1. Groundwater Environment Significance of Groundwater Pollution Control Hydrologic Cycle Definitions and Physical Principles Groundwater Geology

2. Estimated World Water Quantities (World Water Balance and Water Resources of the Earth, Copyright, UNESCO, 1978) ItemVolume (km 3 ) Percent of total waterPercent of fresh water Oceans Groundwater - Fresh - Saline Soil moisture Polar ice Other ice and snow Lakes - Fresh - Saline Marshes Rivers Biological water Atmospheric water Total water Fresh water 1,338,000,000 10,530,000 12,870,000 16,500 24,023,500 340,600 91,000 85,400 11,470 2,120 1,120 12,900 1,385,984,610 35,029,210 96.5 0.76 0.93 0.0012 1.7 0.025 0.007 0.006 0.0008 0.0002 0.0001 0.001 100 2.5 30.1 0.05 68.6 1.0 0.26 0.03 0.006 0.003 0.04 100

3. Residence Time (T R ) - average duration for a water molecule to pass through a subsystem of the hydrologic cycle. T R = Volume in Storage / Flow Rate

4. Residence Time (T R ) - average duration for a water molecule to pass through a subsystem of the hydrologic cycle. T R = Volume in Storage / Flow Rate ItemResidence Time Oceans Ice caps & glaciers Lakes & reservoirs Rivers Soil moisture Atmospheric water Groundwater 4000 years 10 - 1000 years 10 years ~ 2 weeks 2 weeks - 1 year ~10 days 2 weeks - 10,000 years

5. Soil Water Zone Intermediate Vadose Zone Capillary Zone Groundwater Impermeable Layer Soil Moisture Profile Unsaturated Zone Saturated Zone FLOW Water Table (phreatic surface) Vadose zone Phreatic zone Water in chemical combination with rock

6. Saturation (S) = V w / V v Range: 0 -> 1. Porosity (n) = V V / V T. Moisture Content (ø) = V w / V T Range: 0 -> n. Void Ratio (e) = V V / V S Field Capacity = amount of water held in soil after wetting and drainage. e = n / (1-n) or n = e / (1+e). Here: V W - volume of water in an overall soil matrix V V - volume of void in an overall soil matrix V S - volume of soil in an overall soil matrix V T - total volume of overall soil matrix ( = V W + V V +V S ) Primary porosity (interstitial porosity) vs. Secondary porosity (fracture, solution porosity) "Apparent" porosity vs. "Effective" porosity (interconnected pore space) Definitions

7. Secondary porosity

8. Definitions: Aquifer Types Aquifer: geologic formation which a) contains water b) permits significant transmission Classification 1) Confined - bounded above and below by confining formations Artesian - wells flow freely 2) Unconfined (phreatic) - water table serves as upper boundary 3) Aquitard: aquifer loses or gains water through bounding formations cf) aquiclude - contains water but will not transmit aquifuge - impervious (neither contain water nor transmit water) Def: Piezometric Head - water level in well which penetrates aquifer. Piezometric Surface - imaginary surface defined by such wells.

10. Definitions II Permeability: Capacity of porous medium to transmit water Average water flow velocity is used as a quantitative measure of permeability (Length per time). Homogeneity: A formation is said to be homogeneous if the properties are the same at all points. Otherwise, the formation is heterogeneous. (An)Isotropy: A formation is said to be isotropic if its properties are independent of direction at a point. Otherwise, the formation is anisotropic.

11. GW Geological Elements controlling the nature and distribution of aquifers and aquitards in a geologic system Lithology: physical make-up, including the mineral composition, grain size, and grain packing, of the sediments or rocks that make up the geological systems Stratigraphy: the geometrical and age relations between the various lenses, beds, and formations in geologic systems of sedimentary origin. Structural features: such as cleavages, fractures, folds, and faults are the geometrical properties of the geologic systems produced by deformation after deposition. Unconformity: surface that represents an interval of time during which deposition was negligible or nonexistent, or more commonly during which the surface of the existing rocks was weathered, eroded, or fractured.

