Fe^(3+)对人工快速渗滤系统脱氮效能的影响

Effect of Fe^(3+) on nitrogen removal efficiency in constructed rapid infiltration system

人工快速渗滤系统(CRI)存在TN去除率低的问题,探寻有效提高CRI系统脱氮效能的方法和技术是目前研究的热点。通过构建CRI污水处理系统,研究了Fe^(3+)在不同添加量下对CRI系统氮素污染物迁移转化及脱氮功能菌分布和活性的影响。结果表明,ρ(Fe^(3+))=2~10 mg·L^(-1)时有利于TN去除,其中ρ(Fe^(3+))=7 mg·L^(-1)时TN去除率最高,比空白对照组提高了30.1%,CRI系统内亚硝酸菌(有氧段)和反硝化菌(饱水段)的数量分别比空白对照组提高3.86、0.42倍,0~80 cm、80~100 cm、100~150 cm段的脱氢酶活性分别为空白对照组的1.68、2.17、1.66倍;当ρ(Fe^(3+))=20 mg·L^(-1)时,硝酸菌和反硝化菌的数量或活性明显下降,过量Fe^(3+)添加对CRI系统脱氮产生抑制效应。

Because the TN removal rate in a constructed rapid infiltration（ CRI） system is low,seeking the methods and technology to improve denitrification efficiency in CRI systems is now a hot research topic. By constructing a CRI wastewater treatment system,the effects of addition of different amounts of Fe^3＋on nitrogen immigration and transformation,as well as the distribution of denitrification microorganisms and their activity,were studied. Results showed that TN removal was improved when Fe^3＋concentration was 2 to 10 mg·L^-1. When the Fe^3＋concentration was 7 mg·L^-1,the TN removal rate increased by 30. 1%（ compared to a blank control group）. The number of nitrite bacteria（ aerobic stage） and denitrifying bacteria（ anoxic stage） in the CRI system was 3. 86 and 0. 42 times higher,respectively,than for the blank control group. The dehydrogenase activity at 0 to 80,80 to 100,and 100 to 150 cm depth was respectively 1. 68,2. 17,and 0. 42 times as much as for the blank control group. When the Fe^3＋concentration was 20 mg·L^-1,the number or activity of nitrite oxidizing and denitrifying bacteria decreased significantly. The excessive Fe^3＋added produced an inhibitory effect on denitrification of the CRI system.