# Transport in the Environment

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## Abstract

In this section various solution techniques for the convection-diffusion equation are reviewed, which is generally defined as the mass transport equation with diffusive terms. These techniques will be applied to chemical transport solutions in sediments. There are also a number of applications to chemical transport in biofilms. There are many other applications of the convection-diffusion equation, but they require more background with regard to the physics of mixing processes, which will be addressed in later sections of the volume.

## Keywords

Diffusion Equation Control Volume Diffusive Flux Flux Rate Computational Solution## Glossary

- Adsorption
The process of dissolved chemicals sticking to a solid.

- Convection
The movement of a constituent with movement of the fluid.

- Desorption
The detachment of a chemical from a solid.

- Diffusion
The spreading of fluid constituents through the motion inherent to atoms and molecules.

- Diffusion coefficient
A coefficient that describes the tendency of molecules to spread a constituent mass.

- Dirac delta
An impulse of a given quantity (mass) that occurs over an infinitely short time or space.

- Kinematic viscosity
The fluid viscosity divided by the fluid density, resulting in units that are similar to a diffusion coefficient, or length squared per time.

- Laminar flow
Flow that has no turbulent eddies, where the fluid flows in laminas and diffusion creates the mixing of the fluid.

- Retardation factor
A divisor that indicates the slowing of chemical movement through a media due to adsorption.

- Reynolds number
The ratio of inertial to viscous forces, resulting in a meaningful velocity times a meaningful distance divided by kinematic viscosity.

## Bibliography

## Primary Literature

- 1.Gulliver JS (2007) An introduction to chemical transport in the environment. Cambridge University Press, CambridgeCrossRefGoogle Scholar
- 2.Karikhoff SW, Brown DS, Scott TA (1979) Sorption of hydrophobic pollutants on natural sediments. Water Res 13:241CrossRefGoogle Scholar
- 3.Brunley BH, Jirka GH (1987) Near-surface turbulence in a grid-stirred tank. J Fluid Mech 183:235–263CrossRefGoogle Scholar
- 4.Campbell JA, Hanratty TJ (1982) Mass transfer between a turbulent fluid and a solid boundary: linear theory. AICHE J 28:988CrossRefGoogle Scholar
- 5.Janzen J, Jirka H, Jirka G, Schulz H, Gulliver JS (2010) Estimation of mass transfer velocity based on measured turbulence parameters. Am Inst Chem Eng J 56(8):2005–2017Google Scholar
- 6.Kreyszig E (1982) Advanced engineering mathematics, 4th edn. Wiley, New YorkGoogle Scholar
- 7.Lehman WJ, Reehl WF, Rosenblatt DH (1990) Handbook of chemical property estimation. American Chemical Society, Washington, DCGoogle Scholar
- 8.McCready MA, Vassiliadou E, Hanratty T (1986) Computer simulation of turbulent mass transfer at a mobile interface. AICHEJ 32(7):1108CrossRefGoogle Scholar
- 9.Fick AE (1855) Ueber Diffusion, Annelen der Physik 170(1):59–86CrossRefGoogle Scholar

## Books and Reviews

- Crank J (1975) The mathematics of diffusion, 2nd edn. Oxford University Press, OxfordGoogle Scholar
- Cussler EL (1997) Diffusion: mass transfer in fluid systems, 2nd edn. Cambridge University Press, CambridgeGoogle Scholar