Experimental study on dispersion coefficient of dredger fill in reclamation region

Abstract

In order to satisfy the demand of land use, reclamation engineering has been undertaken in coastal cities for a long time. To study the contaminant transport in the reclamation districts, robust and accurate estimation of dispersion coefficient is essential. In this study, the continuous sodium chloride (NaCl) solution with constant concentration was introduced into the column filled with the dredger fill to get the breakthrough curves(BTCs). Inverse error function method(IEFM) and CXTFIT program were used for estimating dispersion coefficient. Results showed that the difference between the dispersion coefficients estimated by IEFM and CXTFIT program was slight. The main reason was that the BTC was not strictly linear. IEFM performed poorly in the nonlinear area, while the CXTFIT performed well over the entire BTCs. Moreover, the dispersion coefficient of dredger fill was small. The dispersion property of dredger fill would result in the slow migration of contaminants in the dredger fill.

Keywords

dredger fill / hydrodynamic dispersion coefficient / IEFM / CXTFIT

References

[1] Peng T, Wu W, Huang S, et al. Research on engineering geologic properties of blown filled muck[J]. Geotechnical Investigation & Surveying, 1999 1-5.

[2] Niu C, Wang Q, Tan C, et al. Microstructure fractal feature of dredger fill during seepage flow consolidation[J]. Journal of Southwest Jiaotong University, 2012, 47(1): 78-83.

[3] Guo H P, Jiao J J. Impact of coastal land reclamation on ground water level and the sea water interface[J]. Groundwater, 2007, 45(3): 362-367.

[4] Zhang Q, Volker R E, Lockington D A. Experimental investigation of contaminant transport in coastal groundwater[J]. Advances in Environmental Research, 2002, 6(3): 229-237.

[5] Massoudieh A, Mathew A, Ginn T R. Column and batch reactive transport experiment parameter estimation using a genetic algorithm[J]. Computers & Geosciences, 2008, 34(1): 24-34.

[6] Cirpka O A, Olsson A, Ju Q, et al. Determination of transverse dispersion coefficients from reactive plume lengths [J]. Groundwater, 2006, 44(2): 212-221.

[7] Weiss M, Roberts M S. Tissue distribution kinetics as determinant of transit time dispersion of drugs in organs: Application of a stochastic model to the rat hindlimb[J]. Journal of Pharmacokinetics and Biopharmaceutics, 1996, 24(2): 173-196.

[8] Crowe A M, McClean C J, Cresser M S. An application of genetic algorithms to the robust estimation of soil organic and mineral fraction densities[J]. Environmental Modelling & Software, 2006, 21(10): 1503-1507.

[9] Toride N, Leij F J, Van Genuchten M T. The CXTFIT Code for Estimating Transport Parameters from Laboratory or Field Tracer Experiments [R]. 1995, 2nd ed., USA: Salinity Laboratory, Agriculture Research Service.

[10] Wang Q, Zhan H, Tang Z. A new parameter estimation method for solute transport in a column[J]. Groundwater, 2013, 51(5): 714-722.

[11] Ministry of Water Resources of the People’s Republic of China. GB/J 145-90 Soil Classification Standard [S]. 1991, Beijing, China: Chinese Standard Press.

[12] Li X, Du J, Cui J, et al. Application of calculating the diffusion coefficient of underground water: Bearing soil media through soil column tests[J]. Ground Water, 2012, 34(4): 20-22.

[13] Qian H, Ma Zhiyuan. Hydrogeochemical[M]. 2005, Beijing, China: Geological Publishing House.

[14] Fetter C W. Contaminant Hydrogeology [M]. 1999, 2nd ed.,

[15] Qi Z, Feng S, Helmers M J. Modeling cadmium transport in neutral and alkaline soil columns at various depths[J]. Pedosphere, 2012, 22(3): 273-282.