游离氨和游离亚硝酸对亚硝态氮氧化菌活性的影响

Effect of FA and FNA on activity of nitrite-oxidising bacteria

高浓度游离氨(FA)或游离亚硝酸(FNA)条件下硝化过程常出现亚硝态氮积累,FA、FNA对亚硝态氮氧化菌(NOB)的影响并不清楚.首先用高浓度亚硝态氮污水富集培养NOB,对富含NOB的污泥进行荧光原位杂交技术(FISH)分析表明,Nitrobacter占细菌总数比例为(71±5)%.用此污泥考察不同FA、FNA浓度对NOB活性的影响.结果表明,NOB的活性随着FA浓度的增大逐渐减小,当FA浓度在10mgNH3-N/L左右时,NOB的活性仅为FA为0时的50%.低浓度的FNA(FNA<0.03mg HNO2-N/L)对NOB活性具有促进作用;当FNA≥0.2mg/L时,NOB的活性被完全抑制.采用Aiba模型计算得到FNA对NOB的抑制常数KI,FNA,NOB为0.0968mg/L.FNA在0.0968mg/L左右时NOB活性仅为FNA为0.003mg/L时的50%.

Nitrite accumulation always accompanies with the nitrification process under the conditions of high concentration of free ammonia （FA） or free nitrous acid （FNA）. The impact of FA and FNA concentration on nitrite-oxidising bacteria （NOB） was not clear. In this study, NOB activated sludge was enriched in a lab-scale SBR system with high concentration of nitrite nitrogen wastewater. The fluorescence in situ hybridization （FISH） analysis of NOB-rich sludge showed that Nitrobacter accounted for （71 ＆#177; 5）% of total bacteria. The effects of different FA, FNA concentrations on NOB activity were investigated using the sludge. Results showed that NOB activity decreased gradually with the increase of FA concentration. The NOB was still oxidizing nitrite at half of the maximum activity （FA=0mgNH3-N/L） at an FA concentration of 10mgNH3-N/L. Low FNA concentration （FNA＆lt;0.03 mg HNO2-N/L） was beneficial to enhance NOB activity and it was completely restrained when FNA≥ 0.2mg/L. The inhibition constant of FNA to NOB （KI,FNA,NOB ） was 0.0968mg/L with Aiba model. The activity of NOB decreased 50% as the FNA concentration increased from 0.003mg/L to 0.0968mg/L.