Study On Kinetics Of Degrading Pyridine Under Anoxic Conditions And Process Controlling Factors

This thesis particularly focused on the kinetics of denitrification degrading pyridine under anoxic conditions. Batch experiments were carried out to study the variation of nitrate, nitrite, and pyridine during the process of denitrification. Frist, based on the double substrate Monod equation, the kinetic equations were established, and the kinetic parameters were estimated. Then the accumulation mechanism of intermediates in denitrification was studied. Finally the change rule of pH and ORP in denitrification was analyzed. Conclusions from the results of the experiments could be summarized as follows: When electron acceptor was nitrate and electron sponsor was pyridine, the denitrification kinetics could be described by the double substrateMonod equation, q = , in which K_s ≈ 4mg/L, K_NO3≈ 1 mg/L,q_mS ≈ 0.0011 min^-1 , q_mNO3 ≈ 0.0012 min^-1;When electron acceptor was nitrite and electron sponsor was pyridine, the denitrification kinetics could be characterized bythe double substrate Monod equation, q = , in which K_s ≈5mg/L, K_NO2 ≈ 1mg/L, q_mS ≈ 0.0011 min^-1, q_mNO2 ≈ 0.0008 min^-1;Usually, whenelectron acceptor was nitrite or nitrate and electron sponsor was pyridine, C/N had almost no effects on the velocity of denitrification;The accumulation mechanism of nitrite in denitrification was affected by C/N, temperature, and pH. pH features most among these contributing factors. The more pH was becoming, the higher the accumulation extent of nitrite was going;When carbon source was not abundant, accumulation of N₂O would happen. If pH is less than 6, although carbon source was abundant, accumulation of N₂O would also occur;The change of pH and ORP were closely correlated with the denitrification process. The change of pH and ORP could be used to define the proceeding of the denitrification process.