湿地植物在城镇污水处理系统中的作用特性研究

将不同类型湿地植物如凤眼莲、荇菜、稗草、黑藻、皇竹草、美人蕉等,引入城镇污水处理系统,考察其对污染物的去除效果和在湿地组合系统中的作用特性。盆栽实验发现,虽然植物对污水N、P营养元素的直接去除率分别只有14.0%～59.4%和8.6%～55.2%,但植物通过过滤、截留及加强有机物降解转化的作用,对水体中污染物的去除具有协同效应,使水体N、P的总去除率分别达65.4%～83.8%和43.5%～69.5%。将植物引入组合处理系统,中试实验结果表明,水体TN、TP和COD月平均去除率分别高达80.4%、74.3%和81.3%。与常规生化处理系统相比,处理效果大为增强,生化反应的能耗相对减少,出水水质较稳定,使湿地组合系统成为一种去N除P,防止水体富营养化的有效处理方法。

Characteristics of Constructed Wetland Hydrophytes and Its Contribution to Municipal Wastewater Treatment System

Removal efficiency of contamination and function of wetland hydrophytes including Eichhornia Crassipes, Nymphoides peltata,Acorus calamus L.,Cockspur grass,Hydrilla verticillata,Hybird Giant Napier and Cana generalis Bailey introduced into municipal wastewater treatment system was studied. Results of pot culture test showed that although direct removal efficiency of TN and TP from wastewater by hydrophytes was only 14.0%～59.4% and 8.6%～55.2% respectively,total removal efficiency of TN and TP in system reached 65.4%～83.8% and 43.5%～69.5% respectively through filtration and retention process as well as degradation and transformation of organics strengthened by hydrophytes. Results of pilot test indicated that monthly removal efficiency of TN,TP and CODcr in system reached 80.4%,74.3% and 81.3% after different types of wetland hydrophytes introduced into municipal wastewater treatment system. Compared with conventional biochemical wastewater treatment system,it was found that the treatment effect had increased greatly and energy consumption for biochemical reaction had been decreased relatively with steady effluent water quality,which is an effective method to prevent municipal water from eutrophication on the basis of removing N and P from wastewater by hydrophytes.