人工湿地填料磷去除效果的影响因素分析

Influencing Factors of Phosphorus Removal Performance of Constructed Wetlands Substrates

为分析人工湿地填料磷去除效果的影响因素,选取页岩、粗砾石、铁矿石、麦饭石等不同填料进行等温磷吸附实验和室内小试磷去除研究。结果表明,填料类型和粒径影响填料磷吸附性能。上述填料磷吸附性能依次为页岩>铁矿石>麦饭石>粗砾石且页岩最大磷吸附量随粒径增加而减小。水力负荷(HLA)变化对不同填料磷去除效率影响效果不同,当HLA从200mm·d-1降至142.8mm·d-1时,粗砾石构建湿地总磷去除率增加大约10%;麦饭石因为吸附渐进饱和总磷去除率呈现出不断下降趋势;铁矿石可能受微生物影响导致Fe等金属元素释放,总磷去除率从大约6%(HLA=200mm·d-1)上升至35%(HLA=142.8mm·d-1)左右;页岩受HLA变化影响较小,总磷去除率基本稳定在80%以上。综合上述实验结果发现填料种类、粒径及水力负荷均影响湿地填料磷去除效果。

In order to analyze the factors that influenced phosphorus removal performance of constructed wetlands substrates, shale, course gravel, ironstone and hornblende were used to conduct the phosphorus isothermal adsorption experiment and indoor pilot-scale phosphorus removal research. Phosphorus isothermal adsorption experimental results indicated that substrate types and grain sizes could both influence phosphorus removal capacities. There was an order in rank for phosphorus adsorption capacities of the four substrates mentioned above： shale〉 ironstone〉hornblende〉course gravel and the maximum phosphorus adsorption capacity of shale increased as the grain size of the material decreased. TP removal efficiency of indoor-pilot scale constructed wetlands with different substrates varied with hydraulic loading rate （HLA）. When HLA was declined from 200 mm·d^-1 to 142.8 mm·d^-1, TP removal rate of course gravel bed constructed wetland increased about 10%, while hornblende bed appeared depressive trend since the substrate achieved saturated adsorption gradually. Ironstone that was maybe affected by the action of microorganisms led to the increase of TP removal rates from about 6%（ HLA=200 mm·d^-1） to approximately 35% （142.8 mm·d^-l）, owing to the release of element Fe. Shale bed was hardly affected by the change of HLA, and the TP removal rate maintained above 80% during the experimental period. These results implied that substrate types, grain size and hydraulic loading rate were the factors that influenced phosphorus removal performance of constructed wetlands substrates.