HESSD

Hydrology and Earth System Sciences Discussions

HESSD

Hydrol. Earth Syst. Sci. Discuss.

1812-2116

Göttingen, Germany

10.5194/hess-2018-462

Analytical model for coupled multispecies advective dispersive transport subject to rate-limited sorption

Chen

Jui-Sheng

¹ Ho

Yo-Chieh

¹ Liang

Ching-Ping

² Wang

Sheng-Wei

https://orcid.org/0000-0001-5729-1978

³ Liu

Chen-Wuing

⁴

Graduate Institute of Applied Geology, National Central University, Taoyuan City 320, Taiwan

Department of Nursing, Fooyin University, Kaohsiung City 831, Taiwan

Sinotech Environmental Technology, Ltd, Taipei 105, Taiwan

Department of Bioenvironmental Systems Engineering, National Taiwan University, 13 Taipei 10617, Taiwan

MOST 106-2622-M-008-001-CC2

02 10 2018

2018 1 45

2018

This work is licensed under the Creative Commons Attribution 4.0 International License. To view a copy of this licence, visit https://creativecommons.org/licenses/by/4.0/

This article is available from https://hess.copernicus.org/preprints/hess-2018-462/

The full text article is available as a PDF file from https://hess.copernicus.org/preprints/hess-2018-462/hess-2018-462.pdf

Mathematical models that analytically solve a set of simultaneous multispecies advection-dispersion transport equations coupled with a series of chemical reactions are cost-effective tools for predicting the plume migration of dissolved chlorinated solvents and nitrogen chains. However, few analytical solutions for coupled reactive multispecies transport equations have appeared in the literature. For convenience of mathematical derivation, most analytical models currently used to simulate multispecies transport assume instantaneous equilibrium between the dissolved and sorbed phases of the contaminant. However, research has demonstrated that rate-limited sorption process can have a profound effect upon solute transport in the subsurface environment. Making the instantaneous equilibrium sorption assumption precludes consideration of potential effects of the rate-limited sorption. This study presents a novel analytical model for simulating the migrations of plumes of decaying or degradable contaminants subject to rate-limited sorption. The derived analytical model is then applied to investigate the effects of the rate-limited sorption on the plume migration of degradable contaminants. Results show that the kinetic sorption rate constant has significant impacts on the plume migration of degradable contaminants. Increasing the kinetic sorption rate constant results in a reduction of predicted concentration for all species in the degradable contaminants while the equilibrium-controlled sorption model lead to significant underestimation of the concentrations of degradable contaminants under conditions with low sorption Damköler number, Dai = βiLν. The equilibrium-controlled sorption model agrees well with the rate-limited sorption model when the Damköler number is greater than 2 to 3 order of magnitude. The invalidity of the equilibrium-controlled sorption model of low Damköler number case implies that the health risk could be underestimated if such a model is used for assessing the concentrations of the degradable contaminants in the health risk model.