【摘要】 为研究 RBF对入渗河水的净化功效 ,利用土柱实验 ,首次研究了非饱和 RBF中氮转化及环境效应。结果表明 :氨氮在非饱和 RBF中主要参与吸附作用与硝化作用。硝化作用强度与氨氮浓度具有相关性 ,作用程度取决于 RBF系统尺度、充氧条件等 ,氨氮的转化可引起系统渗透性能减小、Eh 与 p H值的改变及入渗河水中部分离子浓度的升高等更多还原

【Abstract】 Riverbank filtration （RBF） is widely used in the production of drinking water in many cities in North China, such as Xi’an, Lanzhou, Harbin, Tianjin, etc. But unsaturated RBF is a phenomenon that exists more or less and cannot be completely avoided. Surface water has been polluted widely, and the polluted water may influence the groundwater quality through RBF, so the transformation and degradation of the pollutants during RBF get more and more attention. In this paper, we aim to study the transformation of nitrogen and its environmental effect during the unsaturated RBF, because such knowledge is essential to the protection of groundwater resources and to the purification of polluted water. The sediments and media collected respectively from Kuihe riverbed （located at XuZhou, Jiangsu province） and its bank aquifer were put properly into the soil column of the experimental system. The sediments and media were soaked with tap water for more than half a year to make its state close to the real one, and then the soil column test was carried out. NH⁺₄-N, NO^-₃-N, NO^-₂-N and other indicators were monitored in the test process. During the RBF,Cl^- is a tracer and its concentration was generally considered to obey the dispersion theory in hydrodynamics. Compared with Cl^- concentration, NH⁺₄-N concentration was lower for a short period after test was begun. During that short period, nitrobacter and denitrifier could not have been domesticated, and nitrification and denitrification could not take place, only the adsorption was happening to make NH⁺₄-N accumulated in RBF, and then NH⁺₄-N concentration was smaller in outlet water. It was helpful to nitrification that NH⁺₄-N was accumulated by adsorption. Then NH⁺₄-N, NO^-₃-N, NO^-₂-N concentrations got higher with time until they all stabilized approximately two months after test was begun. It was indicated that NH⁺₄-N was involved in nitrification, based on nitrogen mass balance. The nitrification occurrence was not affected by the concentration of NH⁺₄-N, but its intensity was; its reaction grade was determined by the scale of riverbank filtration system and replenishing of oxygen. And the effects caused by this transformation of nitrogen, found through analyzing the variations of quantity and quality of the outlet water, were that the permeability decreased, E_h and pH varied, and concentrations of several compounds increased. Therefore, NH⁺₄-N in polluted river water causes a secondary pollution of groundwater by unsaturated RBF.更多还原