去除地下水中硝酸盐的渗透性反应墙研究  

Removal of Nitrate from Groundwater Using Permeable Reactive Barrier

作　　者：李秀利[1] 杨君君[1] 卢晓霞[1] 张姝[1] 侯珍[1] 

机构地区：[1]北京大学城市与环境学院,地表过程分析与模拟教育部重点实验室,北京100871

出　　处：《环境科学》2013年第3期914-918,共5页Environmental Science

基　　金：国家自然科学基金项目(40871214,41071311);霍英东教育基金项目(114043)

摘　　要：通过土柱试验模拟地下水环境,研究以发酵树皮和沙子混合物为反应介质的渗透性反应墙(生物墙)对地下水中硝酸盐的去除情况,探讨其作用机制与影响因素,为硝酸盐污染地下水的修复提供经济有效的方法.结果表明,从模拟生物墙运行的第3 d起,墙内为强还原环境(Eh在-100 mV之下),有利于硝酸盐的还原降解.在15 d的运行时间内,模拟生物墙对水中硝态氮(NO3--N)的去除率为80%～90%左右(NO3--N由进水的20 mg·L-1可降至出水的1.6 mg·L-1);出水中亚硝态氮(NO2--N)的浓度较低,一直小于2.5 mg·L-1;出水中铵态氮(NH4+-N)的浓度在前2 d较低,从第3 d起升至12 mg·L-1.模拟生物墙对NO3--N的去除机制主要为吸附和微生物降解.提高模拟生物墙内水流速度后,NO3--N的去除率有所下降,出水中NH4+-N的浓度明显降低.在模拟生物墙下游串联一个模拟沸石墙,可去除水中98%的NH4+-N.To provide a cost-effective method for the remediation of nitrate-polluted groundwater, column experiments were performed to study the removal of nitrate by permeable reactive barrier filled with fermented mulch and sand （biowall） , and the mechanisms and influence factors were explored. The experimental results showed that the environmental condition in the simulated biowall became highly reduced after three days of operation （oxidation-reduction potential was below - 100 mV） , which was favorable for the reduction of nitrate. During the 15 days of operation, the removal rate of nitrate nitrogen （NO3- -N） by the simulated biowall was 80% -90% （NO3- -N was reduced from 20 mg·L^-1 in the inlet water to 1.6 mg·L^-1 in the outlet water） ; the concentration of nitrite nitrogen （ NO2 -N） in the outlet water was below 2.5 mg·L^-1 ; the concentration of ammonium nitrogen （ NH4＋ -N） was low in the first two days but increased to about 12 mg·L^-1 since day three. The major mechanisms involved in the removal of nitrate nitrogen were adsorption and biodegradation. When increasing the water flow velocity in the simulated biowall, the removal rate of NO3- -N was reduced and the concentration of NH4＋ -N in the outlet water was significantly reduced. A simulated zeolite wall was set up following the simulated biowall and 98% of the NH4＋ -N could be removed from the water.

关 键 词：硝酸盐 污染 地下水 生物墙 沸石墙 

分 类 号：X523[环境科学与工程—环境工程]