【作者】 马群；

【导师】 吴晓芙；

【作者基本信息】 中南林业科技大学 ， 环境科学， 2009， 硕士

【摘要】 不同种类的矿物吸附剂被作为去除污水中重金属离子的吸附剂材料,有些被用在人工湿地污水处理系统中。废水中重金属离子浓度与废水种类相关,并随时间变化,其对湿地生物(植物、微生物与水生动物)的生长与活性有负面作用,从而影响系统的处理效率与稳定性。本研究提出构建缓冲系统的新思路,通过选用高吸附容量的吸附填料在湿地系统中建立一个前置吸附缓冲单元,用以降低进入后续单元的污染物质(尤其是重金属离子)浓度的水平,从而保证湿地植物的正常生长和处理系统的正常运行。目前,人工湿地填料的吸附性能比较尤其是缓冲单元建立方面研究数据资料很少。本研究选择以人工沸石、天然沸石、膨胀蛭石和硅藻土(或红壤)四种矿物填料为吸附剂,在吸附剂浓度100 g/L和起始离子浓度50～500 mg/L内,配置了水溶液与污水溶液中Cd2+和Zn2+与NH4+等单一与混合离子吸附的对比试验。同时在中试组合人工湿地污水处理系统中,构建立了一个前置吸附缓冲单元,开展了生活污水与实验室废水混合污水处理的中试试验。本试验目的是分析矿物吸附剂的吸附特性,考察吸附缓冲单元在污水处理中的作用与效果,为人工湿地吸附填料的选择、系统构建和运行实践提供基础试验数据与技术支持。实验结果表明：1.在本试验条件下,Langmuir与Freundlich等温方程与四组分吸附模型均能较好的模拟离子的平衡吸附行为。2.处理效率与经济成本综合分析结果表明,在四种矿物吸附剂中,天然沸石和膨胀蛭石是人工湿地系统去除锌、镉离子的最佳填料,单位投资成本分别为：6.125元/m3和8.98元/m3。3.混合离子吸附试验验证了共存离子间存在竞争吸附,污水配置的混合离子体系中各离子的吸附密度均小于纯水配置的混合离子体系。4.在中试系统中,采用矿物填料建立的缓冲系统有很好的缓冲效果,在缓冲单元内植物生长生长正常,在出水水质达标的前提下,其缓冲期可达60天左右；缓冲单元内部的曝气系统对整个缓冲单元的三要素起到了积极的作用,提升了整个系统的缓冲及处理能力。更多还原

【Abstract】 Various types of minerals have been selected as potential adsorbents for the removal of metal pollutants from aqueous solutions. Some of them have been utilized as fillers or liner materials in constructed wetlands and landfills for waste disposal. The concentration of metal pollutants in wastewaters varies to a large extent not only with wastewater type but also with time. This has a negative impact on the normal growth of plants as well as on the activity of micro-organisms in the open wetland system. The introduction of an adsorption buffer unit using materials with a high adsorption capacity into a wetland system can thus improve both the treatment capacity and sustainability. There have been so far very few reports concerning comparison of the adsorption capacity among different mineral absorbents and establishment of a buffer unit using mineral adsorbent in constructed wetland system for treatment of wastewaters.The present study was conducted using synthetic zeolite, natural zeolite, swelling vermiculite and the diatomaceous earth (or red soil) as absorbents to compare their ability to adsorb Zn2+ and Cd2+, NH4+ in single and mixed metal ion systems preapared in aqueous solutions and wastewaters within the range of initial ion concentration 50-500 mg/L at a given adsorbent concentration level (100 mg/L). A pilot buffer unit using relevant adsorbents was further established in the constructed wetland system built for wastewater treatment. The objective of this study was to provide basic data and information for selection of proper adsorbent fillers that can be used for establishment of buffer unit in constructed wetland systems. The main results obtained from this study are summarized as follows:1. The equilibrium ion adsorption can be well described by the Langmuir isotherm, the Freundlich equation and the four adsorption component model under the tested conditions.2. Among the minerals tested, the natural zeolite and the swelling vermiculite were found to be the best wetland fillers in terms of cost effective for removal of Cd2+ and Zn2+ ions. Their costs were estimated, respectively, as 6.125 and 8.98 Yuan/m3.3. Adsorption competition among coexisting ionic species was observed in the mixed metal ion systems. The ion adsorption quantity in mixed ionic species system was found to be higher in sewage than in aqueous solutions.4. Establishment of the pilot buffer unit using the selected adsorbent enhanced the treatment efficiency by providing an adequate condition for normal growth of plants in the constructed wetland system. The buffering effect lasted for more than 60 days within which the water quality reached the national wastewater discharge standard in the outlet. Aeration in the buffer unit was found to be effective in improving the treatment efficiency and stability.更多还原