Hendry M Jim, Barbour S Lee, Schmeling Erin E, Wassenaar Leonard I, Shaw Shannon, Schabert Marcie S
Department of Geological Sciences, University of Saskatchewan, 114 Science Place, Saskatoon, SK S7N 5E2, Canada.
Department of Civil and Geological Engineering, University of Saskatchewan, 57 Campus Drive, Saskatoon, SK S7N 5A9, Canada.
Sci Total Environ. 2023 Jan 1;854:158762. doi: 10.1016/j.scitotenv.2022.158762. Epub 2022 Sep 17.
Nitrate (NO-) in mine waste rock derived from undetonated NHNO can contaminate receiving waters. An in-situ bioremediation experiment was conducted at a coal mining operation in Elk Valley, British Columbia, Canada to remediate NO- from large volumes of mine water. Over the test period (201 d), 5000 to 7500 m d of NO--rich (mean concentration 22 mg N L) mine water was injected into saturated waste rock along with methanol, nutrients, and a conservative tracer (Br-). Complete denitrification (<0.5 mg N L) was recorded in monitoring wells located 38 m from the injection wells after 114 to 141 d of operation. Plots of δN- and δO-NO- versus NO--N concentrations for monitoring wells yielded isotopic enrichment factors (ε) for δN- and δO-NO- of -25.7 and -13.2 ‰ for high C/C NO- concentrations (>10.5 mg N L) and -5.5 and -3.6 ‰ for lower C/C values. The fraction of NO denitrified (Dp) calculated using bi-linear ε values for δN- and δO reproduced the Dp determined independently using a conservative tracer indicating that stable isotope tracers of the NO- reducing processes in bioremediation are invaluable to determine Dp. Based on the success of this ongoing bioremediation experiment, the technology is being applied at other sites.
未引爆的硝酸铵产生的矿山废石中的硝酸盐（NO⁻）会污染受纳水体。在加拿大不列颠哥伦比亚省埃尔克谷的一个煤矿作业区进行了一项原位生物修复实验，以去除大量矿井水中的NO⁻。在测试期间（201天），将5000至7500立方米/天的富含NO⁻（平均浓度22毫克氮/升）的矿井水与甲醇、营养物质和一种保守示踪剂（Br⁻）一起注入饱和废石中。运行114至141天后，在距注入井38米处的监测井中记录到完全反硝化（<0.5毫克氮/升）。监测井中δ¹⁵N-NO₃⁻和δ¹⁸O-NO₃⁻与NO₃⁻-N浓度的关系图得出，对于高C/C NO₃⁻浓度（>10.5毫克氮/升），δ¹⁵N-NO₃⁻和δ¹⁸O-NO₃⁻的同位素富集因子（ε）分别为-25.7‰和-13.2‰，对于较低的C/C值，分别为-5.5‰和-3.6‰。使用δ¹⁵N-NO₃⁻和δ¹⁸O的双线性ε值计算的NO₃⁻反硝化分数（Dp）与使用保守示踪剂独立确定的Dp一致，这表明生物修复中NO₃⁻还原过程的稳定同位素示踪剂对于确定Dp非常重要。基于这项正在进行的生物修复实验的成功，该技术正在其他场地应用。
