A semiempirical mathematical model of the secondary pollution of water bodies by soluble iron and manganese forms

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• 作者：V. S. Savenko
• 关键词：iron ; manganese ; continental water bodies ; secondary pollution ; mathematical models
• 刊名：Water Resources
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：43
• 期：6
• 页码：862-872
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Hydrogeology; Hydrology/Water Resources; Waste Water Technology / Water Pollution Control / Water Management / Aquatic Pollution;
• 出版者：Pleiades Publishing
• ISSN：1608-344X
• 卷排序：43

文摘

A semiempirical mathematical model of iron and manganese migration from bottom sediments into the water mass of water bodies has been proposed based on some basic regularities in the geochemistry of those elements. The entry of dissolved forms of iron and manganese under aeration conditions is assumed negligible. When dissolved-oxygen concentration is <0.5 mg/L, the elements start releasing from bottom sediments, their release rate reaching its maximum under anoxic conditions. The fluxes of dissolved iron and manganese (Me) from bottom sediments into the water mass (J_Me) are governed by the gradients of their concentrations in diffusion water sublayer adjacent to sediment surface and having an average thickness of h = 0.025 cm: \({J_{Me}} = - {D_{Me}}\frac{{{C_{Me\left( {ss} \right)}} - {C_{Me\left( w \right)}}}}{h}\) (D_Me ≈ 1 × 10–9 m2/s is molecular diffusion coefficient of component Me in solution; C_Me(ss) and C_Me(w) ≈ 0 are Me concentrations on sediment surface, i.e., on the bottom boundary of the diffusion water sublayer, and in the water mass, i.e., on the upper boundary of the diffusion water sublayer). The value of depends on water saturation with dissolved oxygen (\({\eta _{{O_2}}}\)) in accordance with the empiric relationship \({C_{Me\left( {ss} \right)}} = \frac{{C_{_{Me\left( {ss} \right)}}^{\max }}}{{1 + k{\eta _{{O_2}}}}}\) (k is a constant factor equal to 300 for iron and 100 for manganese; C_Me(ss)max is the maximal concentration of Me on the bottom boundary of the diffusion water sublayer with C_Fe(ss)max ≈ 200 μM (11 mg/L), and C_Mn(ss)max ≈ 100 μM (5.5 mg/L).