Applied Research Center Florida International University

1. Applied Research CenterFlorida International University Remediation and Treatment Technology Development and Support “Modeling Mercury Distribution in the Watersheds of the Oak Ridge Reservation” MIKE SHE and MIKE 11

2. Water & Environmental Resources Group Rajiv Srivastava, PhD – Associate DirectorGeorgio Tachiev, PhD – Project ManagerAngelique Lawrence, MS, GISP – Research AnalystPrabhakar Pant, MS, PWS – Research ScientistWeihua Zhang, PhD – Research ScientistYelena Katsenovich, PhD – Research Scientist

3. Background • FIU-ARC is providing technical assistance and performing research on mercury remediation at the Oak Ridge site through: • TASK I: Modeling of mercury speciation and distribution under buildings at Oak Ridge in the soil and groundwater. • Provide new insight to the potential risks of mercury contamination during D &D operations and thus develop strategies to minimize it. • TASK II: Identification and characterization of point and non-point sources of mercury in the LEFPC watershed to derive a conceptual model for the site with regard to mercury mass balance. • Re-establishing framework for Hg TMDL criteria currently established by EPA.

4. MIKE SHE & MIKE 11 • MIKE SHE - Numerical Integrated Hydrology Modeling • Covers the entire land phase of the hydrological cycle • Not just a 3-D numerical groundwater model - Includes numerical models for • overland flow • unsaturated flow • solute transport • agricultural practice • evapotranspiration • By default coupled to MIKE 11 • Ideal for distributed rainfall-runoff modeling • MIKE 11 - River and Channel Hydraulics • Versatile one-dimensional hydrodynamic software package • Includes process modules for • advection-dispersion • water quality and ecology • sediment transport • rainfall-runoff • flood forecasting

5. MIKE SHEIntegrated Surface Water and Ground Water Model • Dynamic, user-friendly modeling tool • Can simulate entire land phase of hydrologic cycle • Is applicable on spatial scales ranging from single soil profiles (for infiltration studies) to regional watershed studies • Integrated modeling environment • Links regional and local scale models • Can be linked to ESRI's ArcView for advanced GIS applications • Includes advanced tools for • Manipulating time varying data • Model calibration • Water and mass balance analysis • Proven track record in hundreds of consultancy and research applications worldwide

6. 1-dimensional unsaturated flow model Exchange across boundaries 3-dimensional saturated flow groundwater model (rectangular grid) MIKE SHEHydrologic Processes simulated by MIKE SHE

7. MIKE 11Dynamic modeling of river, channel and reservoir hydraulics • Industry standard for simulating • Flow and water level • Water quality and sediment transport in rivers, flood plains, irrigation canals, reservoirs and other inland water bodies • Transport and spreading of conservative pollutants and constituents with linear decay (including heat). • Dynamic integration with other DHI software allows integration of river & floodplain models with models for watershed processes, detailed floodplain representation, sewer systems & coastal processes • Links to external groundwater models and is OpenMI compliant • Significant components for FIU-ARC work: • GIS Extension - Powerful extension for ArcMAP providing features for • Catchment/river delineation • Cross-section and DEM data • Pollution load estimates • Flood visualization/animation as 2D maps • Results presentation/analysis using Temporal Analyst • Stream Flow Characteristics and Solute Transport modules. Includes • Unit hydrograph method • A lumped conceptual continuous hydrological model • A monthly soil moisture accounting model Reference: Graham, D.N. and M. B. Butts (2005) “Flexible, integrated watershed modelling with MIKE SHE.” Watershed Models, Eds. V.P. Singh & D.K. Frevert Pages 245-272, CRC Press. ISBN: 0849336090.

8. MIKE 11Modeling of non-point pollution

9. Thank youQuestions?

10. Thank youQuestions??

11. An integrated model showing the groundwater table as function of time for a period of 10 years. The following specifications are included: -evapotranspiration -precipitation -saturated groundwater flow -unsaturated groundwater flow -river flow -exchange between: River and groundwater Saturated and usaturated zone

12. COMSOL MultiphysicsEarth Science Module • Simulates physics involved in fluid flow, heat transfer, and solute transport • Includes modeling interfaces for • Heat Transfer • Richards equation • Darcy’s Law • Solute transport in saturated and variably saturated media • Also offers • Unlimited multiphysics couplings - Ties seamlessly into COMSOL Multiphysics and other auxiliary modules to truly model coupled phenomena in the earth. These include poroelasticity, electromagnetic fields, acoustic and structural behavior, and chemical reactions. • Equation-based modeling - All material properties, source terms, and boundary settings can be represented by any arbitrary function of pressure, temperature, concentrations, stress, or any other variable or parameter: In particular, full two-phase flow in porous media can be simulated in this way. • Accessing data - The module features unsurpassed ease with which users can work with field-gathered data and then couple these to descriptions of material properties.

