4种沉水植物对再生水中氮磷的去除速率和耐受范围

Removal and tolerance of 4 submerged plants to nitrogen and phosphorus in reclaimed water

【目的】研究4种沉水植物对再生水中氮、磷的去除速率和耐受范围，为以再生水作为补水的景观水体沉水植物的选择提供依据。【方法】以野外选取的伊乐藻（Elodea canadensis）、罗氏轮叶黑藻（Hydrilla verticillata）、菹草（Potamogeton crispus）和金鱼藻（Ceratophyllum demersum）4种沉水植物作为供试材料，设置含不同质量浓度TN和TP的再生水，测定有这4种沉水植物的再生水体中TN和TP质量浓度的变化，构建TN和TP质量浓度与培养时间的回归方程，并在回归方程的基础上，研究了4种沉水植物对再生水中的氮、磷的去除规律。【结果】在有4种沉水植物的再生水体中，TN和TP质量浓度均随着培养时间的延长呈负指数衰减变化，变化规律符合动力学方程y=ae-bt，其中y为TN或TP质量浓度，t为培养时间，a、b为反映植物净化能力的系数。a和b值不仅与沉水植物种类有关，而且与TN和TP初始质量浓度相关。罗氏轮叶黑藻对TN的去除能力最强，金鱼藻最低；伊乐藻对TP的去除能力最强，金鱼藻最小。菹草对氮素的耐受范围较宽，金鱼藻最窄；伊乐藻对磷素的耐受范围最宽，金鱼藻较窄。【结论】当再生水体中TN初始质量浓度为5~15 mg/L、TP初始质量浓度为0.5~1.5 mg/L时，罗氏轮叶黑藻和伊乐藻对氮磷营养盐的去除速率较高，可作为维持和改善再生水景观水体水质的先锋植物。

[Objective] Nitrogen and phosphorus removal rates and tolerances of 4 submerged plants were studied to provide basis for selection of plants growing in landscape reservoirs supplied with reclaimed water. [Method] Hydrilla verticillata ,Elodea canadensis , Potamogeton crispus and Ceratophyllum demersum were planted in reclaimed water with different total nitrogen （TN） and total phosphorus（TP） concentrations. TN and TP were measured during the experiment and regression equations between concentrations of TN and TP with time were established. Then, the removal of nitrogen and phosphorus was studied. [Result] TN and TP dissipated as the increase of plants planting time with negative exponent relationship. The capacity of plants purification is associated with not only plant species but also the TN and TP toph5 phyll phyll concentration. Hydrilla verticillata had the highest TN removal rate in reclaimed water whi llurn dernersumI had the lowest. Elodea canadensis had the highest TP removal rate, while urn dernersum had the lowest. Potarnogeton crispus had the widest nitrogen tolerance while urn dernersurn had the narrowest. Elodea canadensis had the widest phosphorus tolerance whi e Cera Cerato Cerato e Cera tophyllurn dernersum had the narrowest. [Conclusion] When TN concentration was 5-- 15 mg/L and TP concentration was 0.5-- 1. 5 mg/L, Hydrilla verticillata and Elodea canadensis had high removal rates and they can be chosen as pioneer plants to improve water quality of landscape lakes supplied with reclaimed water.