浮萍塘中氮归趋模式模拟分析

通过模拟分析浮萍塘中氮的循环迁移过程,考察了N主要迁移途径对各形态氮的去除贡献,并确定了水环境季节变化对氮循环过程影响.模拟结果显示:浮萍塘中氮的去除主要通过硝化/反硝化作用实现,而有机氮沉降以及氨氮挥发作用对TN去除贡献仅为2.1%.浮萍塘中氨氮和硝态氮的变化主要受硝化和反硝化作用影响;有机氮主要受藻类腐败以及氨化作用影响;底泥中氮的变化主要由有机氮沉降和底泥中氮氨化过程控制.此外,浮萍塘能有效去除水体中藻类,并维持藻类的较低含量;浮萍主要通过促进硝化/反硝化速率来提高系统对TN的去除能力.

Study on Nitrogen Cycling and Transformations in a Duckweed Pond by Means of Modeling Analysis

Based on the simulated results from N cycling and transformation model of duckweed pond,the influences of different major transfer pathways on various nitrogen removal performances are investigated.The effects of seasonal variations of water conditions on nitrogen transformations are determined.The simulated results show that nitrification and denitrification were the major removal pathways for nitrogen in duckweed pond,and the removal contributions of organic nitrogen sedimentation and ammonia volatilization for total nitrogen removal were less than 2.1%.Furthermore,in duckweed pond,nitrification and denitrification decided the removal efficiencies of ammonia and NO_x,respectively;both algae decaying and organic nitrogen ammonification controlled primarily the organic nitrogen removal performances;both organic nitrogen sedimentation and mineralization of sedimentary nitrogen determined the variations of sedimentary nitrogen.Duckweed pond with duckweed growing largely can increase sharply algae mortality and keep the low content of algae in effluent.Besides,through accelerating the nitrification and denitrification rate,duckweed can evidently improve the removal efficiencies of total nitrogen.