13. COMSOL Multiphysics2-Phase Flow in Porous Media • Flow of air and water within the domain. Uses Richard’s equation to describe • Flow in Saturated zone • Flow in Unsaturated zone • Gas flow • Transport of mercury in variably saturated media and in the gas phase. Takes into account exchange with infinite layer above the domain by diffusion and convection (wind effects) • Incorporates physicochemical behavior of Hg in soil, water, air phases • Adsorption • Bio- and chemical transformation

14. Visual MINTEQ • This model is used for calculating the equilibrium mass distribution among dissolved species, adsorbed species, and multiple solid phases under a variety of conditions including a gas phase with constant partial pressures. • Used to calculate equilibrium composition of aqueous solutions in ORR groundwater contaminated with 0.2µg/L of mercury. • Field and laboratory analytical data used in the model were acquired from the OREIS database.

15. Visual MINTEQ • Mercury binding to humic substances is an important process in ground and surface waters. • Visual MINTEQ permits use of three (3) different models for computing the complexation of mercury by dissolved organic matter (DOM). • Gaussian • Does not seem to compute mercury bound to DOM and results with DOM input were not differing from the inorganic mercury compounds distribution without DOM. • NICA-Donnan Model & Stockholm Humic Model (SHM) • Results from these suggest that mercury is in the dissolved phase and almost 99.89% bound to DOM with concentrations starting as low as 0.5ppm. • NICA-Donnan model is available only for aqueous mercury speciation and provides comparison between site-specific fulvic acid (FA), which are type 1 (carboxylic - FA1) and type 2 (phenolic and other - FA2). • Preliminary modeling results indicate that the percentage of mercury bound to FA1 and FA2 depends on groundwater ORP conditions.

16. GEMS-PSI  Gibbs Energy Minimization Selektor(PSI version)for Geochemical Equilibrium Modeling • Broad-purpose geochemical modeling codeusing an advanced convex programming method of Gibbs Energy Minimization (GEM) implemented in an efficient Interior Points Method (IPM) numerical module. • Can compute equilibrium phase assemblage and speciation in a complex chemical system from its total bulk elemental composition at given temperature and pressure (optionally, with some metastability or kinetic constraints). • Chemical interactions involving (dispersed) solids, solid solutions, gas mixture, aqueous electrolyte  (non-)electrostatic surface complexation, and ion exchange can be considered simultaneously in the chemical elemental stoichiometry (+ electrical charge) of the system, i.e. without any additional mass balance constraints for ligands or surface sites.

17. N Progress To Date • Delineation of Lower East Fork Poplar Creek (LEFPC) and White Oak Creek watersheds/sub-catchments using ArcGIS and the ArcHydro model. • Preliminary simulation of overland and saturated flow in the White Oak Creek Watershed using MIKE SHE

18. N Progress To Date • Creation of 3-D mesh for topography of Central Bethel Valley area to examine mercury contamination within ORNL area at a smaller scale as opposed to a watershed perspective. • Creation of 3-D visualizations for Central Bethel Valley mercury contamination. Melton Valley Access Rd Bldgs. 4501/4505 Bethel Valley Rd. White Oak Creek 2005 GW Hg. Conc. (µg/L) First Creek 7500 Bridge

19. Path Forward • A multidisciplinary approach to complex environmental problems • Physico-Chemistry, experimental work • Transport on microscale • GIS and regional modeling • Regulatory compliance

20. Project Overview • Saltcake dissolution studies • Hydraulic properties of saltcake simulants • Oxidative Leaching • Gas Release and Retention • Modeling of flow through saltcake

21. Saltcake Dissolution

22. Saltcake Dissolution Experimental Scale

23. Saltcake Dissolution Preferential Flow and DIssolution

24. Saltcake Dissolution Beginning and end of dissolution

25. Saltcake Dissolution Retrieval Efficiency

26. Saltcake Dissolution Sodium Retrieval Patterns

27. Saltcake Dissolution Aluminum Retrieval Patterns

28. Saltcake Dissolution Nitrite Retrieval Patterns

29. Saltcake Dissolution Phosphate Retrieval Patterns

30. Hydraulic Parameters Inverse modeling of effluent rates using van Genuchten’s theory for variably saturated flow

31. Hydraulic Parameters Hydraulic properties of aging simulant

32. Hydraulic Parameters I II III Variation of hydraulic conductivity

33. Hydraulic Parameters Tracer Studies

34. Numerical Modeling Continuous retrieval and dispersion factors

35. Numerical Modeling Incremental Drainage and Resaturation

36. Oxidative Leaching Chromium (III) speciation

37. Oxidative Leaching Chromium (III) speciation

38. Oxidative Leaching Pu Predominance Diagram

39. Oxidative Leaching Pu Predominance Diagram

40. Gas Release and Retention Experimental Setup

41. Gas Release and Retention Argon Injection and Release

42. Gas Release and Retention Argon Injection and Release – Time constants

43. THE END End