摘要
以郑州市西南沟壑内出露的新近系明化镇组细砂为多孔介质,在20~60℃的低温范围内,用铵氮作为示踪剂开展室内土柱模拟实验,分别研究2.09~2.39cm/h以及0.003 4cm/h（接近于0）达西流速时铵氮的迁移转化机制和运移参数。研究结果表明：双点位吸附溶质运移模型能较好地表征铵氮的运移机制,与20℃相比,40℃的低温地热水中铵氮更易进入水中影响水质;穿透实验过程中水样的Eh缓慢下降,pH值逐渐上升,硝化反应不明显;当达西流速接近于0（0.003 4cm/h）时,水样氧化还原电位（Eh）在40,60℃下降较明显,硝化反应速率随温度的升高而增加,并且温度越高水样pH值下降越明显,这与硝化反应生成H＋及反应速率有关;水样的溶解性总固体（TDS）含量和电导率（EC）值在铵氮的迁移转化过程中都逐渐升高,这与岩样中矿物质的溶解及硝化反应产物的生成有关;由铵氮的硝化反应引起地热水中亚硝酸盐升高的几率很小。
The study of the transportation and transformation law of ammonia nitrogen in the in-depth pore geothermal water was engaged in.For our research purpose,the column experiments of ammonia nitrogen at temperatures between 20℃and 60℃in the loose-pore geothermal reservoir matrix were carried out,which was formulated in the Neogene Period in Minghuazhen Formation,Henan province.The transportation mechanism and transport parameters of ammonium were studied at Darcy’s fluxes between 2.09cm/h and2.39cm/h at 20℃and 40℃,respectively.Then the transformation law of ammonium in the studied matrix was studied at a Darcy’s flux of 0.003 4cm/h.The results showed that the two-site nonequilibrium transport model fitted the observed breakthrough curve of ammonium well.Because of the the lower adsorption capacity of NH＋4onto the porous media at higher temperature,the geothermal water quality was more easily affected by ammonium at 40℃than that at 20℃during its transport through the matrix.The values of Eh for the simulated geothermal water samples decreased slowly,while the values of pH increased gradually with time during the ammonium displacement experiments at 20℃and 40℃.And the nitrification could be neglected at this stage.When the Darcy’s flux decreased to 0.003 4cm/h,the nitrification efficiency increased with the increasing of temperature,indicated by the obvious decreasing of Eh.Because of the production of H＋during nitrification,pH values for the simulated water samples decreased with time.Moreover,the higher the temperature,the faster the pH values decreased.The values of total dissolved solids（TDS）and electrical conductivity（EC）increased gradually during the ammonium transport and transformation processes,which were related to the dissolution of mineral composition in the matrix and productions of nitrification.The production of nitrite could be neglected during the nitrification of ammonium in the simulated column experiments.
出处
《水土保持学报》
CSCD
北大核心
2014年第5期100-104,共5页
Journal of Soil and Water Conservation
基金
国家自然科学基金项目(41272250)
河南省教育厅科学技术研究重点项目指导计划项目(13B610039)
河南理工大学博士基金项目(B2014-074)
关键词
低温地热水
铵氮
阻滞系数
硝化反应
迁移转化
low-temperature geothermal water
ammonia nitrogen
retardation factor
nitrification
transportation and transformation
