Analysis of Nitrite Accumulation During Denitrification
GE Shi-jian,WANG Shu-ying,YANG An-ming,PENG Yong-zhen,GAN Yi-pin and CAO Xu
DOI:10.11835/j.issn.1674-4764.2011.01.024
Received June 20, 2010,Revised , Accepted , Available online July 01, 2015
Volume ,2011,Pages 140-146
- Abstract
To realize the purpose of enhanced nitrogen removal (TN<5 mg·L-1) in step feed process treating urban wastewater, by using SBR reactor, the nitrite accumulation, variation of pH and ORP as well as dynamic properties during denitrification with methanol and glucose as the sole carbon sources are investigated in details. The results show that for both carbon sources, serious nitrite accumulations are observed during denitrification under different ratios of nitrogen and carbon (C/N). With identical C/N, when glucose is used as carbon source there is more maximum NO2--N accumulation concentration. However, NO3--N reduction rate is faster than NO2--N reduction rate for both carbon sources. Furthermore, with the increase of C/N, the maximum NO2--N concentration increases and the time in which the NO2--N achieves the highest concentration is accordingly shortened. For glucose, however, under high C/N ratio (C/N=29.3) both the denitrification rate and NO2--N accumulation concentration decrease. Besides, the changes of pH and ORP reflect the variation of NO2--N accumulation concentration well because pH and ORP have the significant relationship with NO2--N concentration. The second inflexion on curves indicates the real end of denitrification process.