腐殖酸预处理对活性污泥中硝化菌活性的影响

Effect of pre-treatment with humic acids on the activity of nitrifying bacteria in activated sludge

摘要:

为考察腐殖酸(HA)预处理对硝化菌——氨氧化菌(AOB)和亚硝酸盐氧化菌(NOB)活性的影响, 将不同质量浓度梯度的腐殖酸(HA)分别投加到全程硝化污泥Sc₁(硝化活性较低)和Sc₂(硝化活性较高)以及短程硝化污泥Sp(硝化活性较高), 预处理24 h, 每种污泥均采用相同的HA质量浓度梯度(0、80、160、240 mg/L)处理.结果表明, 当采用80 mg/L(50 mg/g MLVSS)的HA预处理后, 污泥Sc₁的NOB活性就有了显著提高, 硝化反应过程中的硝态氮积累率(R_NA)由不投加HA预处理时的26.32%增加至78.82%, 而氨氧化速率(R_AO)没有显著变化, 表明HA预处理对AOB的活性没有影响而提高了NOB的活性.对于污泥Sc₂, 投加不同质量浓度的HA预处理既没有改变R_AO也没有影响R_NA, 这说明对于活性较好的AOB和NOB, HA预处理并没有进一步提高其活性, 同时也不会抑制其活性.对于污泥Sp, HA的预处理没有破坏其短程效果, 基本没有NO₃^--N的积累.因此, HA预处理对于AOB活性基本没有影响, 但是影响了NOB的活性, 在其活性不高时, 能提高其活性, 在其活性高时, 既不会被进一步提高也不会被抑制.

Abstract:

The aim of the present study was to investigate the effect of pre-treatment with humic acids on the activity of nitrifying bacteria (ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB)) in activated sludge processes. Varied concentration of HA (0, 80, 160, 240 mg/L) were applied to pretreat (24 h) three different sludges, including complete nitrification activated sludge with low/high activity (Sc₁/Sc₂), and the partial nitrification activated sludge (Sp). The results showed that the nitrate accumulation rate (R_NA) of Sc₁ increased significantly from 10.73 % to 53.93% after pretreatment with 80 mg/L of HA (50 mg/gMLVSS), simultaneously the ammonia oxidation rates (R_AO) changed insignificantly. In terms of Sc₂, neither the R_AO nor the R_NA changed under each tested condition. For Sp, no NO₃^--N accumulation was observed after the pretrement, which demonstrated that the HA pretreatment did not destruct its partial nitrification performance. In conclusion, HA pretreatment improved the activity of NOB which with low overall nitrification activity, while exhibited insignificant improvement on AOB activity.