Study on the transport law of characteristic pollutants in red mud leachate in saturated sand
-
摘要:
为揭示赤泥对地下水的污染机理,防控其污染,对中国北方某炼铝厂赤泥堆场所取淋滤液进行水质分析,识别出严重超标特征污染物F−、SO4 2−、Al3+,通过一维砂柱试验研究了其在饱和中砂、细砂、粉砂3种介质中的运移规律。结果表明:特征污染物在砂柱中运移距离越大,其浓度越小;砂粒粒径越小,渗透系数越小,对特征污染物的截留能力越强,特征污染物在砂柱中完全穿透时间也越长。运用Hydrus-1D软件对3种特征污染物在饱和砂土中的运移过程进行模拟,得出在3种介质中弥散度(α)分别为1.76、0.95、0.58 cm,3种介质中F−的溶质反应参数Kd和Nu分别为2.10、1.00、4.10 mg/mL和24、28、30 mL/mg,SO4 2−的Kd和Nu分别为1.78、0.99、5.00 mg/mL和12、20、32 mL/mg,Al3+的Kd和Nu分别为1.44、1.65、4.44 mg/mL和18、17、45 mL/mg,呈现介质颗粒越细,Kd越大(吸附能力越强),Nu越大(吸附速度越快)的特征。为防止赤泥污染,根据经济适用、取材方便的原则,建议选用粉砂土或颗粒更细的黏土作为污染防渗层。
Abstract:In order to reveal the pollution mechanism of red mud to groundwater and prevent the pollution, the water quality of leachate from a red mud pile site of an aluminium refinery in northern China was analyzed. Three characteristic pollutants severely exceeding standards were identified: F−, SO4 2−, Al3+. Through a one-dimensional sand column experiment, the migration law of the characteristic pollutions in saturated medium sand, fine sand and silt sand was studied. The results showed that the greater the migration distance of characteristic pollutants in the sand column, the smaller the concentration of the pollutants; the smaller the sand particle size, the smaller the permeability coefficient, which means the stronger retention capacity of pollutants and the longer complete penetration time of characteristic pollutants in the sand column. Using Hydrus-1D software to simulate the migration process of the three characteristic pollutants in saturated sand, the dispersion degree (
$\alpha$ ) of the medium sand, fine sand and silty sand was 1.76, 0.95 and 0.58 cm, respectively. The solute reaction parameters Kd and Nu of F− in the three different sands were 2.10, 1.00, 4.10 mg/mL and 24, 28, 30 mL/mg; SO4 2− were 1.78, 0.99, 5.00 mg/mL and 12, 20, 32 mL/mg; Al3+ were 1.44, 1.65, 4.44 mg/mL and 18, 17, 45 mL/mg, respectively. It was displayed that the smaller the grain of sand, the stronger the adsorption capacity (larger Kd) and the faster the adsorption speed (larger Nu). In order to prevent the pollution of red mud, it was recommended to use silt soil or finer-grained clay as the pollution impermeable layer according to the principle of economy and convenience.-
Key words:
- red mud leachate /
- characteristic pollutants /
- saturated sand /
- transport law /
- pollution prevention
-
表 1 3种砂土的土壤水力特征参数
Table 1. Soil hydraulic characteristic parameters of three sandy soils
砂土
类型残留含
水率(θr)/
(cm3/cm3)饱和含
水率(θs)/
(cm3/cm3)经验常数
(γ)/cm−1孔径分布
参数(n)渗透系数/
(cm/min)中砂 0.046 5 0.387 7 0.036 7 2.996 5 0.47 细砂 0.059 0 0.379 3 0.028 0 2.659 6 0.24 粉砂 0.077 9 0.350 4 0.007 7 1.684 5 0.06 表 2 Na+穿透曲线参数反演结果
Table 2. Parameter inversion results of Na+ penetration curve
