1. General form of the ADE:
sink/source term
Chemical sink/source term

2. Simple form of the ADE
Uniform 1D flow; longitudinal dispersion;
sink/source term

3. General form of the ADE:
sink/source term
Chemical sink/source term

4. We will consider two types of chemical reactions
Sorption (adsorption & absorption)
1st order irreversible reactions (radioactive decay,
hydrolysis, some forms of biodegradation)

5. LEA
sorption
1st order
(Zheng & Bennett)

6. Sorption (or retardation)
= v/vc
R > 1
Zheng & Bennett, Fig. 4.3

7. = v/vc
Zheng & Bennett, Fig. 4.3

8. LEA (Local Equilibrium Assumption)
Linear Isotherm
LEA (Local Equilibrium Assumption)
Zheng & Bennett, Fig. 4.2

9. Linear Isotherm
from MT3DMS manual

10. Simple form of the ADE
Retardation Factor
Uniform 1D flow; longitudinal dispersion;
sink/source term; retardation

11. Simple form of the ADE
= vc
R = v/vc

12. Freundlich Isotherms Unlimited sorption sites Linear Isotherm
Zheng & Bennett, Fig. 4.2

13. Freundlich Isotherm

14. Langmuir Isotherm
= maximum sorption capacity
Limited sorption sites

15. Langmuir Isotherm

16. fraction of organic carbon
Spitz and Moreno (1996)

17. Spitz and Moreno ( 1996)

18. General form of the ADE:
Chemical sink/source term

19. linear
Zheng & Bennett

20. We will consider two types of chemical reactions
Sorption (adsorption & absorption)
1st order irreversible reactions (radioactive decay,
hydrolysis, some forms of biodegradation) 

21. Simple form of the ADE
1st order rate constant
= ln 2 / half life = 0.693/ t½
Uniform 1D flow; longitudinal dispersion;
sink/source term; retardation; 1st order
irreversible reaction ( is the same for the
dissolved phase and the sorbed phase)

22. Zheng & Bennett