【摘要】 基于浅埋深、薄基岩、厚煤层的赋存条件,在我国西部煤矿区往往排出富含有机氮和无机氮(硝酸盐氮、亚硝酸盐氮或氨氮)的矿井水,如果不经过处理就直接排放,会给生态环境带来严重危害。作为实现保水采煤、生态保护的措施之一,地下水库技术已在我国多个西部生态脆弱煤矿区得到了实施,然而有关水质保障及安全运行的研究报道甚少。研究通过矸石柱模拟补连塔矿地下水库的水文地质环境,结合水中TN、"三氮"等理化指标的测试,开展了矿井水中有机氮和"三氮"的迁移转化规律研究。研究结果表明:渗流流量均值0.51 mL/min、1 016 h(12.54个孔隙体积数PV)内,在模拟的水-岩间的缺氧环境中,同时存在有机氮的矿化作用、亚硝酸盐及硝酸盐的反硝化作用。在实验初期的1.19～2.47 PV,有机氮浓度快速下降,而氨氮浓度快速上升,这说明试验初期有机氮的氨化作用较强。之后有机氮的矿化作用逐渐减弱,导致水中氨氮含量逐渐减小并趋于稳定。在矿井水C/N为2.32～3.08的条件下,较强的还原作用导致亚硝酸盐的去除率在99.9%以上、硝酸盐的去除效率在74%～90%。矿井水TN的去除效率在57%～71%,由于淋滤用液硝酸盐含量较低,因此TN的去除主要与亚硝酸盐的减少有关。有机物降解过程低分子量有机酸的生成使得水中H~+含量升高、淋出液pH值始终低于淋滤用液。研究结果可为地下水库技术的有效实施提供水质保障和安全运行方面的借鉴。更多还原

【Abstract】 Based on the occurrence conditions of shallow buried depth,thin bedrock and thick coal seam in western coal mine areas,the contents of organic and inorganic nitrogen（NO₃^--N,NO₂^--N or NH₄⁺-N）in mine water are oftenhigh.If it is directly discharged without treatment,the ecological environment will be damaged seriously.As one of the water-preserved mining and ecological protection measures,groundwater reservoir technology has been implemented in many ecologically fragile coal mining areas in Western China.However,there are few reports on water quality and safe operation during the water storage in a groundwater reservoir.Column experiments were carried out to study the migration and transformation regulation of organic and inorganic nitrogen in the simulated groundwater reservoir packed with coal gangue in Bulianta Coal Mine,combining with the test of total nitrogen（TN）,NO₃^--N,NO₂^--N,NH₄⁺-N and other physicochemical parameters.The results showed that the mineralization of organic nitrogen and denitrification of nitrite and nitrate occurred simultaneously in the simulated anoxic water-rock environment at an average seepage flow rate of 0.51 m L/min during the test duration of 1 016 h（12.54 pore volume）.During 1.19-2.47 PV at the beginning of experiments,the concentration of organic nitrogen in the effluent decreased rapidly while the concentration of ammonia nitrogen increased rapidly,indicating the strengthened ammonification of organic nitrogen at the initial stage of the experiment.Thereafter,the mineralization of organic nitrogen got gradually weakened.Thus the content of ammonia nitrogen in the effluent decreased gradually and tended to be stable.With the ration of organic carbon to nitrogen（C/N）ranging from 2.32 to 3.08 in the studied mine water,the removal efficiencies of nitrate and nitrite were 74%-90% and>99.9%individually,suggesting the strong reduction action.Because of the low nitrate content in the input solution,the removal of TN with the efficiency ranging from 57% to 71%was mainly related to the reduction of nitrite.The formation of organic acids with low molecular weight during the degradation of organic matter,such as ammonification of organic nitrogen,induced the increase of H⁺ in the mine water.Consequently,the pH value in the eluted solution was always lower than that in the input mine water during the column experiment.The findings could provide a theoretical support for the effective implementation of groundwater reservoir technology in terms of water quality assurance and safe operation.更多还原