人工沉床对TN的去除效果及其影响因素

Study on removal efficiency and influence factors of TN for constructed submerged hydrophyte bed

建立一种模块化气浮调节式人工沉床,并应用于重富营养化水体的生态修复,在天津市外环河进行现场试验。结果表明：当停留时间为5.48 d时,人工沉床对TN的去除率在植物生长期内（3—10月）可达到35%-40%;冬季（11月至次年2月）可达到5%-15%。TN浓度随停留时间的变化符合一级动力学方程,相关系数R^2均在0.9以上。衰减系数随水温的变化趋势符合S形增长曲线,即在水温过低和水温过高时,水温的变化对衰减系数的影响并不大,但在某一适当温度范围内,水温的上升将导致衰减系数的快速增加。

A kind of modularized and air-adjustable constructed submerged plant bed（CSPB）,which can be used to restore eutrophic water,is introduced.This plant bed overcame the restriction of harmful factors such as blurred water transparency,frequently changing water depth,algal bloom,and duckweed rampant in summer;helped hydrophytes to grow;and enhanced the survival rate in the eutrophic water.The pilot study in the Waihuan River of Tianjin revealed that the reduction of total nitrogen（TN） could reach 35% to 40% in the growing season（from March to October） and 5% to 15% in winter（from November to the following February） when the detention time was 5.48 days.In the pilot fields,the relations between the concentration of TN and the detention time fit the first-order kinetic equation,and the correlation coefficients（R2） were above 0.9.The attenuation coefficients K of the kinetic equation changed with the water temperature as follows： when the water temperature was too low or too high,the value of K did not significantly change with the temperature of water,but the increase of water temperature would lead to a rapid increase in the K value when the temperature was in a suitably moderate range.