初始pH值对废水反硝化脱氮的影响

为探讨pH值对硝态氮反硝化体系的影响，设定初始pH范围为4-10，对反硝化过程中NO3-N、NO2-N、TN、TOC和△TOC/△TN的变化规律、反硝化动力学以及抑制机理进行研究. 结果发现：最适宜的反硝化pH值为8，过酸过碱都不利于反硝化过程的进行. 在pH=8时，反应时间最短，硝态氮的去除率为99.4%，TN的降解率为95.5%. 亚硝态氮积累量在pH〈7时小于1 mg/L；pH〉7时，随pH的增大而增大，最大积累率为22%. 硝态氮比反硝化速率在pH=8时最大，为2.52 mg NOx-N/（g MLVSS·h）；亚硝态氮比反硝化速率在pH=7时最大，为1.66 mg NOx-N/（g MLVSS·h）. 因此，反硝化最佳的pH值为7～8.

The Impacts of Initial pH on Wastewater Denitrification

In order to study the impacts of different initial pH on nitrate denitrification system,the paper set the initial pH value from 4to 10,and studied the change rules of NO-3-N,NO-2-N,TN,TOC and△TOC/△TN in the denitrification process,denitrification dynamics and inhibiting mechanism of denitrification.It was found that the most optimal denitrifying condition was pH=8.The value of pH was not conducive to the denitrification process,if it was bigger or smaller.When pH=8,the reaction time was the shortest,the nitrate removal rate was 99.4% and the maximum degradation rate of TN was 95.5%.The accumulation of nitrite was less than 1 mg/L when pH7,when pH7,the nitrite accumulation rate increased with the increase of pH,the greatest accumulation rate was 22%.The maximum special denitrification rate of nitrate was 2.52（mg NO-x-N）/（g MLVSS·h）when pH=8,while the maximum special denitrification rate of nitrite was1.66（mg NO-x-N）/（g MLVSS·h）when pH=7.Therefore,the optimum pH of denitrification was 7-8.