氨氮对AOB抑制的形态及规律

Inhibiting Form of Ammonium to AOB and Inhibiting Rule

采用亚硝化生物膜反应器通过大量的批式实验,研究了氨氮对AOB抑制的形态及规律,控制反应条件为温度30℃,HRT 4.76 h,ORP 100 m V.结果表明,在进水氨氮浓度2 000 mg·L-1时,当AOB活性达到半抑制水平后,通过降低p H使FA浓度从235 mg·L-1降到13 mg·L-1,AOB的抑制得以解除.说明是FA对AOB产生抑制.将在各浓度梯度下得到的半抑制FA浓度IC50FA和达到半抑制水平所需反应时间t进行拟合,发现两者呈指数关系.通过分析具体方程发现在本实验条件下FA抑制AOB的最小值为98.84 mg·L-1.FA对AOB的抑制受FA浓度和反应时间两者的影响,且存在可以对AOB产生抑制的最小FA浓度值.当FA浓度大于该最小值且经过相应的反应时间后将会对AOB产生抑制作用.高浓度FA经过较短的反应时间即可对AOB形成抑制,较低浓度的FA经过足够长的反应时间可以对AOB形成与之相同的抑制水平.

The inhibiting form and rule of ammonium to ammonia oxidation bacteria( AOB) were investigated through a series of batch experiments using biofilm reactor,in which the reaction conditions were controlled to 30℃,HRT 4. 76 h,ORP 100 m V. The results showed that when the AOB activity was half-inhibited at an ammonia nitrogen concentration of 2 000 mg·L- 1,the concentration of FA was decreased from 235 mg·L- 1to 13 mg·L- 1by reducing p H,leading to the removal of the AOB inhibition. This indicated that FA was the real inhibitor for AOB. The half inhibitory concentration of FA and reaction time required to reach this concentration obtained from the concentration gradient test were fitted. The results confirmed that there was an exponential relationship between them. The inhibitory threshold value of FA to AOB was 98. 84 mg·L- 1under the experimental condition. Both the concentration of FA and the reaction time had a great influence on the inhibition of FA to AOB,and there was a minimal FA concentration that could cause inhibition to AOB. When the concentration of FA was greater than this threshold value,the activity of AOB would be inhibited after a suitable reaction time. High concentration of FA could inhibit AOB within a short time,so could low concentration of FA after an enough long reaction time.