盐度对SBR处理低碳氮比废水脱氮性能的影响

采用基于厌氧-好氧-缺氧(AOA)流程的序批式活性污泥法反应器(SBR),研究了NaCl盐度对活性污泥系统处理低碳氮比废水(COD/ρ(TN)=5)脱氮过程的影响。结果表明,当盐度(NaCl的质量分数)达到2%时,COD、TN仍有较高的去除效果,COD和TN的去除率分别为97.74%和99.16%。当盐度达到3%时,COD的去除率变化不大(97.84%),但TN的去除率受到影响,其去除率降至82.06%。通过米-门方程对硝化过程NH^+4-N的质量浓度和反硝化过程NO^-2-N的质量浓度变化进行拟合,得到了在盐度0、1%、2%、3%下的最大比降解速率和半饱和常数。当盐度在1%~3%时,活性污泥系统发生了持续且稳定的短程消化反硝化过程;高盐度对硝化细菌的影响是导致出水TN含量升高的主要因素。

Effects of Salinity on Nitrogen Removal Performance of SBR for Low C/N Wastewater Treatment

The effects of Na Cl salinity on nitrogen removal process of activated sludge system treating low carbon/nitrogen(C/N) wastewater(COD/ρ(TN)=5) were investigated in an alternating anaerobic/oxic/anoxic(AOA) sequencing batch reactor(SBR). The results showed that, when the salinity(NaCl mass fraction) reached 2%, the system still kept advanced COD and TN removal with a high removal efficiency of 97.74% and 99.16%, respectively. When the salinity reached 3%, the removal rate of COD was less affected(97.84%), but the removal rate of TN was more affected and decreased to 82.06%.The mass concentration of NH^+4-N in nitrification process and the mass concentration of NO^-2-N in denitrification process were fitted by Michaelis-Menten model, the maximum specific degradation rate and the half saturation coefficient were obtained with salinity of 0, 1%, 2% and 3%. Stable and persistence shortcut nitrification-denitrification process was established under the condition of salinity was 1%~3%. The effect of high salinity on nitrifying bacteria is the main factor leading to an increase of TN content in effluent.