砂土类型 α实测值/cm 反演前R2 α反演值/cm 反演后R2 中砂 1.72 0.981 1.76 0.990 细砂 1.03 0.980 0.95 0.990 粉砂 0.62 0.979 0.58 0.998 表 3 溶质吸附参数反演结果
Table 3. Solute adsorption parameters inversion results
污染物 参数 中砂 细砂 粉砂 F- Kd//(mg/mL) 1.00 2.10 4.10 Nu/(mL/mg) 28 24 30 R2 0.991 0.992 0.990 SO4 2− Kd//(mg/mL) 0.99 1.78 5.00 Nu/(mL/mg) 20 28 32 R2 0.994 0.993 0.992 Al3+ Kd//(mg/mL) 1.65 2.30 4.44 Nu/(mL/mg) 17 20 45 R2 0.966 0.960 0.975 表 4 污染物穿透厚度随污染时长变化
Table 4. Tab.4 Pollutant penetration thickness under different pollution duration
模拟时长/a 不同污染物穿透厚度/m F− SO4 2− Al3+ 4 1.7 1.5 1.5 8 2.5 2.2 2.2 12 3.2 2.8 2.8 16 3.8 3.3 3.4 20 4.4 3.9 3.9 -
[1] 曲永新, 关文章, 张永双, 等.炼铝工业固体废料(赤泥)的物质组成与工程特性及其防治利用研究[J]. 工程地质学报,2000,8(3):296-305. doi: 10.3969/j.issn.1004-9665.2000.03.008QU Y X, GUAN W Z, ZHANG Y S, et al. Study on material composition and engineering properties, prevention and application of the solid waste (red mud) in aluminium industry[J]. Journal of Engineering Geology,2000,8(3):296-305. doi: 10.3969/j.issn.1004-9665.2000.03.008 [2] 郭书海, 高鹏, 吴波, 等.我国重点氟污染行业排放清单与土壤氟浓度估算[J]. 应用生态学报,2019,30(1):1-9.GUO S H, GAO P, WU B, et al. Fluorine emission list of China's key industries and soil fluorine concentration estimation[J]. Chinese Journal of Applied Ecology,2019,30(1):1-9. [3] 袁霄梅, 王冰莹, 原学政, 等.赤泥中氟迁移转化的影响因素分析[J]. 中国岩溶,2010,29(3):319-324. doi: 10.3969/j.issn.1001-4810.2010.03.015YUAN X M, WANG B Y, YUAN X Z, et al. Analysis on the influence factors to fluorine transfer in red mud[J]. Carsologica Sinica,2010,29(3):319-324. doi: 10.3969/j.issn.1001-4810.2010.03.015 [4] HE L L, TU C L, HE S Y, et al. Fluorine enrichment of vegetables and soil around an abandoned aluminium plant and its risk to human health[J]. Environmental Geochemistry and Health,2021,43(3):1137-1154. doi: 10.1007/s10653-020-00568-5 [5] ABDUL-WAHAB S, ALSUBHI Z. Modeling and analysis of hydrogen fluoride pollution from an aluminum smelter located in Oman[J]. Sustainable Cities and Society,2019,51:101802. doi: 10.1016/j.scs.2019.101802 [6] BEHROOZI A, ARORA M, FLETCHER T D, et al. Sorption and transport behavior of zinc in the soil: implications for stormwater management[J]. Geoderma,2020,367:114243. doi: 10.1016/j.geoderma.2020.114243 [7] de SOUZA A L, MATSURA E E, de MIRANDA J H, et al. Adjustment of soil solute transport paramenters with Matlab 6.5[J]. Engineering Agriculture,2011,31(6):1064-1074. [8] AYOOB S, GUPTA A K. Fluoride in drinking water: a review on the status and stress effects[J]. Critical Reviews in Environmental Science and Technology,2006,36(6):433-487. doi: 10.1080/10643380600678112 [9] 胡鹏, 朱国荣, 王倩, 等.尾矿库淋滤液中氟垂向迁移的土柱淋滤试验[J]. 南京大学学报(自然科学版),2011,47(6):744-750.HU P, ZHU G R, WANG Q, et al. Column leaching tests for modeling vertical migration of fluorine contamination in tailings pond[J]. Journal of Nanjing University (Natural Sciences),2011,47(6):744-750. [10] LIU G J, ZHENG L G, QI C C, et al. Environmental geochemistry and health of fluorine in Chinese coals[J]. Environmental Geology,2007,52(7):1307-1313. doi: 10.1007/s00254-006-0569-6 [11] 张小茅, 周俊, 熊小锋, 等.