低温对硫自养反硝化脱氮系统的影响及调控措施

为了提高低温下硫自养反硝化系统的脱氮性能,通过改变电子供体(硫源),并结合异养反硝化作用,利用序批试验,比较了不同温度下反应系统的脱氮性能。试验结果表明,低温条件下硫自养反硝化脱氮作用受到明显的抑制,5℃时硝态氮的还原反应速率常数为0. 003 7 mg^0.5/(L^0.5·h),仅为25℃时的3. 2%,并且亚硝态氮积累严重,p H值降低明显。相较于单质硫,低温条件下投加硫代硫酸盐或乙酸盐后,系统的反应速率常数分别提升2. 81倍和8. 49倍。加入乙酸盐能够有效缓解亚硝态氮的积累,5℃时亚硝态氮的还原反应速率常数为0. 200 0 mg^0.5/(L^0.5·h),而加入单质硫或硫代硫酸盐试验组的亚硝态氮浓度没有明显下降。

Effect of Low Temperature on Sulfur Autotrophic Denitrification and Its Improvement

The denitrification performance of the reaction system at different temperatures was compared by changing the electron donor ( sulfur source ) and combining with the heterotrophic denitrification through batch experiments, in order to improve denitrification performance of the sulfur autotrophic denitrification system at low temperature. The results showed that the effect of sulfur autotrophic denitrification was significantly inhibited at low temperature. The half-reaction rate constant of nitrate removal was 0. 003 7 mg°5/( L^0.5·h) at 5 ℃,which was equal to 3. 2% of the half-reaction rate constant at 25℃. Meanwhile, the nitrite nitrogen accumulated greatly and the pH dropped quickly under low temperature. The denitrification rate was increased by 2. 81 times and 8. 49 times respectively when the thiosulfate and acetate were added under low temperatures, compared with that of elemental sulfur. Aciding acetate also helped to reduce the accumulation of nitrite nitrogen, and the half-reaction rate constant of nitrite nitrogen removal was increased to 0. 200 0 mg^0.5 /(L^0.5·h) at 5 ℃. However, there was no significant decrease of nitrite nitrogen with the addition of elemental sulfur or thiosulfate.