无机废水中好氧颗粒污泥脱氮及钇吸附性能研究

Performance of aerobic granular sludge for nitrogen removal and yttrium adsorption from inorganic wastewater

以好氧颗粒污泥(AGS)处理无机高氨氮废水脱氮性能及对钇离子(Y(Ⅲ))吸附效果为研究对象,探索了“好氧+缺氧”模式下自养硝化颗粒污泥(ANGS)的脱氮性能及“好氧+缺氧+好氧”模式下AGS的脱氮性能及短期钇离子冲击下系统稳定性,利用热力学、动力学模型等研究了AGS对Y (Ⅲ)的吸附能力和机理。结果表明,“好氧+缺氧”模式导致混合液悬浮物固体浓度(MLSS)及平均粒径持续减小,通过降低进水氮负荷并补充ANGS使氨氮去除率逐渐增大(3.25%~73.51%);采用“好氧+缺氧+好氧”运行模式并补充AGS后,氨氮去除率超过72.00%(50~72天),MLSS及平均粒径增大,总无机氮(TIN)含量基本保持不变。72天后投入碳源,氨氮去除率减小至40%以下、TIN去除率增大至30%左右。第78天起Y(Ⅲ)浓度在0.01~0.82 mg/L之间,去除率基本稳定在88%以上;通过改变曝气方式和外投碳源后,AGS内Nitrosomonas丰度明显下降(47.43%~11.08%),而Thauera、 unclassified_Chitinophagaceae、 unclassified_Comamonadacea、Comamonas等反硝化菌属的丰度呈现不同程度增大。通过X射线光电子能谱发现,钇以沉淀物或结晶形式存在于AGS中,AGS对Y(Ⅲ)的吸附符合Langmuir方程及伪二级动力学模型。

The performance of aerobic granular sludge(AGS) for nitrogen removal and yttrium ion adsorption fr om inorganic wastewater with high ammonia nitrogen was explored, to provide technical support for the efficient treatment of ionic rare earth mine wastewater. The denitrification performance of autotrophic nitrifying granular sludge(ANGS) under oxic/anoxic operation mode was first explored. Then, the denitrification performance of AGS under oxic/anoxic/oxic operation mode and the stability of AGS under short-term Y( Ⅲ)shock were investigated. Finally, the Y(Ⅲ) adsorption capacity and mechanism of AGS were explored by thermodynamic and kinetic models. The oxic/anoxic operation mode resulted in a continuous decrease in mixed liquor suspended solids(MLSS) and average particle size. However, the ammonia nitrogen removal efficiency gradually increased(3.25%~73.51%) by reducing the influent nitrogen load and supplementing ANGS. After changing into the oxic/anoxic/oxic operation mode and supplementing AGS, the removal efficiency of ammonia nitrogen remained above 72.00%(50~72 days), and the MLSS and average particle size gradually increased.Nevertheless, the removal of total inorganic nitrogen(TIN) has rarely been detected. After day 72, the removal efficiency of ammonia nitrogen decreased rapidly to below 40%, while the removal efficiency of TIN increased to approximately 30%. After day 78, the Y(Ⅲ) concentration in the effluent was between 0.01 and 0.82 mg/L,and its removal efficiency was above 88%. The change in the aeration mode and dosage of the external carbon source led to a significant decrease in the relative abundance of Nitrosomonas in the AGS(47.43%~11.08%).However, the relative abundance of denitrifying bacterial genera such as Thauera, unclassified_Chitinophagaceae,unclassified_Comamonadacea and Comamonas increased to varying degrees. X-ray photoelectron spectroscopy indicated that yttrium existed in AGS as precipitation or crystallization. The Y(Ⅲ) adsorption of AGS conformed to the Langmuir isotherm and pseudosecond-order kinetic model.