【作者】 李瑞玲；

【导师】 李倦生； 黄妍；

【作者基本信息】 湘潭大学 ， 环境工程， 2010， 硕士

【摘要】 环境污染制约经济发展,危害人类的健康,已经成为人们重点关注的环境难题。酸性重金属废水主要来源于矿山开采、金属制造加工等行业,由于其重金属的毒性而严重危害环境与人类的生存。人工湿地作为一种生态化污水处理技术,可以高效地去除废水中总磷总氮和重金属,并且出水水质稳定,成本低,运行维护简单,不会造成二次污染,在工业废水处理中的应用不断受到重视。水生植物在人工湿地系统脱除重金属的过程中发挥着重大作用,除了直接对重金属的吸收作用外,还分泌有机物络合重金属,为微生物提供栖息环境,改善湿地系统对重金属脱除能力。研究酸性条件下水葱、香蒲、芦苇、灯芯草、野茭白和芦竹六种模拟人工湿地系统在不同停留时间和不同污染负荷时,对重金属的去除效果,确定对各种重金属去除效果最佳的植物和每一种植物最适合去除的重金属污染物,并研究湿地植物体内重金属的含量及分布规律,获得以下结果:(1)重金属浓度越高对植物的毒害作用越大,且随着时间的延长植物的中毒现象越严重。(2)在整个实验期内,随着水力停留时间的增长,各模拟系统液相中pH值均逐渐上升,与对照系统相比,模拟湿地植物系统液相中pH值的上升速度更快。这一现象表明,除了基质砂石和土壤中某些碱性物质以及微生物代谢产物的中和作用外,植物具有一定的调节作用,但这种调节作用在不同种类的湿地植物间无较大的差异,同时系统液相pH值变化速度与各重金属初始投加浓度密切相关,重金属初始投加浓度较低时,系统液相中pH值变化更为显著。(3)六种人工湿地系统液相中铜锌铅镉的浓度都随时间的延长而降低,表明六种模拟人工湿地系统对铜锌铅镉四种污染物都有较好的去除效果。本研究得出水葱系统、灯芯草系统、芦竹系统最适合用于处理含铜和铅的废水;香蒲系统、芦苇系统最适合用于处理含铜、锌的废水;野茭白系统最适合于处理含锌的废水。(4)六种植物的根、茎叶组织对同一重金属的吸收和积累都有差异。除芦苇以外,铜、锌、铅、镉四种重金属都主要积累于其它植物的根部,茎叶部分含量相对较低。(5)镉和铅在灯芯草细胞内主要结合位点是细胞壁和细胞溶质部分,细胞核和叶绿体部分及线粒体部分中铅、镉的含量均较低。(6)在三种不同初始投加浓度下,铅镉在灯芯草体内以去离子水提取态、氯化钠提取态和醋酸提取态为主,即铅和镉在灯芯草体内主要与蛋白质、果胶酸盐结合,或者是形成难溶于水的磷酸盐,吸附在根系,使污水得以净化。更多还原

【Abstract】 Hindering economic development and causing damage to human health, water pollution has developed into a worldwide environmental problem. Acid wastewater containing heavy metals is mainly resulted from mining, metal processing industries and has been seriously harmed the environment and human survival.Man-made wetlands as an ecological wastewater treatment technology can not only efficiently remove nitrogen and phosphorus in waste water with heavy metals, but also is of stable water quality, simple operation and maintenance, as well as low cost without secondary pollution. Therefore, it has attacted more and more attention in industrial wastewater treatment. In man-made wetland system, aquatic plants play an important role in the process of the removal of heavy metals. Not only can they directly absorb heavy metals, but also secret organic to complex heavy metals generated in the absorption process.Therefore it can provide habitat for microbes and enhance heavy metal removal capacity in wetland system. With different residence time and under different pollution load and acidic condition, through study on the heavy metals removal effect of shuicong, cattail, reeds, rushes, wild rice stem, and arundo donax in the six simulated wetland system, we find out the best plant most suitable for removal of heavy metals and the perfect match between each plant and heavy metals. Also, we study on the content and distribution of heavy metals in wetland plants. The results are as follows:(1) The higher the concentration of heavy metals on the plant, the greater the toxicity is. And with time passing by, plants toxicity becomes more serious.(2) With hydraulic retention time passing by, pH value of the simulation system gradually increased in liquid phase, as compared with the control system, the liquid pH value increases faster. The phenomenon indicates that except for the neutralization among gravel substrate, some basic material and microbial metabolites in soil, plants are endowed with regulation ability, which has little difference among different kinds of wetland plants.Accordingly the change rate of pH valuein liquid phase is closely related with the initial dosing concentration of each heavy metals.When the initial dosing concentration is comparatively low, the change rate of pH valuein liquid phase is more significant.(3)The concentration of copper,zinc,lead,cadmium, and have decreased with time in the six simulated wetland system, which indicates that the six simulated wetland system has a good effect on lead,copper, cadmium and zinc removal.The study finally indicates that with different concentrations of initial dosing, the best purification system for wastewater with copper and lead is Shuicong, rush and arundo donax system, for copper and zinc is typha and reed system and for zinc is wild rice stem system.(4)Six roots,stems,leaves the same effect of absorption and accumulation of heavy metals vary. Copper,zinc,lead,cadmium are accumulated in the roots of other plants except reeds,much less in the stems and leaves.(5) 0f cadmium and lead in the rushes, the major cell binding site is part of the cell wall and cytosolic, nuclear and chloroplast and mitochondrial part of some lead and cadmium were lower.(6) In the initial dosage of three different concentrations, lead and cadmium in the body in the rush to extract state of deionized water, sodium chloride and acetic acid extractable extractable mainly lead and cadmium in the rush that is the main protein in vivo , pectate binding, or insoluble in water, the formation of phosphate adsorption on the root system, the sewage will be purified.更多还原