1. Toward N2O emission reduction in a single-stage CANON coupled with denitrification: Investigation on nitrite simultaneous production and consumption and nitrogen transformation.
- Author
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Yan, Peng, Li, Kai, Guo, Jin-Song, Zhu, Si-Xi, Wang, Zhi-Kang, and Fang, Fang
- Subjects
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DENITRIFICATION , *NITROGEN , *NITRITES , *ANAEROBIC bacteria , *BATCH reactors , *AMMONIUM - Abstract
A dynamic analysis approach for determining nitrite production and consumption rates was established to systematically investigate the characteristics of nitrogen transformation and N 2 O emission of the completely autotrophic nitrogen removal over nitrite (CANON) process coupled with denitrification using a sequencing batch biofilm reactor (SBBR). The results indicate that anaerobic ammonium-oxidizing bacteria was not inhibited significantly by low C/N ratios. There were no obvious differences in the nitrite production rate, nitrite consumption rate or nitrogen removal among reactors operated with C/N ratios of 0, 0.67 and 1.00, which suggested that the certain carbon source did not significantly affect the nitrite conversion and nitrogen removal in the process. More than 60% of total N 2 O emission is generated during the initial phase of each period in the SBBR. More than 94.5% of N 2 O was generated by NO 2 −-N consumption via denitrification in the process. Interestingly, total N 2 O production drops by 16.7%, when the C/N ratio increases from 0 to 1. This phenomenon may be caused by the inhibition of N 2 O production via AOB denitrification. Therefore, an appropriate carbon source (C/N = 1.00) has the beneficial effect of reducing N 2 O emission by CANON coupled with denitrification. The results of this study provide an important empirical foundation for the mitigation of N 2 O emission in the CANON process coupled with denitrification. Image 1 • N conversion and N 2 O emission were investigated in a CANON coupled with DN process. • AOB and AnAOB were not inhibited significantly by low C/N ratios. • Low C/N ratios did not evidently affect nitrite conversion and nitrogen removal. • More than 94.5% of N 2 O was generated by NO 2 −-N consumption via denitrification. • The C/N ratio should be maintained at 1.00 for the N 2 O emission reduction. [ABSTRACT FROM AUTHOR]
- Published
- 2019
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