Nitrate Removal from Groundwater Using a Denitrification Wall Amended with Sawdust: Field Trial
Nitrate Removal from Groundwater Using a Denitrification Wall Amended with Sawdust: Field Trial
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使用木屑改良的反硝化墙去除地下水中的硝酸盐：现场试验
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
M. Vojvodic
中科院分区：
文献类型：
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作者：
L. Schipper;M. Vojvodic
地下水的硝酸盐(NO3)污染会造成受纳水源的污染。我们研究了反硝化墙从浅层地下水中去除硝酸盐的机理。反硝化墙是通过挖掘一条长35米、深1.5米、宽1.5米的截流地下水的沟渠来建造的。将挖掘出的土壤与木屑(30%v/v)混合作为碳源，然后返回到沟中。我们评估了1年内墙内硝酸盐的去除和反硝化作用。地下水中NO3的进入浓度在5-16 mg N-L-1之间，但在反硝化墙中降至-lt；2 mg N L-1。围墙中的全N在当年呈下降趋势，说明N的固定化并不是NO3的一个大的汇。反硝化酶活性(DEA)在运行6mo时达到最大值906 ng Ng-1h-1，说明反硝化作用是NO3去除的重要机制。计算了3.6g Nm~(-3)d~(-1)的最大反硝化速率。底物改良法试验表明，围墙内的反硝化作用主要受NO3浓度的限制，而不受C的限制。在研究过程中，全C没有显着下降(P<；0.05)，但剩余C的有效性下降。尽管有所下降，但DEA和微生物生物量在最后6个月期间保持稳定。研究表明，反硝化墙能有效去除地下水中的硝酸盐，从而保护受纳水。
Nitrate (NO 3 ) contamination of groundwater can cause pollution of receiving waters. We examined the mechanisms by which a denitrification wall removed NO 3 from shallow groundwater. The denitrification wall was constructed by digging a trench (35 m long, 1.5 m deep, and 1.5 m wide) that intercepted groundwater. The excavated soil was mixed with sawdust (30% v/v) as a C source then returned to the trench. We assessed NO 3 removal and denitrification in the wall for 1 yr. Incoming concentrations of NO 3 in groundwater ranged from 5 to 16 mg of N L -1 but these decreased to <2 mg N L -1 in the denitrification wall. Total N in the wall declined during the year demonstrating that N immobilization was not a large sink for NO 3 . Denitrifying enzyme activity (DEA) reached a maximum of 906 ng of N g -1 h -1 after 6 mo of operation, indicating that denitrification was an important mechanism for NO 3 removal. We calculated a maximum rate of NO 3 removal by denitrification of 3.6 g N m -3 d -1 . Substrate-amendment experiments showed that denitrification in the wall was primarily limited by NO 3 concentration and not C. During the study there was no significant decrease (P < 0.05) in total C but the availability of the remaining C declined. Despite this decrease, the DEA and microbial biomass were stable during the last 6 mo. This study demonstrated that denitrification walls can effectively remove NO 3 from groundwater thereby protecting receiving waters.