2种漂浮植物对再生水水质净化能力比较

COMPARISON OF PURIFICATION OF RECLAIMED WATER QUALITY BY TWO KINDS OF FLOATING PLANTS

选取2种常用水生漂浮植物凤眼莲与大薸作为研究对象,以某大型再生水厂再生水作为培养介质,研究对再生水中氮、磷的深度净化能力。实验结果表明:实验期间,凤眼莲相较于大薸,单株生物量更大,且增殖更迅速。在相同种植密度(24株/m^2)下,凤眼莲和大薸生长率分别为165,56. 8 g/(m^2·d),对TN去除率分别为96. 3%和73. 7%,去除负荷为374,286 mg/(m^2·d),大薸组对磷的去除效果优于凤眼莲组,去除率分别达到100%和94%,对磷的去除负荷分别为39,42 mg/(m^2·d);但是,实验进行10 d后,大薸出现叶片发黄、根部腐败状况,导致水体中氮、磷含量升高,而凤眼莲长势良好,去除效果能够保持。因此,对比2种植物的生长特点及对氮、磷的去除能力,优先选用凤眼莲作为再生水净化植物,如选用大薸,则应在腐败前进行打捞处理,避免腐败后氮、磷重新进入水体形成污染。

Eichhorniacrassipes( Mart.) Solms and Pistia stratiotes,two kinds of common hydrophyte,were selected as research objects to study their ability to purify nitrogen and phosphorus in the reclaimed water. The results showed that:Eichhorniacrassipes( Mart.) Solms had a greater biomass and rapider proliferation than Pistia stratiotes during the experiment;under the condition of the same planting density( 24 strains/m^2),the growth rates of Eichhorniacrassipes( Mart.) Solms and Pistia stratiotes were respectively 165 g/( m^2·d) and 56. 8 g/( m^2·d),the removal rates of total nitrogen were 96. 3% and73. 7%,and the removal load was 374 mg/( m^2·d) and 286 mg/( m^2·d);Pistia stratiotes had a better phosphorus removal efficiency than Eichhorniacrassipes( Mart.) Solms,the removal rate was 100% and 94%,respectively,the phosphorus removal load of Eichhorniacrassipes( Mart.) Solms and Pistia stratiotes was respectively 39,42 mg/( m^2· d). Ten days after the experiment,Pistia stratiotes had yellow leaves and rotten roots,which resulted in the increase of nitrogen and phosphorus contents in water,while Eichhorniacrassipes( Mart.) Solms grew well,and the removal effect could be maintained. Therefore,through comparison of the growth characteristics of the two plants and their abilities to remove nitrogen and phosphorus,Eichhorniacrassipes( Mart.) Solms could be preferentially selected as the purification plant of reclaimed water. If Pistia stratiotes was selected,fishing treatment should be carried out before decaying,in order to avoid the pollution caused by nitrogen and phosphorus reentering into the water body after decaying.