复合垂直流-水平流人工湿地系统除氮效果的影响因素

Influential factors of nitrogen removal efficiency by the integrated vertical-flow and horizontal-flow constructed wetlands

复合垂直流-水平流人工湿地系统对NH_4^+-N及TN去除效果的主要影响因素有水力负荷、溶解氧、植物、季节等。研究表明:复合人工湿地系统在1.2、0.8和0.4 m^3/(m^2·d)(高、中、低)3个水力负荷条件下对TN的平均去除率分别为58.28%、61.71%和63.94%,对NH_4^+-N的平均去除率分别为71.71%、59.74%和68.37%;有无充足的氧气对系统中NH_4^+-N和TN的去除效果影响较大,NH_4^+-N去除率从40%~50%提升到80%,TN的去除率从30%提升到70%;有植物的系统对NH_4^+-N及TN的去除率要比无植物的高3%~4%,二者差异不明显(P>0.05);夏秋季节系统对NH_4^+-N的去除率要高于春冬季节,二者具有明显差异(P<0.05),且不同停留时间条件下变化规律基本一致,夏季系统对TN的去除率最高,达86.62%,春季系统对TN的去除率最低,为30%~40%,二者相比有明显差异(P<0.05);温度和氧气是系统去除生活污水中TN和NH_4^+-N最主要的限制因子。

Influential factors of ammonia nitrogen（ NH4＋-N） and total nitrogen（ TN） removal efficiency by the integrated vertical-horizontal flow wetlands mainly include hydraulic loading rate,dissolved oxygen,plant and season,etc. The research results showed that the removal efficiency of TN and NH4＋-N by the constructed wetland under high,mid and low-loads hydraulic loading rate were 58. 28%,61. 71%,63. 94%,and 71. 71%,59. 74%,68. 37%,respectively. Removal efficiency of NH4＋-N and TN under well-oxygenated conditions were obviously improved from 40%-50% to 80% and 30% to 70%,respectively. Despite the 3%-4% higher removal of NH4＋-N and TN from the influent sewage in the system vegetated with plants,no significant differences in performance were observed between units with or without plants（ P 〉 0. 05）. NH4＋-N removal efficiency in summer and autumn was significantly higher than spring and winter at different retention time（ P 〈 0. 05）. TN removal efficiency in the wetland system was also remarkably different in different seasons（ P 〈 0. 05）,which reached the highest value in summer（ 86. 62%） and the lowest value in spring（ about 30%-40%）. The temperature and dissolved oxygen were the most important limiting factors for NH4＋-N and TN removal in the integrated vertical-horizontal flow constructed wetland.