[Nitrite denitrification characteristics with redox mediator].

ABSTRACT

This study optimized the nitrite degradation conditions and explored the characteristics of nitrite degradation with redox mediators and nitrite denitrifying bacteria. The results suggested that the optimal condition of nitrite denitrification was 35 degrees C, pH = 8.0, sodium succinate as the carbon source, the C/N rate of 4 and the initial nitrite concentration of 100 mg x L(-1); the optimal AQS concentration was 0. 16 mmol x L(-1); ORP values stabilized around -400 mV to -500 mV with AQS, which were lower than that of controls during the denitrification process; the pH changed with nitrite removal and stabilized at 9 to 10; through the analysis of denitrifying intermediate metabolites, the impact of AQS on nitrite denitrifying process presumably not only played a coenzyme CoQ role but also accelerated the cytochrome transfer electronic process. This study provides the optimal parameters for practical application of the nitrite biodegradation with redox mediator.