12. Genesis of Aquifer Unconformity: surface that represents an interval of time during which deposition was negligible or nonexistent, or more commonly during which the surface of the existing rocks was weathered, eroded, or fractured. Weathering In-situ physical disintegration and chemical decomposition Erosion Wind, running water, glacier ice Deposition Nonindurate deposits (90% of all development aquifers) Sedimentary rocks Igneous and metamorphic rocks Permafrost

13. Major types of aquifer systems 1. Alluvial aquifers Alluvium - sediments of recent geologic age deposited by flow water (a) deposits in braided rivers, (b) deposits in meandering rivers and floodplain environments, (c) deltaic deposits etc. 2. Glacial aquifers - tills (low permeability, poorly sorted) 3. Aeolian aquifers - loess (relatively uniform distribution of porosity) 4. Sedimentary aquifers - more advanced consolidation & cementation (of greater age than unconsolidated deposits). Sandstones: porosity reduced by chemical precipitation Shales: secondary porosity along bedding planes, fractures, joints Carbonate rocks: deposition from marine organisms (limestones, chalks, dolomites); secondary porosity along channels, sinkholes. 5. Igneous and metamorphic rocks - extremely anisotropic, varying hydraulic properties, low porosity Intrusive igneous rocks: post-emplacement changes (secondary porosity) Metamorphic rocks: principal rocks of the continental core Extrusive Igneous rocks: contains reasonably large volumes of water.

14. Review: Environ. Processes & Dynamics Transformation Homogeneous Heterogeneous Transport Microscopic transport Macroscopic transport Interphase mass transfer

15. Transformation Definition: Reactions resulting in the change of one chemical form, species, or state to another (chemically changed). Virtually all environmental transformations are chemically mediated. Homogeneous (mono-phase) Heterogeneous (multi-phases) => More environ. relevant * Nevertheless, within a mono-phase, transformation is not necessarily heterogeneous In nature

16. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Transport Processes (I) 4.A Basic Concepts and Mechanisms – Contaminant Flux – Advection – Diffusion – Dispersion 4.D Transport in Porous Media – Fluid Flow through Porous Media – Contaminant Transport in Porous Media

17. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Mechanisms of mass transport and transfer Pollutant Mass in Bulk Fluid Control Element Porous Solid Intra-phase Diffusion Boundary Layer Inter-phase Mass Transfer Advection (by Water Flow) Bulk-phase diffusion (by Conc. Gradient) Dispersion (by Momentum Gradient) X-direction Y-direction by Diffusion

18. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Definition: Flux of material i Flux of material i (Ni) = The number of moles of material i transported per unit cross-sectional area per unit time = # mole of material i dA * dt

19. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Reynolds transport theorem: Mass continuity Magnitude of the molar flux normal to a differential element of surface area, dA = |N i | cos θ = N i. n v Flux is a Vector: N i = N ix i x + N iy i y + N iz i z ~ ~

20. Characterization of Flow Steady Flow Unsteady Flow Uniform Flow Nonuniform Flow Steady State For Turbulent Flow

21. CEE3330-01 May 8, 2007 Joonhong Park Copy Right 1-D Advective Flux of Contaminant C IN (contaminant concentration) V (water velocity) Flux N @ X= C*∆L * A / A (∆L /V) = C*V ΔLΔL A C IN V XΔLΔL A t t + ΔL/V Assumption: Steady State Uniform Water Flow Field

22. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Molecular Diffusion The random motion of fluid molecules causes a net movement of species from regions of high concentration to regions of low concentration. The rate of movement depends on the spatial gradient of concentration of a solute. Our discussion is restricted to conditions in which the diffusing species is present at a low mole fraction (the infinite dilution condition).

23. CEE3330-01 May 8, 2007 Joonhong Park Copy Right 1-D Diffusive Flux of Contaminant t =0 t=t 1 t=t 2 t=t 3

24. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Fick’s 1 st Laws D i : Diffusion coefficient or diffusivity a property of the diffusing species For molecules in air, typically D values is 0.1 cm 2 /s For molecules in water, typically D values is 10 -5 cm 2 /s

25. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Example Passive Dosimetry Ambient Concentration Co=? (Assumption: Co =constant) Adsorbent Co 0 Diffusion Distance L M t : accumulated mass at t.

26. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Fick’s 1 st Laws D i : Diffusion coefficient or diffusivity a property of the diffusing species For molecules in air, typically D values is 0.1 cm 2 /s For molecules in water, typically D values is 10 -5 cm 2 /s

27. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Albert Einstein’s Solution X: traveling distance t: traveling time D: Diffusion coefficient

28. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Example Passive Dosimetry Ambient Concentration Co=? Adsorbent Co 0 Diffusion Distance L

29. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Dispersion The spreading of contaminants by nonuniform flow is called dispersion. This is not a fundamentally distinct transport process. Instead, dispersion is caused by nonuniform advection and influenced by diffusion. A phenomenon caused by the gradient of momentum, which is expressed by a tensor.

30. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Types of Dispersion Processes Slow dispersion Rapid dispersion Slow dispersion Side view Top view

31. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Types of Dispersion Processes Taylor (Shear Flow) Dispersion: occurs in laminar flow (pipes and narrow channels); transverse direction of solute movement driven by solute concentration gradient Turbulent (eddy) dispersion: velocity fluctuations created by fluid turbulence acting across large advection-dominated fields; large channels, rivers, streams, and lakes. Hydrodynamic and mechanical dispersion: flow in porous media (activated carbon filters; groundwater)

32. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Shear Flow Dispersion (in a laminar flow) Injected pulse @ t=0 Dispersed pulse @ t=t Factors to cause the dispersion -Average effect -Concentration gradient due to velocity gradient (momentum gradient) Fluid velocity profile Concentration gradient

33. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Turbulent Dispersion y x U y C Gaussian Normal Distribution

34. Energy Balance and Bernoulli Eq. A1A1 A2A2

35. Momentum Balance Momentum Flux x y z Newtonian fluid

36. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Dispersion Equation Dispersivity (Tensor) Free-Liquid Molecular Diffusion Coefficient (Scalar) Identity Matrix

37. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Dispersion Distance X: traveling distance t: traveling time Ddd: Dispersion coefficient

38. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Water Flow in Porous Media - History and equation. - Determination of K and k.

39. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Darcy’s Experiment (1856) Flow of water in homogeneous sand filter under steady conditions Datum h1h1 h2h2 Sand Porous Medium L A: cross area Q = - K * A * (h 2 -h 1 )/L K= hydraulic conductivity

40. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Darcy’s Experiment (1856) Flow of water in homogeneous sand filter under steady conditions Datum h1h1 h2h2 Sand Porous Medium L A: cross area Q = - K * A * (h 2 -h 1 )/L K= hydraulic conductivity

41. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Darcy’s Law Q = - K * A * (Φ 2 - Φ 1 )/L Φ piezometric head In a 1-D differential form, Darcy’s law may be: q = Q/A = - K * [dΦ/dL] Hydraulic Conductivity, K (L/T) K Ξ k * ρ * g / μ Here, k = intrinsic permeability (L 2 ) ρ: fluid density (M L -3 ); g: gravity (LT -2 ) μ: fluid viscosity (M L -1 T -1 )

42. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Typical values of K and k PermeableSemi-permeableImpermeable Permeability Aquifer Soils Rocks -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Good PoorNone Clean gravel Clean sand or Sand and gravel Very fine sand, silt, Loess, loam, solonetz Unweathered clay Stratified clayPeats Oil rocks SandstoneGood Limestone dolomite Breccia, granite -log K (cm/s) -log k (cm 2 )

43. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Hydrodynamic Dispersion Mechanical Dispersion (Tensor) In one-D system, Molecular Diffusion (Scalar) Identity Matrix α, dispersivity V, pore velocity (=q/n)

44. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Transport and dispersion of a fixed quantity of a nonreactive groundwater contaminant X y t1 t2 t3

45. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Mass-transfer coefficient

46. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Film Theory Ci C Well-mixed fluid Stagnant Fluid film Boundary Flux Lf

47. CEE3330-01 May 8, 2007 Joonhong Park Copy Right Penetration Theory Ci C Well-mixed fluid Stagnant Fluid film Boundary Flux Lf t3 t2 t1 instantaneous

48. Water-Air Interface (Double-Layer Theory) Pi P Partial Pressure Turbulently mixed zone Stagnant film layer Boundary Flux La Stagnant film layer Turbulently mixed zone C Ci Lw Air Water

49. 2016-06-04CEE3330-01 Joonhong Park Copy Right Reactor Concepts Review of Ideal Reactor Models - CMBR - CM(C)FR - PFR Advanced Ideal Reactor Problems

50. 2016-06-04CEE3330-01 Joonhong Park Copy Right Ideal Reactors Completely Mixed Batch Reactor (CMBR) Completely Mixed Continuous Flow Reactor (CMCFR) Q-In Q-out Plug-Flow Reactor (PFR) Q-InQ-out

51. 2016-06-04CEE3330-01 Joonhong Park Copy Right General Material Balance Model Net rate of transformation of material i within the control volume Net rate of change (either accumulation or depletion) of material i within the control volume ± = Molar rate of input of material i across the control volume boundaries Molar rate of output of material i across the control volume boundaries -

