| Title |
Denitrification Performance and Bacterial Community Structure of Methanol and Mixed Carbon Sources |
| Authors |
박수인 ( Suin Park ) ; 전준범 ( Junbeom Jeon ) ; 최민규 ( Minkyu Choi ) ; 김성진 ( Sungjin Kim ) ; 이상헌 ( Sanghun Lee ) ; 이태호 ( Taeho Lee ) ; 정상현 ( Sanghyun Jeong ) ; 배효관 ( Hyokwan Bae ) |
| DOI |
https://doi.org/10.15681/KSWE.2023.39.1.61 |
| Keywords |
Bacterial community structure; Denitrification; Granule; Methanol; Mixed carbon sources; Settleability |
| Abstract |
Denitrifying bacteria convert nitrate to nitrogen gas using an external carbon source as an electron donor. The external carbon source affects the denitrification performance and bacterial community structure. Although methanol is a cheap and effective external carbon source, the addition of diverse carbon sources may improve the total nitrogen removal rate and biomass characteristics, such as settleability. In this study, denitrifying reactions were performed using solely methanol and mixed carbon sources of methanol, glucose, and acetate in a sequencing batch reactor. The denitrifying reactor using methanol resulted in a total nitrogen removal rate of 0.39 ± 0.025 kg-N/㎥-day while the suspended biomass transformed into dark brown granules. Methyloversatilis discipulorum had the highest predominance at 43.84%. The individual denitrifying biomasses, which were separately enriched with methanol, glucose, and acetate, showed the same total nitrogen removal performance of 0.39 ± 0.016 kg-N/㎥-day. However, the addition of mixed carbon sources showed an improved total nitrogen removal rate of 0.42 ± 0.043 kg-N/㎥-day, with the domination of Candidatus Saccaribacteria at 25.61%. The denitrifying granules turned pale yellow color. Influent COD/NO₃ --N ratios of 3.5, 5, and 7.5 exhibited COD/NO₃ --N consumptions of 4.3 ± 0.4, 4.4 ± 0.8, and 5.2 ± 0.7, and the consistent predominance of Candidatus Saccharibacteria. |