{[ promptMessage ]}

Bookmark it

{[ promptMessage ]}

Lecture.Packet.6.advection.dispersion

Lecture.Packet.6.advection.dispersion - CHAPTER 4 SITE...

Info icon This preview shows pages 1–6. Sign up to view the full content.

View Full Document Right Arrow Icon
CEE 440 © 2011 Charles J. Werth, University of Illinois at Urbana-Champaign. All rights reserved. 1 CHAPTER 4. SITE PROPERTIES AFFECTING REMEDIATION My teaching goals for this chapter are for you to: 1) learn how site specific properties affect contaminant transport in soil and groundwater 2) Derive the advection-dispersion equation 3) Calculate travel times for contaminants in groundwater based on relevant hydraulic properties 4) Evaluate how dispersion processes dilute contaminants in groundwater
Image of page 1

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CEE 440 © 2011 Charles J. Werth, University of Illinois at Urbana-Champaign. All rights reserved. 2 TRANSPORT PROPERTIES: ADVECTION, DISPERSION, AND SORPTION Transport properties refer to all of the factors that influence the movement of contaminants in the subsurface. The physics of transport are a function of what phase the contaminants are in. In CEE440 we will focus primarily on aqueous and vapor phase transport. Transport of pure phase chemicals is a complex problem that is best left to a course which focuses on multiphase flow. In CEE440 we will derive partial differential equations that describe the processes which affect transport. Analytical solutions to these equations will be provided for you. You will work with these solutions to evaluate how subsurface parameter affects contaminant transport.
Image of page 2
CEE 440 © 2011 Charles J. Werth, University of Illinois at Urbana-Champaign. All rights reserved. 3 Geologic/Hydrogeologic Heterogeneity An extremely important factor that we will only consider qualitatively is heterogeneity. Heterogeneity exists at all scales (i.e. at both the pore and the Darcy scale) and results in highly variable contaminant distributions in the subsurface. Heterogeneity is one of the biggest obstacles facing Environmental Remediation and the focus of much current research (including mine). TILL BEDROCK SAND AND GRAVEL FRACTURED ROCK LOW PERMEABILITY CLAY & SILT Figure 4.1. Illustration of subsurface heterogeneity
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
CEE 440 © 2011 Charles J. Werth, University of Illinois at Urbana-Champaign. All rights reserved. 4 A couple of definitions: Water table - surface along which all pores are filled with water at atmospheric pressure Aquifer- porous medium capable of storing water and transport substantial quantities of water under natural conditions; can be a uniform porous media such as sand or a highly variable one such as fractured rock; can be either confined or unconfined. Classification of soil components based on particle size: Clay Silt Sand Gravel < 2 μ m 2 μ m – 63 μ m 63 μ m – 2 mm > 2 mm
Image of page 4
CEE 440 © 2011 Charles J. Werth, University of Illinois at Urbana-Champaign. All rights reserved. 5 4.1. Groundwater Flow Rate - ADVECTION Flow through an aquifer is laminar (exceptions in fractured rock) and described by Darcy’s law: Q Q z 1 z 2 h p,1 h p,2 h 1 = z 1 + h p,1 h 2 = z 2 + h p,2 Δ h = h 2 - h 1 h = hydraulic head h p = pressure head z = elevation head v = Q/A = - K H dh / dl (4.1) v =Darcy flux or specific discharge [m/s] Q = volumetric discharge [m 3 /s] A = cross-sectional area [m 2 ] dh / dl = hydraulic gradient varies from 10 -5 to 10 -1 , typical value is 10 -3 K H = hydraulic conductivity [m/s]
Image of page 5

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Image of page 6
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern