生物滞留系统中径流雨水磷的迁移转化规律

Translocation and Transformation of Phosphorus in Rainwater Runoff in the Bio-Retention System

基于生物滞留系统对雨水的处理效果,对其进行模拟径流雨水进水试验,通过连续提取法检测生物滞留系统土壤渗滤介质不同深度(0、5、15、35 cm)处交换态无机磷(Ex-P)、铝磷(Al-P)、铁磷(Fe-P)含量,并监测系统出水TP。结果表明,土壤渗滤介质对Ex-P、Al-P、Fe-P的吸附是从上至下逐层进行、逐层减弱的,Ex-P转化为Al-P、Fe-P,同时Al-P转化为Fe-P,因此Ex-P含量逐层减少,而Al-P、Fe-P逐层累积。系统对径流雨水中TP的去除率在90%以上,其中未被植物利用的TP体现为水-土壤-根系-生物系统内磷的动态平衡。

Based on effects of a bio-retention system on rainwater,a simulation test on rainwater runoff was carried out.With the sequential extraction method,contents of exchangeable inorganic phosphorus（ Ex-P）,aluminum phosphate（ AlP） and iron phosphorus（ Fe-P） in the filtration medium or soil of the bioretention system at different depth（ 0,5,15 and35 cm） were determined and TP in the effluent of bio-retention system was also monitored. Results show that the adsorption of Ex-P,Al-P and Fe-P by the soil medium decreased with the depth,layer by layer from the top to the bottom. During the process of adsorption,Ex-P gradually transformed into Al-P and Fe-P,while,Al-P did into Fe-P. As a result,ExP decreased in concentration while Al-P and Fe-P increased with the depth. About 90% of the TP in the runoff rainwater was intercepted and removed by the system. The phosphorus,not absorbed by plants,remained in the system,being a part of the dynamic TP balance of the water-soil-root-biome system.