潜流园林人工湿地脱氮除磷效果正交试验

Efficiency of Nitrogen and Phosphorus Removal in Subsurface Flow Garden Constructed Wetland Based on Orthogonal Design

以柳树、湿地填料构建潜流型园林人工湿地,考察其脱氮除磷效果,为优化滤池结构,及其应用推广确定最佳运行条件。通过设计L9(34)正交试验,研究了填料、填料铺装方式、植物和水力停留时间(HRT)4个因素对考察指标的影响显著性及优选条件。运用SPSS19.0软件对试验数据的极差、回归分析表明,填料、填料铺装方式、植物、水力停留时间与潜流式园林人工湿地氮、磷去除率间呈显著的线性相关关系,相关系数R2分别为0.996、0.967;各因素对总氮去除率的影响程度排序为:填料、水力停留时间、填料铺装方式、植物;对总磷去除率的影响程度排序为:填料、填料铺装方式、水力停留时间、植物;潜流型园林人工湿地总氮去除率最高的操作条件为:陶粒和页岩的组合均匀混合铺装,种植馒头柳,HRT为9 d,TN去除率预测值为81%;有利于总磷去除率的最佳操作条件为:陶粒和页岩异垂直分层方式填装,植物为旱柳,HRT为6 d,TP去除率预测值为78.2%。

Sub-surface flow garden constructed wetlands were constructed with willows and wetland substrates to investigate the efficiency on TN and TP removal, in order to supply the theoretical basis for their applying. Orthogonal experiment was designed to investigate the significance and optimal conditions of four factors such as substrates, loading way, garden trees and hydraulic resident times （HRT） on the study index. Software SPSS19.0 was used to make range analysis and regression analysis of results of the orthogonal experiment. The results show that there is evident line correlation between TN, TP removal rate and substrates, loading way, garden trees and HRT in subsurface flow garden wetland. The factors having notable influence on TN removal are in the order as substrate. HRT, tilling way, garden tree, with a coefficient of determination of 0.996. The influence degree of the four factors on TP removal from larger to lower is as substrate, tilling way, HRT, garden tree. When salix matsudanas were planted as wetland plants, the optimal condition for best removal of TN is with the even mixture of ceramsite and shale as substrate of the garden wetland, HRT of 9 days, in which prediction rate of TN removal is 81%. The optimal combination advantageous to TP removal rate are the perpendicular loading with the lay of ceramsite and shale, plants for dryland willow steamed bread, HRT for 6 days, and the projections of TP removal rate is 78.2%.