生化尾水胁迫下湿地植物生理特性变化

检测植物处理污水厂生化尾水的效果和分析植物生理生长特性,为西北干旱半干旱地区人工湿地污水处理系统合理配置土著湿地植物提供理论依据。在复合垂直流-水平流人工湿地中种植芦苇和香蒲,生活污水处理装置的二级生化出水胁迫,植物移栽成活后和收割之前分别检测植物的生理、生长指标和光合参数。结果表明,COD_(Cr)、NH~+_4-N、TN、TP的去除率,种植植物期间分别为79.32%、85.69%、82.17%、91.76%,植物收割后分别为71.34%、58.45%、60.49%、89.86%;芦苇最高株高达到380 cm,香蒲最高株高达到320 cm;地上部分生物量香蒲最高达到4.15kg,芦苇最高达到7.55 kg;香蒲的净光合速率(P_n)分别增加了6.35%、3.99%、22.39%,芦苇的净光合速率(P_n)则分别增加了42.20%、5.26%、8.96%。2种湿地植物在污水胁迫下表现出一定的防御能力,但是抗污能力存在一定的差异。

Changes in the Physiology of Wetland Plants Stressed by Effluent from a Secondary Wastewater Treatment Plant

Wetland plants are important components of constructed wetland wastewater treatment systems. Pollutant removal efficiency in constructed wetlands is closely related to the growth and physiological characteristics of wetland plants. We examined the physiological characteristics of two plants (Phragmites australis and Typha) in a constructed wetland designed for purifying effluent from a secondary wastewater treatment plant (WWTP) and pollutant removal efficiency was analyzed. The objective was to provide a theoretical basis for the rational allocation of wetland plants for constructed wetland wastewater treatment systems designed for the arid and semi-arid regions of northwest China. Phragmites australis and Typha plants were transplanted to an artificial wetland with descending and ascending vertical flows and horizontal subsurface flow and stressed by the effluent from a secondary WWTP. The plant physiology, growth indicators and photosynthetic parameters of the two plants were tested after survival and before harvest over three days. The removal rates of CODCr, NH4+-N, TN and TP were, respectively, 79.32%, 85.69%, 82.17%, and 91.76% during the plant growing period and 71.34%, 58.45%, 60.49% and 89.86% after the plants were harvested. The maximum height and above ground biomass of Phragmites australis were up to 380 cm and 7.55 kg, and the height and aboveground biomass of Typha were up to 320 cm and 4.15 kg. The net photosynthetic rate (Pn) of Typha for each treatment increased by 6.35%, 3.99%, and 22.39%, respectively, and the net photosynthetic rate of Phragmites australis increased by 42.20%, 5.26%, and 8.96%, respectively. The two wetland plants showed some tolerance to wastewater stress, but the pollutant resistance of the two plants differed.