植物物种丰富度对水培微宇宙中硝态氮去除的影响

Effects of plant species richness on nitrate removal from wastewater: A hydroponic microcosm experiment

在沙基质的人工湿地中植物多样性能够提高污水去除效果,但无基质水生系统中植物多样性对除氮效应的影响还未知。本研究在45个水培微宇宙(53cm×37.5cm×18.5cm)中配置了4个物种丰富度梯度(1、2、3和4),并定期供给硝氮为唯一氮形态的模拟污水,氮载荷率为548.5gN·m-2·a-1。结果表明:物种丰富度对出水中氮去除有显著效应,4个种系统出水总无机氮浓度(54.3mg·L-1)明显低于单种系统(129.0mg·L-1);物种丰富度显著提高群落生物量,4个种微宇宙系统群落总生物量为1621.6g·m-2,高于单种群落的1032.7g·m-2。水培微宇宙的氮平均移除速率为466.8gN·m-2·a-1,不低于已有报道的全尺度人工湿地的去除能力,同时,4个种的系统比单种系统约高13%,因而可以通过物种多样性配置提高人工湿地效能。

Previous studies have shown that the plant diversity in constructed wetlands with sand substrate can improve the removal efficiency of wastewater contaminants. However, the effects of plant diversity in the aquatic system without substrate on nitrogen removal are unknown. In this paper, 45 hydroponic microcosms （53 cm × 37.5 cm× 18.5 cm） with 1, 2, 3, and 4 plant species were installed, and periodically applied with nitrate as the sole nitrogen source at a load- ing rate of 548.5 g N m-2 a-1 to simulate wastewater. The results showed that species richness had significant effects on the effluent nitrogen removal. The total inorganic nitrogen concentration in the effluent of four species systems （54.3 mg L-1 ） was obviously lower than that of monocul- ture systems （ 129.0 mg L-1 ）. The community biomass increased significantly with the increase of species number. The total biomass in four species systems （ 1621.6 g m-2） was higher than that in monoculture systems （1032.7 g m-2）. The average nitrogen removal rate in the hydro- ponic microcosms was 466.8 g N m-2 a-1, not lower than that in the previously reported full- scale constructed wetlands. Meanwhile, the nitrogen removal rate in four species systems was 13% higher than that in monocuhure systems, indicating that the improvement of nitrogen remov- al efficiency in constructed wetlands could be achieved by increasing plant diversity.