Improvement of autohydrogenotrophic nitrite reduction rate through optimization of pH and sodium bicarbonate dose in batch experiments(ENVIRONMENTAL BIOTECHNOLOGY)

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概要

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• Accumulation of nitrite intermediate in autohydrogenotrophic denitrification process has been a challenging difficulty to tackle. This study showed that further growth of "true denitrifying" bacteria and adaptation to nitrite led to a faster reduction of nitrite than nitrate as a solution to circumvent nitrite accumulation. Moreover, two effective parameters namely pH and bicarbonate dose were optimized in order to achieve a better reduction rate. Sodium bicarbonate dose ranging from 20 to 2000mg/L and pH in the range of 6.5-8.5 was selected to be examined employing 0.2g MLVSS/L of reacclimatized denitrifying bacteria. Eleven runs of experiments were designed considering the interactive effect of these two operative parameters. A fairly close reduction time less than 4.5h(>22.22mg NO_2^--N/g MLVSS/h) was gained for the pH range between 7 and 8. The highest specific nitrite reduction rate at 25mg NO_2^--N/g MLVSS/h was achieved applying 1000mg NaHCO_3/L at pH 7.5 and 8. The pH was found to be the leading parameter and bicarbonate as the less effective parameter on nitrite reduction removal. Central composite design(CCD) and response surface design(RSM) were employed to develop a model as well as define the optimum condition. Using the experimental data, the developed quadratic model predicted optimum condition at pH 7.8 and sodium bicarbonate dose 1070mg/L upon which denitrifiers managed to accomplish reduction within 3.5h and attained the specific degradation rate of 28.57mg NO_2^--N/g MLVSS/h.

著者

• Ghafari Shahin

  Department Of Chemical Engineering Faculty Of Engineering University Of Malaya

• Hasan Masitah

  Department of Chemical Engineering, Faculty of Engineering, University of Malaya

• Aroua Mohamed

  Department of Chemical Engineering, Faculty of Engineering, University of Malaya

• Hasan Masitah

  Department Of Chemical Engineering Faculty Of Engineering University Of Malaya

• Aroua Mohamed

  Department Of Chemical Engineering Faculty Of Engineering University Of Malaya

関連論文

• Improvement of autohydrogenotrophic nitrite reduction rate through optimization of pH and sodium bicarbonate dose in batch experiments(ENVIRONMENTAL BIOTECHNOLOGY)

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