潜流人工湿地中基质在污水净化中的作用机制与选择原理

潜流人工湿地依靠基质、微生物以及植物的共同作用实现对污水中各类污染物的去除。其中，基质是潜流人工湿地的重要组成部分，在水质净化中发挥着至关重要的作用。基质可对污染物进行直接吸附去除。不同基质类型对氨氮与总磷具有不同的吸附能力，同时，吸附效率受到水质、水力条件等参数影响。此外，基质为微生物提供附着表面，基质材质、内部孔道结构、比表面积等均影响生物膜的形成与发展，进而间接影响人工湿地的污水净化功能。通过改变基质所处淹没/暴露状态、增加缓释碳源基质、增加铁碳电解对基质等方式来增加补氧、强化反硝化和电化学强化，从而改善人工湿地对NH₃-N、TN与TP类污染物的去除效果。

ROLE AND DESIGN PRINCIPLES OF SUBSTRATE FOR WASEWATER PURIFICATION IN SUBSURFACE FLOW CONSTRUCTED WETLAND

The wastewater purification in subsurface flow constructed wetland is realized by the combined functions of substrate, microbes, and plant. Substrate, as an important element, plays critical role in wastewater purification. Firstly, substrate could directly absorb pollutants. The efficiency of pollutant absorbance varies with the substrate material, which is also influenced by the water quality, hydraulic condition, etc. Secondly, substrate could provide the surface for microbes to form biofilm. The properties of substrate, e.g. the material, the saturated/unsaturated condition of substrate, the inner porous structure, and specific surface area, all affect the formation and development of biofilm, as well as the wastewater purification indirectly. Increasing the unsaturated area of substrate, adding the material that could slow-release carbon source, adding Fe-C micro-electrolysis material could improve the removal of ammonia, total nitrogen, and phosphorus by enhancing the oxygen supplement, denitrification process and the chemical sedimentation process, respectively.