Assessment of nitrate transport parameters using the advection-diffusion cell

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• 作者：Taiseer Aljazzar ; Mohammed Al-Qinna
• 关键词：Nitrate ; Soil ; Groundwater ; Advection ; diffusion cell ; Transport ; Sorption ; Retardation
• 刊名：Environmental Science and Pollution Research
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：23
• 期：22
• 页码：23145-23157
• 全文大小：1,525 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Environment
  Environment
  Atmospheric Protection, Air Quality Control and Air Pollution
  Waste Water Technology, Water Pollution Control, Water Management and Aquatic Pollution
  Industrial Pollution Prevention
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1614-7499
• 卷排序：23

文摘

This study aimed to better understand nitrate transport in the soil system in a part of the state of North Rhine-Westphalia, in Germany, and to aid in the development of groundwater protection plans. An advection-diffusion (AD) cell was used in a miscible displacement experiment setup to characterize nitrate transport in 12 different soil samples from the study area. The three nitrate sorption isotherms were tested to define the exact nitrate interaction with the soil matrix. Soils varied in their properties which in its turn explain the variations in nitrate transport rates. Soil texture and organic matter content showed to have the most important effect on nitrate recovery and retardation. The miscible displacement experiment indicated a decrease in retardation by increasing sand fraction, and an increase in retardation by increasing soil organic matter content. Soil samples with high sand fractions (up to 94 %) exhibited low nitrate sorption capacity of less than 10 %, while soils with high organic matter content showed higher sorption of about 30 %. Based on parameterization for nitrate transport equation, the pore water velocity for both sandy and loamy soils were significantly different (P < 0.001). Pore water velocity in sandy soil (about 4 × 10−3 m/s) was about 100 to 1000 larger than in loamy soils (8.7 × 10−5 m/s). On the other hand, the reduction in nitrate transport in soils associated with high organic matter was due to fine pore pathways clogged by fine organic colloids. It is expected that the existing micro-phobicity increased the nitrate recovery from 9 to 32 % resulting in maximum diffusion rates of about 3.5 × 10−5 m/s2 in sandy soils (sample number CS-04) and about 1.4 × 10−7 m/s2 in silt loam soils (sample number FS-02).