深层地下水中硝酸盐迁移转化的实验模拟研究
|
摘要
以新近系明化镇组热储层细砂为岩土介质,在35℃、q为0.8 cm/h条件下,分别以氯离子和硝酸盐作为示踪剂开展室内土柱模拟实验,并采用CXTFIT2.1软件进行数据拟合,研究了硝酸盐运移参数和迁移转化机制。研究结果表明:在模拟的松散孔隙型热储层中,硝酸盐的迁移转化遵循一级衰减动力学假设的溶质对流-弥散模型,其衰减系数拟合值k_1为0.019 h~(-1),纵向弥散系数D为3.401 cm~2/h。实验期间,硝酸盐转化为亚硝酸盐、氨氮的最大比率分别为25.4%、4.37%。亚硝酸盐、氨氮的富集与低的C/N、实验初期亚硝酸盐还原菌的缺乏及水-岩体系p H值有关。实验期间淋出液p H值缓慢下降,ORP下降较快。硝酸盐、亚硝酸盐、EC及TDS变化趋势一致:均为在硝酸盐穿透阶段快速增加、中后期趋于稳定,这说明随着时间的推移,水-岩系统已形成了较稳定的微生物体系,导致硝酸盐转化速率及产物都趋于稳定,并且EC和TDS线性相关。
The chloride and nitrate displacement experiments were carried out at 35℃at an average Darcy’s flux of 0.8 cm/h,respectively,in a loose-pore geothermal reservoir matrix which was composed of Minghuazhen Formation in Neogene period.Then the computer code CXTFIT was used to fit the experimental data and to determine the transport parameters.The results showed that the assumption of first-order reaction kinetics in convection-dispersion equation(CDE)resulted in a close agreement between the model results and the data.The simulated values of the first-order decay coefficient(k_1)and longitudinal dispersion coefficient(D)at an average Darcy’s flux of 0.8 cm/h were 0.019 h~(-1)and 3.401 cm~2/h,respectively.The maximum conversion efficiencies for the products of nitrite and ammonium were 25.4%,4.37%,respectively.The obvious accumulation of nitrite and ammonium was correlated with the low value of C/N,insufficiency of nitrite reduction bacteria and p H in the simulated geothermal water.The effluent p H decreased slowly while the ORP decreased quickly with time.Meanwhile,the values of nitrate,nitrite,ammonium,EC and TDS increased quickly during the nitrate breakthrough period in the simulated column and tended to be constant with time,which indicated that the stable microbial environment was formed in the simulated column with time.And EC was linearly correlated with TDS.
The chloride and nitrate displacement experiments were carried out at 35℃at an average Darcy’s flux of 0.8 cm/h,respectively,in a loose-pore geothermal reservoir matrix which was composed of Minghuazhen Formation in Neogene period.Then the computer code CXTFIT was used to fit the experimental data and to determine the transport parameters.The results showed that the assumption of first-order reaction kinetics in convection-dispersion equation(CDE)resulted in a close agreement between the model results and the data.The simulated values of the first-order decay coefficient(k_1)and longitudinal dispersion coefficient(D)at an average Darcy’s flux of 0.8 cm/h were 0.019 h~(-1)and 3.401 cm~2/h,respectively.The maximum conversion efficiencies for the products of nitrite and ammonium were 25.4%,4.37%,respectively.The obvious accumulation of nitrite and ammonium was correlated with the low value of C/N,insufficiency of nitrite reduction bacteria and p H in the simulated geothermal water.The effluent p H decreased slowly while the ORP decreased quickly with time.Meanwhile,the values of nitrate,nitrite,ammonium,EC and TDS increased quickly during the nitrate breakthrough period in the simulated column and tended to be constant with time,which indicated that the stable microbial environment was formed in the simulated column with time.And EC was linearly correlated with TDS.
引文
[1]刘花台,郭占荣.深层地下水及其可利用性分析[J].水文地质工程地质,2008,35(3):124-128.Liu Huatai,Guo Zhanrong.An analysis of deep groundwater and its utilization[J].Hydrogeology and Engineering Geology,2008,35(3):124-128.
[2]Wang Xinyi,Zhao Li,Liu Xiaoman,et al.Temperature effect on the transport of nitrate and ammonium ions in a loose-pore geothermal reservoir[J].Journal of Geochemical Exploration,2013,124:59-66.