52. CEE3330-01 Joonhong Park Copy Right Completely Mixed Batch Reactor (CMBR) CMBR Material Balance Net accumulation rate in reactor, d(CV) reactor /dt = net transformation rate (dC/dt) reaction V When V = constant, [dC/dt] reactor = [dC/dt] reaction = r V: reaction volume C: contaminant concentration

53. 2016-06-04CEE3330-01 Joonhong Park Copy Right Completely Mixed Continuous Flow Reactor (CMCFR) or “CSTR” Q Q Completely Stirred Tank Reactor (CSTR) V = Reactor volume C = concentration in reactor d(CV)/dt = Q * C in – Q * C + r * V C in C dC/dt = Q/V * (C in – C) + r Here V/Q = Θ = hydraulic resistant time Example: When the reaction is a first order decay, what will be the efficiency in the reactor under steady state conditions? dC/dt = 0= 1/Θ * (C in – C) + r = 1/Θ * (C in – C) – k * C C/C in = 1/(1 + k * Θ)

54. 2016-06-04CEE3330-01 Joonhong Park Copy Right V Q Q C in C out Q C in Q C out V/2 QC1QC1 Assumptions: stead state conditions Ideal CSTR the first order decay reaction with a rate constant, k. Givens: V=10,000 L, Q=100L/h, k=1.0/h Mission: Compare the treatment efficiencies (1- Cin/Cout), and discuss the effect of sectionization of the reaction on the treatment efficiencies. Answers: (1- 1/101) vs (1-1/2601) = 99.00% vs. 99.96% Example:

55. 2016-06-04CEE3330-01 Joonhong Park Copy Right Completely Mixed Continuous Flow Reactor (CMCFR) Q Steady State Efficiency of CSTRs in Series V = Overall Reactor Volume C in C 1 /C in = 1/(1 + k * Θ/2) Q C1C1 C2C2 V/2 C 2 /C 1 = 1/(1 + k * Θ/2) C 2 /C in = 1/(1 + k * Θ/2) 2 C out /C in = 1/(1 + k * Θ/n) n When n = large, C out /C in = Exp (-k Θ)

56. 2016-06-04CEE3330-01 Joonhong Park Copy Right Q Steady State Efficiency of CSTRs in Series V = Overall Reactor Volume C in C1C1 C n-1 V/n C out /C in = 1/(1 + k * Θ/n) n When n = large, C out /C in = Exp (-k Θ) Q CnCn V/n …..

57. 2016-06-04CEE3330-01 Joonhong Park Copy Right Material Balance in PFR C IN V (water velocity) X ΔXΔX CXCX C X+ΔX Missions: 1.Governing equation (point form) 2.Calculate concentration as a function of distance, X A

58. 2016-06-04CEE3330-01 Joonhong Park Copy Right Material Balance in PFR Assumptions V and C IN are constant. Reaction rate = - kC (first order rate) Steady State (dC/dt=0).

59. 2016-06-04CEE3330-01 Joonhong Park Copy Right Comparison of CMFR and PFR HW: Draw the C/C-in versus kΘ plot for 1 st order decay And discuss why the differences occur. (hint: see p. 233 and 229 in your course material)

60. 2016-06-04CEE3330-01 Joonhong Park Copy Right Point Form of Mass Continuity Relationship Δx ΔzΔz Δy N| X N| X+ΔX N| Z+ΔZ N| X N| y N| y+Δy - (δNx/δx+ δNy/δy+ δNz/δz) + r = δC/ δt Divide all the terms in Eq. 2-17 (text book) by ΔxΔyΔz, and then, Question: Dimension of unit of each term?

61. 2016-06-04CEE3330-01 Joonhong Park Copy Right Inter-phase Mass Transfer Phase 1 Boundary Layer Inter-phase Mass Transfer X-direction Y-direction Phase 2 CoCo C k: Inter-phase Mass Transfer Coefficient (L/T)

62. 2016-06-04CEE3330-01 Joonhong Park Copy Right Completely Mixed Batch Reactor (CMBR) CMBR Material Balance Net accumulation rate in reactor, d(CV) reactor /dt = net transformation rate (dC/dt) reaction V When V = constant, [dC/dt] reactor = [dC/dt] reaction = r V: reaction volume C: contaminant concentration When inter-phase mass transfer is involved, Net accumulation rate in reactor, d(CV) reactor /dt =N*A = k m (C-C o ) A Phase j (ex. activated carbon) C: concentration in phase i Co: concentration in phase j A: overall surface area where the interphase mass transfer occurs Phase I (ex. water)

