Effect of polyculture of woody and herbaceous plant with different ecological niche in constructed wetlands (CWs) on wastewater treatment is unclear. Herein, three kinds of polyculture CWs were constructed to treat domestic wastewater: woody polyculture system (W, Nerium and Hibiscus), herbaceous polyculture system (H, Acorus and Typha), woody and herbaceous polyculture system (WH, Nerium, Hibiscus, Acorus and Typha) and non-planted system (N) as control. The seasonality removal performance of pollutant, activities of urease and phosphatase, microscopic characteristics of roots were measured. Results showed that the average removals of COD, TN and TP in WH were significantly higher than that in the other systems. Interspecies competition existed in WH system, while the difference in terms of biomass gradually diminished. Furthermore, the root lengths, area, volume and tip number were higher compared to the other systems. The correlation between the removal rate of TP and activity of phosphatase in upper and bottom layer of CWs showed the opposite tendency, the distribution of plant roots in polyculture essentially impact TP removal rate in CWs. Our results provide the necessary insights for appropriately selecting different plant types for doing polyculture in CWs.

中文翻译：

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木本和草本植物混养在人工湿地中处理生活污水的性能。

在人工湿地（CWs）中，不同生态位的木本和草本植物混养对废水处理的影响尚不清楚。在此，构建了三种混养CW来处理生活废水：木质混养系统（W，Nerium和芙蓉），草本混养系统（H，Acorus和香蒲），木质和草本混养系统（WH，Nerium，Hibiscus，Acorus和香蒲）和非种植系统（N）作为对照。测量了污染物的季节性去除性能，脲酶和磷酸酶的活性，根的微观特性。结果表明，WH中COD，TN和TP的平均去除率显着高于其他系统。WH系统存在种间竞争，而生物量方面的差异逐渐减小。此外，根长，面积，体积和叶尖数均比其他系统高。污水中上层和下层TP的去除率与磷酸酶活性之间的相关性呈相反的趋势，混养中植物根系的分布对污水中TP的去除率有重要影响。我们的结果为适当地选择不同的植物类型进行CW混养提供了必要的见识。