[3]张庆,赵丽,王心义.NH4+在孔隙型地热水中的运移机制研究[J].环境科学与技术,2015,38(4):74-78.Zhang Qing,Zhao Li,Wang Xinyi.Study on the transportation mechanism of NH4+in the porous geothermal water[J].Environmental Science&Technology,2015,38(4):74-78.
[4]Jellali S,Diamantopoulos E,Kallali H.Dynamic sorption of ammonium by sandy soil in fixed bed columns:evaluation of equilibrium and non-equilibrium transport processes[J].Journal of Environmental Management,2010,91:897-905.
[5]杨汉培,张颖,戴开静,等.河道湿地干湿运行模式下铵氮的迁移转化研究[J].水利学报,2011,42(12):1407-1415.Yang Hanpei,Zhang Ying,Dai Kaijing,et al.Transformation of ammonium nitrogen in riverine wetland under regular alternative flooding and draining[J].Journal of Hydraulic Engineering,2011,42(12):1407-1415.
[6]张沙莎,靳孟贵,孙强,等.干湿交替条件下包气带土柱中氮素迁移转化规律实验[J].地学前缘,2010,17(6):52-58.Zhang Shasha,Jin Menggui,Sun Qiang,et al.Experiment on the transformation of nitrogen in variably saturated soil column under alternative leaching and drying conditions[J].Earth Science Frontiers,2010,17(6):52-58.
[7]李绪谦,朱雅宁,于光,等.氨氮在弱透水层中的渗透迁移规律研究[J].水文,2011,31(3):71-75.Li Xuqian,Zhu Yaning,Yu Guang,et al.Study on permeation and migration law of ammonia nitrogen in aquitard[J].Hydrology,2011,31(3):71-75.
[8]Chun J A,Cooke R A,Eheart J W,et al.Estimation of flow and transport parameters for woodchip-based bioreactors:I.laboratory-scale bioreactor[J].Biosystems Engineering,2009,104:384-395.
[9]Tesoriero A J,Liebscher H,Cox S E.Mechanism and rate of denitrification in an agricultural watershed:electron and mass balance along groundwater flow paths[J].Water Resources Research,2000,36(6):1545-1559.
[10]李绪谦,谢雪,李红艳,等.p H值对弱透水层中硝态氮迁移转化的影响[J].水资源保护,2011,27(1):67-72.Li Xuqian,Xie Xue,Li Hongyan,et al.p H impact on nitrate migration and transformation in the aquitard[J].Water Resources Protection,2011,27(1):67-72.
[11]de Catanzaro J B,Beauchamp E G,Drury C F.Denitrification vs.dissimilatory nitrate reduction in soil with alfalfa,straw,glucose and sulfide treatments[J].Soil Biology and Biochemistry,1987,19:583-587.
[12]吴丰昌,王立英,黎文,等.天然有机质及其在地表环境中的重要性[J].湖泊科学,2008,20(1):1-12.Wu Fengchang,Wang Liying,Li Wen,et al.Natural organic matter and its significance in terrestrial surface environment[J].Journal of Lake Sciences,2008,20(1):1-12.
[13]Anu Matilainen,Egil T Gjessing,Tanja Lahtinen,et al.An overview of the methods used in the characterisation of natural organic matter(NOM)in relation to drinking water treatment[J].Chemosphere,2011,83:1431-1442.
[14]任南琪,王爱杰,赵阳国.废水厌氧处理硫酸盐还原菌生态学[M].北京:科学出版社,2009.Ren Nanqi,Wang Aijie,Zhao Yangguo.Ecology of Sulfate Reducing Bacteria in Anaerobic Wastewater Treatment[M].Beijing:Science Press,2009.
[15]张云,张胜,刘长礼,等.包气带土层防护地下水污染的反硝化测定影响综述[J].水文地质工程地质,2010,37(2):114-119.Zhang Yun,Zhang Sheng,Liu Changli,et al.A review of influence of denitrification measurement in soil layers of aeration zone aimed at groundwater protection[J].Hydrogeology and Engineering Geology,2010,37(2):114-119.
