人工湿地植物量及其对净化效果影响的研究

人工湿地污水处理系统中,植物对污水净化效果起着非常重要的作用,而植物量是植物生长的关键参数之一。为了明确植物量对污水处理效果的影响,在2002—2008年期间,详细测定了芦苇(Ph.australis Trin)、再力花(Thalia dealbata)、荻(M.sacchariflorus)和美人蕉(Canna indica)4种典型湿地植物不同年度的生物量、不同生长阶段的生物量、生物量年产率,以及同期湿地COD、BOD5、TN和TP等的去除率。结果表明:湿地植物在栽植成活、稳定生长以后,至少要再经过1个以上的生长周期才能完全适应湿地环境,达到生物量的最大值,其中芦苇根系和茎叶生物量显著高于其他植物;同种植物的植物量与COD、BOD5、TN去除率呈显著正相关,与TP相关性不强;植物量随生长周期的变化对湿地净化能力的影响显著,确定合理收割期有利于湿地的稳定运行;不同种类植物生物量年产率与各种污染物的去除率均显著相关,芦苇、再力花和美人蕉均具有较高的生物量年产率,污染物去除能力较好。在试验范围内,芦苇湿地的运行稳定性最好,再力花湿地具有最强的脱氮能力,美人蕉湿地能快速形成规模、实现稳定运行,这些为构建不同特点和不同需要的湿地提供了重要参考。

Phytomass and its impact on the pollutant removal ability of constructed wetland

In wastewater treatment system of constructed wetland, plants play a very important role in the purification efficiency of wastewater. Phytomass is one of the key parameters of plant growth. In order to investigate the effect of constructed wetland biomass on wastewater treatment efficiency, the biomass and its annual output of reed (Ph. australis Trin), Powdery Thalia(Thalia dealbata), Sweetcaneflower Silvergrass (M. sacchariflorus) and canna(Canna generalis)were determined in different years and different stages of growth from 2002 to 2008, and the removal rates of constructed wetlands for COD, BOD_5, TN and TP, etc. were also measured. The results showed that it took wetland plants at least more than one growth cycle to adapt themselves to wetland environment and to obtain the maximum biomass. Reed had a significantly higher root and leaf biomass than other plants. Phytomass for the same plants had a significantly positive correlation with removal rate of COD, BOD, and TN. Phytomass change with growth cycles exerted a remarkable impact on the treatment ability of constructed wetlands. So a reasonable harvest frequency established was favorable for the stable operation of constructed wetlands. Annual biomass output of different plants displayed a significant correlation with re-moral rate of pollutants. Reed, powdery thalia, and canna with higher annual biomass output had better removal efficiency of pollut-ants. Within the scope of this study, the stability of reed wetlands was best, and powdery thalia wetlands had the highest denitrifica-tion capacity, canna wetlands had a much shorter start-up period, which quickly achieved the stable operation. All these results pro-vided an important reference for the construction of wetland with different characteristics and requirements.