经济植物湿地处理洱海流域低污染河水的性能

为研究水生经济植物湿地对洱海流域低污染河水的处理效果,在洱海北部罗时江入湖河口建设了面积为2 hm2水生经济植物湿地,其中水生经济植物包括4种水生蔬菜——空心菜(Ipomoea aquatica Forsk)、薄荷(Mentha haplocalyx Briq.)、水芹菜〔Oenanthe javanica (Blume) DC〕、茭白〔Zizania latifolia (Griseb.) Stapf)〕,3种药用植物——香茶菜〔Rabdosia amethystoides (Benth.)〕、灯心草(Juncus albesens)、水菖蒲(Acorus calamus L.)和1种观赏植物——美人蕉(Canna indica L.). 结果表明:湿地对TN、TP、NH₃-N、NO₃--N均具良好去除效果,近3个月运行期间,平均去除率分别为66.4%、60.3%、60.4%和73.2%；但该湿地对COD_Mn的平均去除率仅为5.0%. 不同湿地水生经济植物表现出了不同的水质净化能力,其中TN平均去除效率表现为水芹菜>香茶菜>美人蕉>茭白>空心菜>薄荷,TP平均去除效率表现为水芹菜>薄荷>美人蕉>香茶菜>空心菜>茭白. 研究表明,水生经济植物湿地对低污染河水具有良好的净化效果,在洱海流域具有推广意义. 

Studies on the Treatment of Slightly Polluted River Water using Constructed Wetland with Economic Plants in Erhai Lake Valley

Abstract: A constructed wetland of two hectares with aquatic economic plants near the estuary of the Luoshijiang River in the north of Erhai Lake was built, and its purification ability for slightly polluted river water was studied. The aquatic economic plants adopted in this wetland included four kinds of aquatic vegetables (Ipomoea aquatica Forsk, Mentha haplocalyx Briq., Oenanthe javanica (Blume) DC, Zizania latifolia (Griseb.) Stapf), three kinds of medicinal plants (Rabdosia amethystoides (Benth.), Juncus albesens, Acorus calamus L.), and one kind of ornamental plant (Canna indica L.). It was shown that the wetland had satisfactory removal performance for total nitrogen, total phosphorus, ammonia nitrogen and nitrate nitrogen, with the average removal efficiencies of 66.4%, 60.3%, 60.4% and 73.2%, respectively, during nearly three months of runtime. However, it had low removal efficiency with an average value of 5.0% for permanganate index, which was presumed to be due to low concentration of organics in the influent and production of organics from the wetland itself. It was found that different aquatic economic plants in the wetland showed different water purification abilities. Purification performance of the total nitrogen was in the order:Oenanthe javanica (Blume) DC>Rabdosia amethystoides (Benth.)>Canna indica L.> Zizania latifolia (Griseb.) Stapf)>Ipomoea aquatica Forsk>Mentha haplocalyx Briq, and total phosphorus was in the order:Oenanthe javanica (Blume) DC>Mentha haplocalyx Briq>Canna indica L.>Rabdosia amethystoides (Benth.)>Ipomoea aquatica Forsk>Mentha haplocalyx Briq. This study revealed that the constructed wetland aquatic economic plant has a fine purification effect for slightly polluted water and is worthy of promotion in Erhai Lake Valley.