4种湿地植物混合群落净化污染水体的试验

Experiment of Mixed Communities with Four Kinds of Wetland Plants for Purification of Polluted Water Body

湿地生态系统中的植物群落物种组成对水体的自然净化效果具有重要的影响。文中以广西桂林会仙湿地4种植物[苦草(Vallisneria natans)、芦苇(Phragmites australis)、华克拉莎(Cladium chinense)、美人蕉(Canna indica)]构建表面流湿地系统,进行生活污水污染水体的净化效果研究,同时,以会仙湿地污染严重水域(七星码头)生长的植物[菹草(Potamogeton crispus)、黑藻(Hydrilla verticillata)、凤眼莲(Eichhornia crassipes)、芦苇]构建对照系统进行对比分析。结果表明:苦草组(苦草+芦苇+华克拉莎+美人蕉)及菹草组(菹草+黑藻+凤眼莲+芦苇)对污染水体中TP、TN和COD_(Mn)均有明显净化效果。苦草组对TP、TN、COD_(Mn)的去除率分别为54.26%~85.25%、53.80%~83.64%、36.27%~73.62%;菹草组对TP、TN、COD_(Mn)的去除率分别为49.14%~63.81%、45.77%~60.81%、30.25%~52.26%。苦草组具有更高的水体净化能力,经处理后TP、TN、COD_(Mn)的平均出水质量浓度分为0.07、0.76、9.41 mg/L。2组植物群落系统对TP、TN、COD_(Mn)的去除效果均表现为夏、秋季高于冬、春季。将苦草、芦苇、华克拉莎、美人蕉组成的植物混合群落移植到会仙湿地污染严重水域进行原位强化修复,具有较强的可行性。

The species composition of plant communities in wetland ecosystems has an important impact on the natural purification of water.In this paper surface flow wetland system was constructed with four plants(Vallisneria natans,Phragmites australis,Cladium chinense and Canna indica)in Huixian Wetland in Guilin,Guangxi,in order to study the purification effect of water polluted by domestic sewage.At the same time,a control system was constructed with four plants(Potamogeton crispus,Hydrilla verticillata,Eichhornia crassipe and Phragmites australis)grown in the seriously polluted surface area(seven stars wharf)of wetland.Results showed that Vallisneria natans group(Vallisneria natans+Phragmites australis+Cladium chinense+Canna indica)and Potamogeton crispus group(Potamogeton crispus+Hydrilla verticillate+Eichhornia crassipe+Phragmites australis)had obvious purification efficiencyon total phosphorus(TP),total nitrogen(TN)and COD_(Mn)in polluted water.The removal rates of TP,TN and COD_(Mn)in Vallisneria natans group were 54.26%~85.25%,53.80%~83.64%,36.27%~73.62%,respectively.The removal rates of TP in Potamogeton crispus group were 49.14%~63.81%,45.77%~60.81%,30.25%~52.26%,respectively.Vallisneria natans group had a higher purification capacity,and the average effluent concentrations of TP,TN and COD_(Mn)were 0.07,0.76,9.41 mg/L,respectively.The removal effects of two groups of plant community systems on TP,TN and COD_(Mn)were higher in summer and autumn than in winter and spring.It is highly feasible to transplant the mixed plant community consisting of Vallisneria natans,Phragmites australis,Cladium chinense and Canna indica to strengthen in situ remediation of seriously polluted waters in Huixian Wetland.