地下水环境影响评价中污染物运移模拟软件的适宜性评估[J]. 环境科学研究,2019,32(1):10-16.ZHANG X M, ZHOU J, XIONG X F, et al. Evaluation of contaminant transport modeling software for groundwater environmental impact assessment[J]. Research of Environmental Sciences,2019,32(1):10-16. [12] 杜龙, 刘晓峰, 汪金卫, 等.我国典型铜冶炼厂防渗设计探讨[J]. 有色金属科学与工程,2021,12(1):108-115.DU L, LIU X F, WANG J W, et al. Discussions on anti-seepage design of typical copper smelters in China[J]. Nonferrous Metals Science and Engineering,2021,12(1):108-115. [13] ZHU S F, ZHU D Y, WANG X H. Removal of fluorine from red mud (bauxite residue) by electrokinetics[J]. Electrochimica Acta,2017,242:300-306. doi: 10.1016/j.electacta.2017.05.040 [14] 禚文婧, 丁爱中, 贾文娟, 等.鄂尔多斯某燃煤电厂污染物在细砂和砂质粉土层中的运移规律[J]. 环境工程,2019,37(8):177-184.ZHUO W J, DING A Z, JIA W J, et al. Research on migration of pollutants from coal-fired power plants in the Ordos area in fine sand and sandy silt soil[J]. Environmental Engineering,2019,37(8):177-184. [15] 梁蓉蓉, 张永波.基于Hydrus-1d及解析法的灰场氟化物迁移动态研究[J]. 水电能源科学,2017,35(5):49-53.LIANG R R, ZHANG Y B. Fluoride migration dynamic research based on Hydrus-1d and analytic solution in ash yard[J]. Water Resources and Power,2017,35(5):49-53. [16] BERGER T, MATHURIN F A, DRAKE H, et al. Fluoride abundance and controls in fresh groundwater in Quaternary deposits and bedrock fractures in an area with fluorine-rich granitoid rocks[J]. Science of the Total Environment,2016,569/570:948-960. doi: 10.1016/j.scitotenv.2016.06.002 [17] 田富强, 温洁, 胡宏昌, 等.滴灌条件下干旱区农田水盐运移及调控研究进展与展望[J]. 水利学报,2018,49(1):126-135.TIAN F Q, WEN J, HU H C, et al. Review on water and salt transport and regulation in drip irrigated fields in arid regions[J]. Journal of Hydraulic Engineering,2018,49(1):126-135. [18] 阎婷婷, 吴剑锋.渗透系数的空间变异性对污染物运移的影响研究[J]. 水科学进展,2006,17(1):29-36. doi: 10.3321/j.issn:1001-6791.2006.01.005YAN T T, WU J F. Impacts of the spatial variation of hydraulic conductivity on the transport fate of contaminant plume[J]. Advances in Water Science,2006,17(1):29-36. doi: 10.3321/j.issn:1001-6791.2006.01.005 [19] 韩伟, 叶渊, 李彦希, 等.高氟地区电解铝厂场地氟污染特征及其风险评估[J]. 环境工程技术学报,2021,11(4):727-733. doi: 10.12153/j.issn.1674-991X.20200243HAN W, YE Y, LI Y X, et al. Fluorine pollution characteristics and risk assessment of electrolytic aluminum plant site in high fluoride area[J]. Journal of Environmental Engineering Technology,2021,11(4):727-733. doi: 10.12153/j.issn.1674-991X.20200243 [20] 何顺辉, 尹国盛, 安建杰, 等.新型GCL复合垂直防渗技术及其在填埋场的应用[J]. 环境卫生工程,2020,28(3):66-70.HE S H, YIN G S, AN J J, et al. New GCL composite vertical anti-seepage technology and its application in landfill[J]. Environmental Sanitation Engineering,2020,28(3):66-70. ◇