不同补水方式下砂壤土渗滤系统对硝态氮去除效果

发布时间：2018-05-16 20:51

  本文选题：温度 + 反硝化　； 参考：《农业工程学报》2017年08期

【摘要】：在水资源短缺的北京地区利用再生水回补城市河湖,一方面对于水资源的可持续利用有着十分重要的作用,另一方面也可能带来地下水环境的潜在污染风险。该文采用100 cm砂壤土柱模拟(河湖岸底)土地渗滤系统,设置定水头淹水、交替淹水落干、定流速补水和侧向补水4种不同再生水回补方式,研究再生水中硝态氮(NO_3-N)在土地渗滤系统中的去除效果和迁移转化规律。结果表明,当水力负荷在0.25~2.65 cm/d范围内时,渗滤系统对NO_3-N的去除率随着水力负荷的增大而减小;侧向补水方式下渗滤系统对NO_3-N的去除效果最优,平均去除率高达96.1%。在定水头淹水和侧向补水方式下,系统对NO_3-N的去除主要发生在土柱的上部,而交替淹水落干和定流速补水条件下,土柱中下部对NO_3-N也有一定的去除作用。渗滤系统对NO_3-N的去除主要取决于系统内部微生物的分布情况,土层中的反硝化细菌数量越大,该土层对NO_3-N的去除率就越高。当水温在15~32℃范围内变化时,定水头淹水和交替淹水落干补水方式下,系统对NO_3-N的去除率与温度分别呈指数和幂函数关系。该研究表明土地渗滤系统可实现再生水的进一步净化处理,可为再生水安全回补河湖提供参考。
[Abstract]:In Beijing, where water resources are short, reclaimed water can be used to replenish urban rivers and lakes. On the one hand, it plays an important role in the sustainable utilization of water resources, on the other hand, it may bring potential pollution risk to groundwater environment. In this paper, a 100 cm sandy loam column is used to simulate the land leachate system. Four different reclaimed water recharge methods are set up, such as constant head flooding, alternate flooding, constant flow rate and lateral rehydration. The removal efficiency and migration and transformation of NO3-N in regenerated water in soil leachate system were studied. The results show that when the hydraulic load is within the range of 0.25 ~ 2.65 cm/d, the removal rate of NO_3-N decreases with the increase of hydraulic load, and the average removal rate of NO_3-N is up to 96.1% under the lateral recharge mode. Under the condition of constant head flooding and lateral rehydration, the removal of NO_3-N mainly occurs in the upper part of the soil column, while under the condition of alternate flooding and constant flow rate, the NO_3-N is also removed from the middle and lower part of the soil column. The removal of NO_3-N by leachate system mainly depends on the distribution of microbes in the system. The larger the number of denitrifying bacteria in soil layer, the higher the removal rate of NO_3-N in the soil layer. When the water temperature varies in the range of 1532 鈩，

本文编号：1898352