Use of an Alternative Paradigm to Support Optimization of In Situ - PowerPoint PPT Presentation

Use of an Alternative Paradigm to Support Optimization of In Situ Remedies at Metal and Radionuclide Contaminated Sites Radionuclide Contaminated Sites ‘The Virtual Test Bed’ Carol A. Eddy-Dilek (SRNL), Miles Denham (SRNL), and Haruko M. Wainwright (LBNL) Federal Remediation Technology Roundtable November 2, 2016

The EM Challenge The EM Challenge (1995)  16 107 107 maj jor si ites (1995) 16 si ites (2016) (2016)

The EM Challenge The EM Challenge yxwvutsrponmlkihgfedcbaWVUSRPONMLIHGFEDCBA • Remediation of large complex groundwater plumes of metals and long-lived radionuclides (e.g., Tc, I) • Transition from active remediation systems (P&T) to passive methods (Monitored Natural Attenuation) • DOE sites (RL, SRS, Paducah, LANL, LM) DOE sites (RL SRS Paducah LANL LM) How do we do that? How do we do that? • Enhanced attenuation – In situ remedy that reduces mobility of contaminants to achieve goals that are sustainable for long time periods

Enhanced Attenuation Remedies Enhanced Attenuation Remedies Monitored Natural Attenuation (MNA): Let natural processes do the work and Vadose Zone Vadose Zone monit itor progress Contaminant Plume Enhanced Attenuation (EA): Saturated Zone Groundwater Flow Engineered remedy that increases attenuation capacity of aquifer Attenuation-based remedies leave contaminants in subsurface contaminants in subsurface In Situ Treatment • Require a high burden of proof that Zone contaminants will not re-mobilize and Groundwater Flow become a threat again become a threat again • Strategic design helps meet the burden of proof 4

The Problem: The Problem: SRS F SRS F- -area Basins area Basins Groundwater plume resulted from 30 years of discharge of low activity wastewater from an industrial nuclear facility. Major contaminants of concern are metals, uranium, tritium, and radioactive iodine.

F- F area Basins Remedial Timeline -area Basins Remedial T meline Basins Closed/Capped Pump-Treat 1988 1955 Present 1997 2003 Funnel-and-Gate/ Funnel and Gate/ 1991 1991 Waste Discharged to Basins Base Injection 6

F Area Basins Monitoring Network F- -Area Basins Monitoring Network Large number of well/sampling locations where groundwater is groundwater is sampled and analyzed Only a small number of locations are required by regulatory agreement agreement

Monitoring by Function Monitoring by Function Baseli line approach • Quarterly monitoring of contaminant concentration • Yield Yield limited limited insight insight into the conditions and processes into the conditions and processes that control plume stability and contaminant migration Monitoring by Function Add inexpensive measurements of controlling processes such as b bound dary conditi ditions and d geoch hemi ical l mas t ter variables to provide functional assessment to supplement analysis of a reduced number of groundwater samples – Hydrologic Boundary Conditions – Master Variables

Boundary Conditions Boundary Conditions Overall physical and hydrological Overall physical and hydrological Data Sources driving forces • Precipitation – Precipitation gauges and telemetry, satellite data, groundwater level Data types include meteorology, hydrology, monitoring geology, land d use, operati tion/remedi diati tion • Evapotranspiration – Landsat satellite data history, e.g. • Stream/River Flow – USGS databases, stream flow gauges, satellite data – changes in production of water from • P Precipitation chemistry (Acid rain, Hg i it ti h i t (A id i H well lls (process/potable/municipal/agricultural) deposition) – NADP maps, point monitoring) – changes in discharge of water to • Surface water (lakes, ponds, drainages, etc.) basins/streams, dams, etc. – Army Corps of Engineers, local authorities, – new infrastructure and construction etc. – discontinuation of active industrial • Pumping Wells (New and existing wells) – processes Local municipalities • Discharges (Industry outfalls etc ) – Local and Discharges (Industry outfalls etc.) Local and Generally easy to measure and often government agencies overlooked • Infrastructure/Construction -- Local and government agencies

Master V Master Va ariables riables Master Variables are the key variables that control the chemistry of the groundwater system –Redox variables (ORP, DO, chemicals) –pH –Specific Conductivity –Biological Community (Breakdown/decay products) – Temperature Temperature Existing sensors and tools to measure these variables inexpensively are commercially available 10

