|其他题名: ||NITROGEN REMOVAL EFFICIENY AND MECHANISM IN CONSTTRUTED WETLAND|
2）处理不同类型的废水，湿地的脱氮效率是不同的。处理高碳高氮的农村生活污水（海桥村）的湿地中，NH3-N的的去除率为1.18g/m-2d-1，TN的去除率为1.25g/m-2d-1。处理低碳高氮废水（黑臭河道）时，NH3-N的去除率1.22gNH3-Nm-2•d-1，TN的去除率为1.44g TNm-2•d-1。在处理低碳低氮的污染水（富营养河流）时，湿地对氨氮和总氮的去除率分别为0.123g NH3-Nm-2•d-1和0.169gTNm-2•d-1。因此在借鉴相同纬度与海拔地区的经验时，需要考虑到湿地处理污水的类型和水质特征。
5）限制性曝气在人工湿地中的运用是一低能高效的创新的方法，与传统湿地相比其效率更高、技术经济性能更好，且具有较高的污染物去除率, BOD的去除率16.7 g d-1m-2。氨氮的去除率为4.54g d-1m-2，TN的去除4.99g d-1m-2。而且由于使用土地的减少，建设费用亦会相应的减少。曝气系统的耗电量仅为传统生物接触氧化法的28.8%。|
|英文摘要: ||Constructed wetland is widely used in some regions of China as a kind of technology for municipal wastewater treatment, such as decentralized wastewater, drainge from non-point rural pollution, aquaculture wastewater and some non-toxic industrial wastewater, due to its low cost of construction and operation. Organic matter and suspend solid removal efficiency was normally quite high in the constructed wetlands but low nitrogen removal efficiency remained to be enhanced. Thus, the nitrogen removal efficiency was usually the most focused consideration in design of constructed wetlands. Moreover, the mechanism of nitrogen removal in constructed wetlands was disputed, and the mathematic model of nitrogen removal was difficult to build. Generally, the constructed wetlands were designed according to empirical parameters of the similar wetlands in the same latitude and latitude. Unfortunately，there was only a fat lot empirical parameters about the constructed wetland, so as to employ larger land area by the designers in order to meet the effluent standard, the construction cost increased as a result. In this study, nitrogen efficiency and seasonal variation of three constructed wetlands for three types of wastewater treatment were investgated in order to find the proper parameters for the constructed wetland design. Meanwhile, the mechanisms of nitrogen removal in five constructed wetlands were studied, and the cost-effective aeration constructed wetland hereby was worked over in development.
Main results are shown as the followings:
1) Nitrogen removal efficiency in constructe wetlands varied with season. The removal rate was closely related with temperature. The highest removal rate was found in summer and lowest in winter.
2) Nitrogen removal efficiency in constructe wetlands varied with the types of wastewater on the other hand. In the constructed wetland employed for high carbon and high nitrogen wastewater treatment, the removal rate of ammonia nitrogen was 1.18g/m-2d-1 and the total nitrogen was 1.25g/m-2d-1. In the constructed wetland for low carbon and high nitrogen wastewater treatment, the removal rate of ammonia nitrogen was 1.22g/m-2d-1 and the total nitrogen was 1.44g/m-2d-1. In the constructed wetland for low carbon and low nitrogen wastewater treatment, the removal rate of ammonia nitrogen was 0.123g/m-2d-1 and the total nitrogen was 0.169 g/m-2d-1. Thus, to the types of wastewater must be paid more attention in the constructed wetland design.
3) The constructed wetland nitrogen efficiency was also related to its operation age. Following the constructed wetland ran on the rails, the nitrogen efficiency of the constructed wetland would be enhanced.
4) The mechanisms of nitrogen removal in constructed wetlands were different according to the types of wastewater treated. When the high carbon and high nitrogen wastewater was treated, the nitrogen was removed from the wastewater by the microbial process. 23% nitrogen was removed by partial nitrification and denitrification, 77% nitrogen was removed by classic nitrification and denitrification. When the low carbon and high nitrogen wastewater was treated, 50% nitrogen was removed from wastewater in the Laoduanpu constructed wetland by partial nitrification and denitrification, and 20% nitrogen was removed from wastewater in the Beixia constructed wetland by the “novel” process. When the low carbon and low nitrogen wastewater was treated, 23%, 18% and 21% nitrogen were removed from the wastewater by the process of volatilization, plant uptake and microbial process respectively.
5) Limited aeration in the operation of constructed wetland was a cost-effective method. Compared to the traditional wetland, it was more economical and with higher pollutant removal efficiency. The BOD removal rate was 16.7g d-1m-2, the ammonium nitrogen was 4.54g d-1m-2, and the total nitrogen was 4.99 g d-1m-2. Due to less land area was used, less construction cost was needed accordingly. The electricity consumption of limited aeration system accounted for only 28.8% of the traditional biological oxidation process consumed.|
|Appears in Collections:||中科院水生所知识产出（2009年前）_学位论文|
|File Name/ File Size