华北平原制革废水Cr(Ⅲ)和氨氮在典型包气带中迁移模拟与污染评价  

Migration simulation and pollution assessment of Cr(III)and ammonia from tannery wastewater in typical vadose zone in North China Plain

作　　者：庞雅婕 李春辉[3] 韩占涛 张兆吉[4,5] 孔祥科 PANG Yajie;LI Chunhui;HAN Zhantao;ZHANG Zhaoji;KONG Xiangke(School of Water Resources and Environment,Beijing Key Laboratory of Water Resources and Environmental Engineering,and MOE Key Laboratory of Groundwater Circulation and Environmental Evolution,China University of Geosciences(Beijing),Beijing 100083,China;Center for Hydrogeology and Environmental Geology,China Geological Survey,Baoding 071000,Hebei,China;North China University of Water Resources and Electric Power,Zhengzhou 450046,Henan,China;Institute of Hydrogeology&Environmental Geology,Chinese Academy of Geological Sciences,Shijiazhuang 050061,Hebei,China;Key Laboratory of Groundwater Remediation of Hebei Province and China Geological Survey,Shijiazhuang 050061,Hebei,China)

机构地区：[1]中国地质大学(北京)水资源与环境学院/北京市水资源与环境工程重点实验室/地下水循环与环境演化教育部重点实验室,北京100083 [2]中国地质调查局水文地质环境地质调查中心,河北保定071000 [3]华北水利水电大学,河南郑州450046 [4]中国地质科学院水文地质环境地质研究所,河北石家庄050061 [5]中国地质调查局/河北省地下水污染机理与修复重点实验室,河北石家庄050061

出　　处：《中国地质》2024年第4期1280-1289,共10页Geology in China

基　　金：河北省自然科学基金项目(D2020504003)资助。

摘　　要：【研究目的】为探明制革废水中的特征污染物铬(Cr(Ⅲ))和氨氮(NH_(4)^(+)–N)在华北平原典型包气带中的迁移规律,评价其可能产生的土壤与地下水污染风险。【研究方法】采用土柱淋滤实验研究Cr(Ⅲ)和NH_(4)^(+)–N在典型粉土中的吸附和迁移转化特征,结合Hydrus–1D建立的包气带水流和溶质运移模型,模拟预测深0.5 m渗坑中NH_(4)^(+)–N连续入渗状态下通过包气带到达地下水面所需时间及不同深度浓度值的变化规律。【研究结果】在3 cm定水头,污染液(Cr(Ⅲ)20 mg/L,NH_(4)^(+)–N 250 mg/L)定浓度持续淋滤120 d的情况下,Cr(Ⅲ)在土柱中垂向迁移距离小于10 cm,且以残渣态(73%)为主,未检出Cr(VI)。NH_(4)^(+)–N则迁移能力较强,淋滤40 d后即穿透50 cm厚粉土柱。在高含盐量(电导率为10.08 ms/cm)条件下,NH_(4)^(+)–N在粉土中的迁移主要受吸附作用控制,土-水分配系数为25.87 L/kg,未发生硝化作用。持续淋滤150 d时NH_(4)^(+)–N迁移至地下水面(18 m埋深)且浓度超过Ⅲ类地下水质量标准(0.5 mg/L,GB/T 14848–2017),在223 d完全穿透包气带,严重污染地下水。【结论】高含盐量制革废水中Cr(Ⅲ)在粉土中迁移能力较弱,且难以被氧化为Cr(Ⅵ),对地下水威胁较小。NH_(4)^(+)–N则随水流快速迁移至地下水面,严重威胁地下水安全。This paper is the result of environmental geological survey engineering.Objective This study aims to elucidate the migration patterns of characteristic pollutants,i.e.,chromium(Cr(III))and ammonium nitrogen(NH_(4)^(+)–N),from tannery wastewater in the vadose zone of the North China Plain and to assess the potential risks of soil and groundwater contamination.Methods The adsorption and transport characteristics of Cr(III)and NH_(4)^(+)–N in typical silts were examined using soil column leaching experiments.Additionally,the vadose zone water flow and solute transport model established by Hydrus−1D was utilized to simulate and predict the time required for NH_(4)^(+)–N to reach the groundwater table at a depth of 0.5 m under continuous infiltration conditions,along with changes in concentrations at various depths.Results Under a constant head of 3 cm and a pollutant solution concentration(Cr(III)20 mg/L and NH_(4)^(+)–N 250 mg/L)maintained for 120 d,the vertical migration distance of Cr(III)in the soil column was less than 10 cm,predominantly in the residual form(73%),with no detection of Cr(VI).By contrast,NH_(4)^(+)–N exhibited a stronger migration capability,penetrating a 50 cm thick silt column within 40 d.Under high salinity conditions(EC:10.08 ms/cm),the migration of NH_(4)^(+)–N was controlled by adsorption,with a Kd of 25.87 L/kg,and no nitrification occurred.After 150 d of continuous leaching,NH_(4)^(+)–N migrated to the groundwater table(18 m depth)with concentrations exceeding the Class III Groundwater Quality Standard(0.5 mg/L,GB/T 14848–2017).By 223 d,it completely penetrated the vadose zone,severely contaminating the groundwater.Conclusions In high–salinity tannery wastewater,Cr(III)exhibits limited migration capacity in silt and is difficult to oxidize to Cr(VI),posing a lesser threat to groundwater.Conversely,NH_(4)^(+)–N rapidly migrates to the groundwater surface with water flow,posing a serious threat to groundwater safety.

关 键 词：三价铬 氨氮 包气带 迁移 Hydrus–1D 制革废水 华北平原 环境地质调查工程 

分 类 号：X508[环境科学与工程—环境工程] X794X131