悬浮载体生物膜上苯酚的硝化抑制研究

Study of phenol inhibition to the nitrification process on the suspended carrier biofilm

采用悬浮载体序批式反应器,研究苯酚对硝化反应的抑制作用和温度、pH对抑制作用的影响.苯酚的启始质量浓度分别为0 mg/L,2 mg/L,5 mg/L,10 mg/L,15 mg/L和20 mg/L,研究表明,质量浓度越大,抑制作用越强.苯酚对硝化作用的抑制为可逆的、非竞争性抑制.微生物对苯酚有降解作用,当启始质量浓度不高于10 mg/L时,苯酚降解后,硝化活性可以完全恢复.悬浮载体生物膜比活性污泥具有更强的毒性忍耐能力.温度变化对苯酚的硝化抑制作用影响较大.温度升高,苯酚的降解加快,抑制时间缩短;同时,温度的增加也有利于提高硝化反应的速率.当pH减少时,苯酚的降解速度加快,硝化反应受到抑制的时间变短,但是较低的pH会导致硝化速率降低,在试验条件下,pH在7.5左右较为合适.

The effect of phenol on the nitrifying activity of suspended cartier biofilm was studied in batch assays. Phenol was supplemented to reactors at initial concentration of 0,2,5,10,15 and 20 mg/L,respectively. Phenol was inhibitory to the nitrification process, showing more inhibition at higher initial phenol concentrations. The nitrification inhibition of phenol was non-competitive and reversible. When initial phenol concentrations were not higher than 10 mg/L, nitrifying activity was recovered completely after degradation of phenol. The results indicated that nitrifying bacteria embedded in the suspended carrier biofilm might have a better ability to withstand the shock of phenolic compound in wastewater than suspended nitrifying bacteria. Nitrification rate was more sensitive to temperature change in phenol - contained wastewater. When temperature increased, the biodegradation rate of phenol increased, and the nitrification inhibition time of phenol was shortened. At the same time, the nitrification rate increased. With the value of pH decreasing, the biodegradation rate of phenol increased, which made the time of nitrification inhibition shortened. But due to the lower pH value resulting in the decrease of nitrification rate, the optimal pH value in assays was about 7.5.