Kinetic characteristics of immobilized denitrification granules under different initial pH
ZENG Jin-ping1, CHEN Guang-hui2, LI Jun1, DENG Hai-liang1, WANG Xiu-jie1
1. Key Laboratory of Beijing for Water Quality Science & Water Environment Recovery Engineering, College of Architecture and Civil Engineering, Beijing University of Technology, Beijing 100124, China; 2. College of Environmental Science and Engineering, Qingdao University, Qingdao 266071, China
Abstract：The rule of NO2--N、NO3--N、TN and pH during denitrification process was studied by using different initial pH in a bath-scale sequencing batch reactor with synthetic wastewater. The kinetic characteristics of immobilized granules also were investigated by batch tests. Under the condition of temperature 30℃,C/N 6and HRT 5h, the immobilized denitrification granules showed good performance during two weeks. Under the different initial pH, the nitrate removal occurs mainly in the 0~1h, and the nitrite accumulation attain its maximum at 1h, meanwhile the pH attained its maximum then slightly reduced, formed a breakpoint of pH curve. Therefore, the breakpoint of pH curve could be used as an indicator to show the maximum accumulation of nitrite. Kinetics study showed the maximum specific denitrification rate occurred at pH=8.0, the pH=7.5was the next. It showed the most suitable denitrifying pH range was 7.5~8.0, and the removal of TN was 91.74%. Compared with nitrate and nitrite specific denitrification rate, the reason for nitrite accumulation is that the reductive rate of nitrate was more than nitrite during denitrification process.
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