastewater treatment by applying immobilized heterotrophic nitrifiers. Investigation of the efficiency and feasibility of simultaneously nitrification and denitrification of inoculated heterotrophic nitrifiers for swine wastewater treatment will also be carried out with appropriate techniques of molecular biology.
Subjects
同時硝化脫硝
廢水處裡
固定化
異營硝化
SND
wastewater treatment
immobilizaion
heterotrophic nitrificaion
Type
thesis
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