潜流湿地中填料的理化作用及对植物生长的影响

填料是潜流湿地的重要组成部分,它不但直接参与污染物的去除,而且对植物的生长和生理活动产生重要影响.本研究采用河北围场产沸石和秦皇岛产页岩,通过X射线荧光光谱和X射线衍射分析,确定了2种填料的元素组成和矿物组成,揭示了填料去除氮磷及缓冲H⁺的作用机理.研究表明:沸石和页岩都具有较发达的中孔结构,页岩对NH₄⁺-N的吸附能力小于沸石;页岩主要组成为CaCO₃,对PO₄^3--P的去除能力大于沸石,且对水中的H⁺有较好的缓冲作用.在处理酸性淀粉废水的小试系统中,页岩中的菖蒲和芦苇,其叶片相对绿度、茎根比、平均株高等指标均好于沸石中植物.种植在页岩中的菖蒲和芦苇,其根系活力分别为沸石中植物的3.7倍和1.6倍.页岩中菖蒲,地上部分吸收氮磷总量分别是沸石中的7.8倍和3.4倍;页岩中芦苇,地上部分吸收氮磷总量分别是沸石中的3.3倍和2.2倍.由于为植物提供了pH稳定的根系微环境,页岩比沸石更适合植物生长.

Physical and Chemical Effects and Plant Growth Suitability of Substrates in Subsurface Flow Wetland

Substrate,which not only takes part in the pollutant-removing,but influences the plant growth,plays an important role in subsurface flow wetland.With X-ray fluorescence measurement and X-ray diffractometer,the elements and minerals in zeolite and shale were confirmed,and the removal mechanics of nitrogen,phosphate and hydrogen ion in substrates were explained respectively.The investigation show that the zeolite has abounded with micropores and mesopores,while the shale has only mesopores,which causes the NH₄⁺-N adsorption capability of the shale is less than zeolite.The PO₄^3--P removal and hydrogen ion buffer capacity of shale are greater than those of zeolite because CaCO₃ is one of the main contents of shale.In pilot-plant system to treat starch waste water,the reeds and acorus aclamuc were either planted in shale and zeolite,and the phytum's indexes in shale including relative green concentration,average plant height,root stem ratio were higher than those in zeolite.The root vitality of reeds and acorus aclamuc planted in shale were 3.7 and 1.6 times of those in zeolite respectively.Total nitrogen and phosphorus contents in the plant organization of acorus aclamuc in shale were 7.8 and 3.4 times of those in zeolite;total nitrogen and phosphorus contents in the plant organization of reeds in shale were 3.3 and 2.2 times of those in zeolite.The results indicate that shale provides a steady pH for the plant's root in the acid waste water and it is more suitable for plant growth than zeolite.