63. 2016-06-04CEE3330-01 Joonhong Park Copy Right Inter-phase Mass Transfer in PFR V A volatile organic compound is steadily discharged into the river. It undergoes first-order chemical decay within the water and interphase mass transfer across the water-air surface. x∆x C IN C: VOC concentration in water phase C a : VOC concentration in air phase K a-w : air-water interphase mass transfer rate constant (1/T) A W HW: Get the steady-state analytical solution for when Ca=0 (hint: see p. 235 in your course material)

64. Advection-Dispersion-Reaction (ADR) Equation C IN V (water velocity) is varying! X ΔXΔX CXCX C X+ΔX A

65. 2016-06-04CEE3330-01 Joonhong Park Copy Right 1-D ADR Equation - (δNx/δx) + r = δC/ δt

66. 1-D Solute ADR Equation In a porous medium, q = nV (here n = porosity)

67. Dispersion Number

68. CEE3330-01 May 29, 2006 Joonhong Park Copy Right Example A bathing beach Instantaneous Increase & Continuous Input of E. coli C IN = 400 cells/100 mL Velocity of River, V = 10 km/day Waste Water Treatment The 1 st order die-off rate of E. coli in river, k=0.5 1/day (reaction rate = -kC) Question: Will the bathing standard be violated at the beach? L = 10 km C at L (beach) Dispersion Coeff, D d = 10 km 2 /day

69. CEE3330-01 May 29, 2006 Joonhong Park Copy Right 1.ADR Equation can be applied in this analysis. 2. Initial and Boundary Conditions? 3. Use the analytical solution. Assumptions 1.The first order decay rate: r = - k * C (valid for decay of bacterial cells when food is limited.) 2. Steady State Assumption: If the river flow and bacteria count at the discharge point are reasonably constant in time (i.e., V=constant, C IN =constant at t>0). Governing Equation and Solving the Problem C=400*0.619 = 248 cells/100mL > standard

70. CEE3330-01 May 29, 2006 Joonhong Park Copy Right Effect of Dispersion Number on C/C IN at Effluent

71. CEE3330-01 May 29, 2006 Joonhong Park Copy Right Stepped Input Analytical solution is available 1- and 2-D for homogeneous systems with uniform velocity C=0 at t=0 0 ≤ x ≤ ∞ C=Co at x=0 t > 0 x =>∞ t>0 Initial and Boundary Conditions

72. 3000 m Co V Break Through Curve at Effluent t=0

73. A+D: Advection, dispersion; A+10xD: Advection + 10X Dispersion A+D+R: Advection+Dispersion+1 st Order Decay

74. Homogenous Reactions Homogenous reactions are governed by relations which require that certain entropy, enthalpy, and energy balances be obeyed among the components or species participating in transformation processes that occur within a single phase. * Transformation via electron transfer (oxidation-reduction reaction) - Ionic reaction (give-and-take) - covalent reaction (sharing) - coordinate-covalent reaction (forming complexes) * Transformation via proton (H + ) transfer (in water)

76. Equilibrium distribution of a species among different phases are governed by thermodynamics (driving forces = chemical energy differences between different phases). Examples of heterogeneous reactions Gas & Water: Volatilization, Henry constant, K H P A = K H * C A, (P i = [n i / V]*R*T) here, P=partial pressure, C=molar conc. Water & Organic phase: Partitioning, Octanol-Water Partition Coeff., K O-W C A in organic = K O-W * C A in water Solid & Water: (Linear) Adsorption Coeff., Kd C A in solid = Kd * C A in water Heterogeneous Reactions

77. Transport processes as the result of specific “driving forces” - In essence, a driving force is a spatial energy gradient of a species - elevation head, pressure gradient, density gradient, concentration gradient, chemical energy gradient, electrical energy gradient Macroscopic transport processes occur at the scale of the system or reactor - In most cases, physical and mechanical driving force. Microscopic transport processes occur at the scale of subcomponents (e.g. suspended particles, phase interfaces etc.) - Concentration/chemical energy-driven transport at a microscopic scale (a nano-scale) Transport processes

78. Characterizing (i) input and output of a material, and (ii) the way of mixing of a material is getting more important Mechanism of chemical reaction is getting more important Mega-system (Lake) Micro-system Mega-system (the Earth)

79. Process Complexity Relative Reaction Complexity Relative System Complexity Megasystems Macrosystems Microsystems Component induced Scale induced