In Situ Stimulation of Groundwater Denitrification with Formate To Remediate Nitrate Contamination

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• 作者：Richard L. Smith ; Daniel N. Miller ; Myron H. Brooks ; Mark A. Widdowson ; and Marc W. Killingstad
• 刊名：Environmental Science & Technology
• 出版年：2001
• 出版时间：January 1, 2001
• 年：2001
• 卷：35
• 期：1
• 页码：196 - 203
• 全文大小：152K
• 年卷期：v.35,no.1(January 1, 2001)
• ISSN：1520-5851

文摘

In situ stimulation of denitrification has been proposed asa mechanism to remediate groundwater nitrate contamination. In this study, sodium formate was added to a sandand gravel aquifer on Cape Cod, MA, to test whetherformate could serve as a potential electron donor forsubsurface denitrification. During 16- and 10-day trials,groundwater from an anoxic nitrate-containing zone (0.5-1.5 mM) was continuously withdrawn, amended withformate and bromide, and pumped back into the aquifer.Concentrations of groundwater constituents were monitoredin multilevel samplers after up to 15 m of transport bynatural gradient flow. Nitrate and formate concentrationswere decreased 80-100% and 60-70%, respectively,with time and subsequent travel distance, while nitriteconcentrations inversely increased. The field experimentbreakthrough curves were simulated with a two-dimensionalsite-specific model that included transport, denitrification,and microbial growth. Initial values for model parameterswere obtained from laboratory incubations with aquifer corematerial and then refined to fit field breakthrough curves.The model and the lab results indicated that formate-enhanced nitrite reduction was nearly 4-fold slower thannitrate reduction, but in the lab, nitrite was completelyconsumed with sufficient exposure time. Results of this studysuggest that a long-term injection of formate is necessaryto test the remediation potential of this approach fornitrate contamination and that adaptation to nitriteaccumulation will be a key determinative factor.