Field Demonstration of Field Demonstration of Approach Approach Technical Problem Technical Problem • How do you test a new paradig gm for long g-term monitoring without doing years of long-term monitoring? Approach Approach • Use monitoring data from a waste site with a lon g g histor y y of data and well characterized changes to boundary conditions and master variables • Identify key controlling variables and implement strategy Identify key controlling variables and implement strategy at a well characterized test bed

Groundwater Flow Through T Groundwater Flow Through Time me Operation Capped Water level measurements indicate distinct changes in fl flow pattern tt Precipitation predictive of water level in some wells Current Pump-Treat

Sensor Installation Sensor Installation SRNL-MS-2016-00108 13

Contaminants Through T Contaminants Through Ti ime me

Specific Conductance Specific Conductance as a Surrogate as a Surrogate 15

Complexities Complexities Lots of noise in the measurements Lots of “noise” in the measurements • Small water level changes cause significant changes in measurement of stratified plume. • Time scale of change – Daily, Seasonal, Climatic … • Different areas of the plume show different trends • Surrogate measurements seem to be robust but Surrogate measurements seem to be robust but calibration issues with sensors an issue How do you determine what is a significant change? • Determination of trigger levels for action Yikes !!! – What to Do?

Prediction Capability: ASCEM Prediction Capability: ASCEM Advanced Simulation Capability for Environmental Management

Virtual T rtual Testbed estbed How do you test a new paradigm for long term monitoring without doing years of monitoring?  Develop a virtual test bed using 3D reactive flow and transport model transport model

Flow/Transport Model Flow/T ransport Model Bea et al. (2013)

3D Mesh Development 3D Mesh Development Surface Seismic Method Wainwright et al. (2014)

3D Mesh for 3D Mesh for Artificial Barriers Artificial Barriers Meshing by LAGriD g y

Effect of Barriers on T Effect of Barriers on Tritium Plume itium Plume

Geochemistry Development Geochemistry Development Surface complexation, cation exchange • Complex geochemistry – pH D Depend dent t – Aqueous complexation Mineral dissolution/precipitation – – Surface complexation Surface complexation – Mineral dissolution/precipitation – Cation exchange – Decay Aqueous complexation (and more)

New Paradigm New Paradigm Big Da ta methods for real-time data analysis and early y wa rning g systems Virtual Test Bed: ASCEM modeling tool for predicting long-term performance New sensing technologies for automated remote continuous monitoring • In situ sensors, geophysics, fiber optics, UAVs Cloud Storage Computing phone tower h data logger & modem work computer In situ Sensors Artificial Neural Network well Big Data

Virtual test bed rtual test bed 1966 1966 1966 Top – Low-pH plume (pH> 4) Bottom – Uranium Plume Bottom Uranium Plume Vertical exaggeration=15X 25

What Now? What Now? Developing specific strategy for F-area • Master variables and sensor/well locations through time for different contaminants • Change in absorption/mobility for contaminants in system as pH evolves p e o es • Establish trigger levels for boundary conditions • Test hypotheses using virtual test bed • Develop recommendations for key geochemical events for complex plumes of metal and radionuclides • Investigate new methods for monitoring g that are multidimensional to focus on measurement of changes.

Environmental Data Management Environmental Data Management • QA/QC methods developed for - Pressure transducer data to measure water levels - Temperature data in vadose zone and groundwater groundwater RADIATION MONITORING - Meteorological data • QC flagging method to identify and correct erroneous data outside a reasonable range and Original data Filtered data occurrence of anomalous spikes (due to perturbations during (due to perturbations during water sampling events from monitoring wells). • QA/QC of location coordinates, QA/QC f l ti di t elevations and top of casings

Geophysical Subsurface Imaging Geophysical Subsurface Imaging - Electrical Resistivity Tomography Electrical Resistivity Tomography - Autonomous data collection and streaming Bulk electrical conductivity  Plume migration etc -

Fiber Optic T Fiber Optic Technologies echnologies • Autonomous Permafrost Thaw Detection P f t Th D t ti Distributed sensing – Temperature – Soil moisture Soil moisture – Acoustic properties – Chemistry (e.g., pH) Ajo-Franklin et al