[Cometabolic biodegradation of nitrogenous heterocyclic compounds indole and pyridine under anoxic conditions]

Based on the traditional theory of denitrification under anoxic conditions, and with the addition of nitrate, experiments were conducted to investigate the cometabolic biodegradation of nitrogenous heterocyclic compounds-indole and pyridine. Results show that the optimum ratio of COD to nitrate (C/N) is 8.4 to approximately 8.9. Under the conditions with temperature of 28 degrees C and pH of 7.0 to approximately 7.5, the nitrate reductase activity (NRA) is in the best state. Addition of pyridine can promote NRA and the degradation of indole. When the initial concentration of indole is 150 mg/L, the concentration ratio of indole to pyridine is 1 to approximately 10, and under the optimum C/N conditions, the degradation of indole meet with zero-order kinetics. There was no accumulation of nitrite during the reaction. When the concentration ratio of pyridine to indole is less than 0.25, with the increase of pyridine concentration, there is a faster augment rate for NRA and the degradation of indole than the situation when the concentration ratio of pyridine to indole is more than 0.25.