人工湿地脱氮途径及其影响因素分析

Analyse of nitrogen removal pathways and their effect factors in constructed wetland

简述了人工湿地脱氮模型。各种形态的氮在人工湿地系统中可以通过氨的挥发、植物吸收、介质沉淀吸附以及微生物硝化/反硝化作用等过程被去除。讨论了各脱氮途径对人工湿地脱氮的贡献,在大多数人工湿地的pH条件下,湿地地面氨挥发可以忽略,湿地植物叶片氨挥发量尚不清楚。湿地介质的直接吸附是短期的。植物在湿地脱氮过程中起了重要作用,但一般认为植物直接吸收和存储只占湿地脱氮的一小部分,一般低于30%。微生物的硝化/反硝化作用,是人工湿地脱氮的最主要的形式。讨论了影响人工湿地硝化作用的主要因素:溶解氧,pH和温度。大多数人工湿地的pH适合硝化作用,溶解氧和温度对湿地硝化作用的影响最大。温度不仅影响微生物的硝化作用,而且可以间接地影响植物的生长从而影响人工湿地的脱氮性能。

Nitrogen removal model from wastewater in constructed wetlands （CW） was simply described. Nitrogen could be removed in constructed wetland through processes including NH3 volatilization, plants uptake, matrix sedimentation and nitrification-denitrification of microorganism, The role of each process for nitrogen removal was evaluated. Under the pH conditions in most constructed wetlands, ammonia volatilization by wetland surface could be neglectable, while ammonia volatilization by plant leaves is still unknowable. Adsorption by matrix is short-term. Plants play important role in nitrogen removal in CW. However, plant uptake accounts for a small proportion of generally bellow 30% of total nitrogen removed. Consequently, uptake by plants is not significant. Nitrogen losses through nitrification-denitrification are generally the most significant N-removal mechanisms for WC. Three important factors that influence nitrification rates were discussed, dissolved oxygen （DO）, pH and temperature, pH conditions in Most CWs are suitable for nitrification. DO and temperature are the mostly important factors influence nitrification in CW. Temperature is not only influence nitrification of microorganisms, but indirectly influence CW performance of nitrogen removal through plants growth.