【作者】 雒维国；

【导师】 王世和；

【作者基本信息】 东南大学 ， 环境工程， 2005， 博士

【摘要】 人工湿地处理污水具有出水水质好,基建投资和日常运行费用低,维护管理方便等优点,且具有美学价值,特别符合国际上污水处理的小型化和分散化的最新环保理念,值得在中小城镇大力推广。但是,人工湿地对污染物的去除效果受到多种因素的影响和制约,诸如气温、基质属性、湿地植物、土壤微生物和湿地蒸发蒸腾等,而这些因素限制了湿地净化效果的进一步提高,目前正在成为限制湿地推广应用的瓶颈因素。本文针对湿地脱氮的主要影响因素,通过构建系列湿地模型,以污水厂初沉池出水作为湿地进水,在湿地稳定运行后,2002年9月至2005年4月,全面考察了影响湿地脱氮率因素和湿地脱氮率间的关系。研究内容主要包括:(1)不同湿地植物对脱氮效果的影响,试验首次研究了湿地植物光合作用和蒸腾特性的变化规律及其对湿地脱氮的影响,从侧面研究湿地植物在湿地脱氮过程中的作用;(2)湿地基质对NH4+-N和TN的吸附净化,以及净化过程中NO3--N的转化规律研究;(3)湿地中脱氮微生物的种群分析研究,结合湿地脱氮效果以MPN-FISH方法对湿地中硝化菌群进行了统计分析;(4)不同植物湿地中溶解氧分布规律研究,以及溶解氧水平对脱氮效果的影响;(5)全面分析研究了湿地构型、水力条件及运行方式等对脱氮效果的影响,最后进行了部分湿地强化脱氮试验。综合试验数据,文章深入探讨了湿地脱氮的机理,分析组成湿地的基质、植物和微生物在脱氮过程中的作用。试验发现,湿地植物的光合作用强度影响湿地整体的脱氮效果,光合代谢总量影响湿地TN的去除量;在所有的湿地植物中,芦苇的光合作用强度较大,水分利用率较高,根系泌氧量大;仅靠湿地基质吸附去除污染物的效果较差,而基质和植物根系及微生物的结合才是湿地脱氮的最佳介质;MPN-FISH分析表明,曝气后湿地硝化菌生长环境得到改善,菌群数量提高;同时借助“灰箱”理论,运用神经网络模型对湿地的运行条件进行优化,并在此基础上提出湿地强化脱氮的可行方法。最后试验以高污染负荷废水为对象,进行强化脱氮试验并加以验证。另外,在考虑高效脱氮的前提下,试验探讨了湿地对磷的去除效果,研究了湿地除磷的机理,对于全面提高湿地脱氮除磷功能具有借鉴意义。本研究结合试验成果探讨了人工湿地的脱氮机理,提出人工湿地高效脱氮运行的适用技术,对于推广人工湿地在不同地区和条件下的应用具有重要意义。更多还原

【Abstract】 When used in wastewater treatment, the constructed wetland own many advantages of good water quality of outlet, low cost of construction and daily operation, convenience of management and aesthetic value, especially is consistent with the latest environmental tendency of diminishing and spreading form in national wastewater treatment, and is worthy of popularizing in small and middling cities. However, the pollutant removal efficiency of constructed wetland is greatly affected by such factors as air temperature, characteristic of filling materials in wetland, wetland plants, microorganisms in soil,the evaporation and transpiration of wetland, however these factors limit the further improving of purifying effect in wetland, now becoming the blocking bottleneck in extending application of wetland.Aiming at the affecting factors of nitrogen removal and using the outlet water of prime sedimentation tank as the inlet water of wetland, during the period of Sept.2002 to April.2005, when the contracted wetland were ran in stable conditions, the relation between nitrogen removal efficiency and its impacting factors was studied through the serial constructed wetland. The following experiments are included:(1) the analysis of nitrogen removal effect of different wetland plant, for the first time, the changing laws of photosynthesis and evapotranspiration wetland plants and relation between laws and nitrogen removal effect were studied in experiment, from another point of view the role of plants in wetland nitrogen removal was studied; (2) the wetland filling materials purified pollutants by NH4+-N and TN absorption, and the transforming laws of NO3--N in the process; (3) nitrifying bacteria community were studied by using method of MPN-FISH and statistical data were collected;(4)the study of DO distribution in different plant wetland and its effects on nitrogen removal were discussed; (5)the impacts of wetland construction form, hydraulic condition and operation condition on nitrogen removal were studied all together, ended with some nitrogen removal intensifying experiments.Integrating the experiment data, the nitrogen removal mechanism was studied in details in the paper, by analyzing the function of filling materials, plants and microorganism in wetland it is demonstrated that the photosynthesis and evapotranspiration intensity of wetland plant have great impacts on the nitrogen removal effect, and the total photosynthesis metabolizing capacity could affect the nitrogen removal quantity; the reed has the highest photosynthesis intensity, water use efficiency and large excreting dissolved oxygen in root area; the combination of them have better nitrogen removal efficiency than single one of them, and which is the optimization medium; it is indicated that the cultivating surrounding of nitrifying bacteria was improved and its number was increased too by MPN-FISH analysis; according the“Grey Box”theory, the operation conditions were optimized by the nerve net model, and on the basis the proper feasible methods of intensifying nitrogen removal were put forward. Finally the intensifying methods were tested when the high pollutant concentration wastewater was treated in wetland. Furthermore the phosphorus removal effect and removal mechanism were studied, which maybe helpful to the improving the nitrogen and phosphorus removal together.The nitrogen removal mechanism was studied by suing the experiment achievements in the paper, and the methods of high nitrogen removal efficiency were put forward, which has significant value in popularizing the application of wetlands in varying areas and conditions.更多还原