硝化过程中影响亚硝酸盐积累的因素

采用间歇式批试验法,改变pH值、DO浓度和温度,试验发现:当pH值分别为8.2、7.5、9.2、6.5和5.0,DO分别为1.0mg/L、2.0mg/L、4.5mg/L和温度为30℃、25℃、35℃和10℃时,氨氧化速率依次减小。进水氨氮浓度为50mg/L～250mg/L,保持pH值为8.0±0.2时,游离氨浓度为4.45mg/L～22.68mg/L左右,最大HNO2浓度远<0.2mg/L,游离氨和HNO2对好氧氨氧化菌的影响较小。结果表明,pH值、DO浓度和温度对好氧氨氧化菌的富集有显著影响。在富集过程中,控制pH值、DO浓度和温度是关键因素,游离氨和HNO2进行适当控制,以保证抑制亚硝酸盐氧化菌而不抑制好氧氨氧化菌。

Factors Affecting Nitrite Accumulation in Nitrification Process

The ammonium oxidation rate was studied through changing pH,DO and temperature in sequence batch experiments.Results showed that the ammonium oxidation rate decreased in turn when pH was at 8.2,7.5,9.2,6.5 and 5.0, DO was 1.0mg/L,2.0mg/L and 4.5mg/L,temperature was 30℃ ,25℃ ,35℃ and 10℃ respectively.The concentration of ammonia in the influent was 50～250mg/L,pH was 8.0±0.2,the highest of free ammonia(FA)and nitrous acid concentration were 4.45～22.68mg/L and less than 0.2mg/L respectively.FA and nitrous acid had little influence on the aerobic ammonia oxidation bacteria.Results indicated that pH,DO and temperature had significant influence on the enrichment of aerobic ammonia oxidation bacteria.During the enrichment cultivation,pH,DO and temperature were the key factors,and FA and nitrous acid could be properly controlled to inhibit the growth of nitrite oxidation bacteria,but not the ammonia oxidation bacteria.