[2]Wang Xinyi,Zhao Li,Liu Xiaoman,et al.Temperature effect on the transport of nitrate and ammonium ions in a loose-pore geothermal reservoir[J].Journal of Geochemical Exploration,2013,124:59-66.
[3]张庆,赵丽,王心义.NH4+在孔隙型地热水中的运移机制研究[J].环境科学与技术,2015,38(4):74-78.Zhang Qing,Zhao Li,Wang Xinyi.Study on the transportation mechanism of NH4+in the porous geothermal water[J].Environmental Science&Technology,2015,38(4):74-78.
[4]Jellali S,Diamantopoulos E,Kallali H.Dynamic sorption of ammonium by sandy soil in fixed bed columns:evaluation of equilibrium and non-equilibrium transport processes[J].Journal of Environmental Management,2010,91:897-905.
[5]杨汉培,张颖,戴开静,等.河道湿地干湿运行模式下铵氮的迁移转化研究[J].水利学报,2011,42(12):1407-1415.Yang Hanpei,Zhang Ying,Dai Kaijing,et al.Transformation of ammonium nitrogen in riverine wetland under regular alternative flooding and draining[J].Journal of Hydraulic Engineering,2011,42(12):1407-1415.
[6]张沙莎,靳孟贵,孙强,等.干湿交替条件下包气带土柱中氮素迁移转化规律实验[J].地学前缘,2010,17(6):52-58.Zhang Shasha,Jin Menggui,Sun Qiang,et al.Experiment on the transformation of nitrogen in variably saturated soil column under alternative leaching and drying conditions[J].Earth Science Frontiers,2010,17(6):52-58.
[7]李绪谦,朱雅宁,于光,等.氨氮在弱透水层中的渗透迁移规律研究[J].水文,2011,31(3):71-75.Li Xuqian,Zhu Yaning,Yu Guang,et al.Study on permeation and migration law of ammonia nitrogen in aquitard[J].Hydrology,2011,31(3):71-75.
[8]Chun J A,Cooke R A,Eheart J W,et al.Estimation of flow and transport parameters for woodchip-based bioreactors:I.laboratory-scale bioreactor[J].Biosystems Engineering,2009,104:384-395.
[9]Tesoriero A J,Liebscher H,Cox S E.Mechanism and rate of denitrification in an agricultural watershed:electron and mass balance along groundwater flow paths[J].Water Resources Research,2000,36(6):1545-1559.
[10]李绪谦,谢雪,李红艳,等.p H值对弱透水层中硝态氮迁移转化的影响[J].水资源保护,2011,27(1):67-72.Li Xuqian,Xie Xue,Li Hongyan,et al.p H impact on nitrate migration and transformation in the aquitard[J].Water Resources Protection,2011,27(1):67-72.
[11]de Catanzaro J B,Beauchamp E G,Drury C F.Denitrification vs.dissimilatory nitrate reduction in soil with alfalfa,straw,glucose and sulfide treatments[J].Soil Biology and Biochemistry,1987,19:583-587.
[12]吴丰昌,王立英,黎文,等.天然有机质及其在地表环境中的重要性[J].湖泊科学,2008,20(1):1-12.Wu Fengchang,Wang Liying,Li Wen,et al.Natural organic matter and its significance in terrestrial surface environment[J].Journal of Lake Sciences,2008,20(1):1-12.
[13]Anu Matilainen,Egil T Gjessing,Tanja Lahtinen,et al.An overview of the methods used in the characterisation of natural organic matter(NOM)in relation to drinking water treatment[J].Chemosphere,2011,83:1431-1442.
[14]任南琪,王爱杰,赵阳国.废水厌氧处理硫酸盐还原菌生态学[M].北京:科学出版社,2009.Ren Nanqi,Wang Aijie,Zhao Yangguo.Ecology of Sulfate Reducing Bacteria in Anaerobic Wastewater Treatment[M].Beijing:Science Press,2009.
[15]张云,张胜,刘长礼,等.包气带土层防护地下水污染的反硝化测定影响综述[J].水文地质工程地质,2010,37(2):114-119.Zhang Yun,Zhang Sheng,Liu Changli,et al.A review of influence of denitrification measurement in soil layers of aeration zone aimed at groundwater protection[J].Hydrogeology and Engineering Geology,2010,37(2):114-119.