The aim of the present study is to probe the relation between plant growth and its decontamination effect in constructed wetlands. Four species were studied in the small-scale mono-cultured constructed wetlands,which were fed with domestic wastewater. Plant growth indexes were correlated with contaminant removal performance of the constructed wetlands. Wetlands planted with Cyperus flabelliformis Rottb. showed the highest growth indexes such as shoot growth,biomass,root activity,root biomass increment,and the highest contaminant removal rates,whereas wetlands planted with Vetiveria zizanioides L. Nash had the lowest growth indexes and the lowest removal rates. Above-ground biomass and total biomass were significantly correlated with ammonia nitrogen removal,and below-ground biomass with soluble reactive phosphorus removal. Photosynthetic rate had higher correlation with nitrogen removal in these species. Root activity and root biomass increment was more correlated with 5 d biochemical oxygen demand removal. Chemical oxygen demand removal had lower correlations with plant growth indexes. All four species had higher removal rates in summer and autumn. The results suggest that the effect of plant growth on contaminant removal in constructed wetlands were different specifically in plants and contaminants.
Xiu-Yun Cheng Ming-Qiu Liang Wen-Yin Chen Xu-Cheng Liu Zhang-He Chen
[Objective] The research aimed to study the influence of temperature on the growth of Hydrilla verticillata in the wastewater treatment process.[Method] By using the single factor experiment design,four temperatures which were 5,15,25 and 35 ℃ were set.The growth situation of H.verticillata under the different temperatures was observed in the treatment process of domestic sewerage.[Result] H.verticillata grew luxuriantly at 35 and 25 ℃.Via the cultivation of 15 days,the plant length,branch number,root number and biomass of H.verticillata respectively increased 2.8 and 1.2 cm,7.0 and 5.9 branches,6.2 and 3.7 roots,21% and 25%,which were all significantly or extremely significant higher than that at 5 ℃.Under the cultivation condition of 15 ℃,H.verticillata grew slowly.The increment of plant length,branch number and root number were higher than that at 5 ℃,but they had no significant difference.[Conclusion] During 5-35 ℃,the higher temperature could promote the growth of H.verticillata in wastewater treatment process.
为探讨梭鱼草(Pontederia cordata L.)作为人工湿地植物的应用潜力,通过在室外用瓷盆(上直径80 cm,底直径50 cm,高45 cm)构建单种潜流湿地,比较了梭鱼草与常用的人工湿地植物芦苇(Phragmites australis Trin.e x S t e u d.)在人工湿地中对营养物质和重金属Cd2+和Pb2+的去除率.结果显示,梭鱼草对总氮(TN)和生化需氧量(BOD5)的去除率显著高于芦苇(P<0.05).两种植物湿地对Cd2+和Pb2+的去除率无显著差异.两种植物体内Cd2+和Pb2+的含量均是根>茎>叶,根部为主要的富集器官.污水停留2 d和停留7 d,两种湿地对营养物质的去除率差别不大,而对重金属的去除率,停留7 d显著高于停留2 d,表明人工湿地对重金属的去除比对营养的去除要慢一些.研究表明,梭鱼草是一种具有良好景观效果和较高去污率的湿地植物,在人工湿地中具有较好的应用潜力.
