几种植物在生长过程中对人工湿地污水处理效果的影响

不同的植物及植物的不同生长阶段对人工湿地系统污水处理效果都有影响。对几种华南地区常见的湿地植物在其不同生长阶段处理污水的效果进行了研究,采用了不种植物的沙滤系统作对照。结果表明:(1)植物生长过程中,植物高度能反映污水处理效果总体上的变化;(2)在植物的生长过程中,各人工湿地系统污水处理能力总体上持续增强,各水质指标pH、DO、TN、NH3-N、NO3-N、TP和CODCr等均呈下降趋势,其中TP和CODCr呈逐步下降,pH、DO、TN、NH3-N、NO3-N则呈现锯齿形波动,但总体上仍是下降过程;(3)植物系统氮处理能力好于无植物沙滤系统,而对磷TP和CODCr的去除则恰好相反;(4)不同植物对人工湿地污水的处理效果影响不明显。研究结果对探讨人工湿地污水处理规律和植物在人工湿地中的作用提供了新的科学依据,并为指导人工湿地工程的运行提供了参考。

Effects of several plants species in their growth on the treatment of constructed wetlands

Constructed wetland is efficient in wastewater treatment which is consisted of plants, microorganisms, substrates and so on. Plants are important in constructed wetlands and play crucial functions in the system. The macrophytes stabilize the surface of the beds, provide good conditions for physical filtration, prevent vertical flow systems from clogging, insulate the surface against frost during winter, and provide a huge surface area for attached microbial growth. Their roots give off oxygen to substrate to increase aerobic degradation of organic matter and nitrification. Plants have effect on the constructed wetland treatment according to different species and different growth phrases. In this study, a batter of constructed wetland microcosms were built to test the purification effi- ciency along the process of plant growth of different plant species. The comparation of the treatment between the microcosms with plants and without plants was also considered. Based on the experiments, the following results were obtained. (1) The height of the plants can reflect the purification efficiency when the plants grew. (2) The treatment capabilty of the constructed wetland microcosms had been rising when the plants grew. And the water quality items, including pH, TN, NH3-N, NO3-N, TP and CODCr all reduced as a whole as the plants grew. Among them, TP and CODCr decreased gratually, but pH, TN, NH3-N and NO3-N changed in shape of ser- ration in the same tendency. (3) All the groups could reduce the pollutions greatly, but the nitrogen removal was more efficient the microcosms with plants; while as to TP and CODCr, it was opposite. (4) Plants had little effect on wastes treatment. In this study, we provide new knowledge about the constructed wetland and the plants grew there, which will be of great help in the operation of such wastewater treatment.