游离亚硝酸对高效硝化菌的抑制影响

Effect of Free Nitrous Acid Inhibition on High-efficiency Nitrifying Bacteria

为了考察游离亚硝酸(free nitrous acid,FNA)对高效硝化菌(氨氧化菌(ammonia-oxidizing bacteria,AOB)和亚硝酸盐氧化菌(nitrite-oxidizing bacteria,NOB)活性的抑制影响.采用连续流反应器,通过逐步提高氨氮质量浓度的方式富集培养高效硝化菌,使得硝化速率高达89mg/(L h),通过对污泥富集培养前后细菌群落组成的高通量分析表明,Nitrosomonas(31.02%)比原污泥提高了72.13倍,而Nitrospira(4.36%)提高了2.03倍.用富集培养后的污泥考察不同 FNA 质量浓度对 AOB 和 NOB 活性的影响,并通过探究得出的有效 FNA 质量浓度作用于不同硝化速率的污泥,考察在实现高纯度的高效 AOB 菌群培养过程中,FNA 值域的控制.结果表明,AOB 和 NOB 的活性均受到FNA的影响,当FNA的质量浓度为0.5和0.6mg/L时,AOB和NOB均保持较高活性.当FNA的质量浓度为0.7mg/L时,不仅能使NOB活性逐渐降低到0,而且能使AOB活性保持在56%以上.当FNA的质量浓度为0.9mg/L时,AOB活性受到严重的抑制.因此,在实现高纯度的高效AOB菌群培养的过程中,0.7mg/L是FNA最适宜的质量浓度,并且对15~89mg/(L h)的硝化速率的污泥仍然有效,但随着硝化速率的提高,FNA的质量浓度也需要相应提高以抑制 NOB 活性同时保留 AOB 活性.

To investigate the effect of free nitrous acid (FNA) inhibition on the activity of high-efficiency nitrifying bacteria ( ammonia-oxidizing bacteria ( AOB) and nitrite-oxidizing bacteria ( NOB)), a continuous-flow reactor was conducted at ammonia concentration gradients (50 mg/ L→80 mg/ L→100 mg/ L→150 mg/ L→200 mg/ L→250 mg/ L→300 mg/ L→350 mg/ L→400 mg/ L→450 mg/ L), resulting in a high nitrification rate of 89 mg/( L·h). High-throughput analysis showed that Nitrosomonas (31.02%) increased by 72.13 times compared with the raw sludge. At the same time, Nitrospira (4.36%) increased by 2.03 times. The effects of different FNA concentrations on AOB and NOB activity were investigated by using the sludge. Subsequently, the effective FNA concentration obtained was applied for sludge with different nitrification rates. Results show that FNA inhibition can dramatically inhibit AOB and NOB activity. When the FNA concentration maintains at 0.5 or 0.6 mg/ L, high activity happens in AOB and NOB. The NOB activity is gradually reduced to 0% and AOB activity still maintains above 56% at an FNA concentration of 0.7 mg/ L. The AOB activity is severely inhibited at an FNA level of 0.9 mg/ L. Therefore, the FNA concentration of 0.7 mg/ L can significantly inhibit NOB activity when the nitrification rates are between 15 and 89 mg/(L·h). However, FNA values should be increased to inhibit NOB activity and retain AOB activity as the nitrification rate increases.