Use of a New Leaching Test Framework for Evaluating Alternative Treatment Processes for Mercury Contaminated Mixed Waste (Hazardous and Radioactive)

EPA Grant Number: R825511C014
Subproject: this is subproject number 014 , established and managed by the Center Director under grant R825511
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (1989) - Northeast HSRC
Center Director: Sidhu, Sukh S.
Title: Use of a New Leaching Test Framework for Evaluating Alternative Treatment Processes for Mercury Contaminated Mixed Waste (Hazardous and Radioactive)
Investigators: Kosson, David S. , Mattus, Catherine H. , Sanchez, Florence
Institution: Vanderbilt University , Oak Ridge National Laboratory
EPA Project Officer: Hahn, Intaek
Project Period: November 1, 1999 through May 31, 2001
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text |  Recipients Lists
Research Category: Hazardous Substance Research Centers , Land and Waste Management


Leaching protocols that address the limitations of the TCLP have been under development through coordinated parallel efforts in the United States and Europe. These protocols have been based on measurement of intrinsic leaching properties of a material and using the testing results in conjunction with assumed management scenarios and mass transfer models to estimate release of constituents of potential concern (COPC) over a defined time period. The Department of Energy (DOE) is responsible for extensive soil remediation and disposal of wastes that contain both mercury and radionuclides. The BDAT process specified for wastes containing elemental mercury is thermal desorption and reclaimation of mercury for recycling prior to waste disposal. However, mercury recovered from mixed waste cannot be recycled because of the potential for radionuclide contamination and the absence of a de minimis threshold for regulatory control of materials containing radionuclides produced by nuclear reactors under DOE control. Thus, in conjunction with USEPA, a DOE working group focused on management of mercury containing mixed waste, is seeking to define alternative treatment processes as acceptable as BDAT for these types of wastes. To achieve this goal, a side-by-side comparison of five vendor provided treatment processes is being carried out on two contaminated soils from Brookhaven National Laboratory. The specific objectives of this NHSRC research are to (i) evaluate a new framework for evaluating leaching of wastes for use in assessing the efficacy of potential treatment process for mixed wastes (radioactive and hazardous) that contain mercury, and (ii) use test results to compare the efficacy of the potential treatment processes when applied to a single prototype waste type.


The following major tasks have been identified for this project:
1. Laboratory testing on (i) two mercury contaminated soils (~ 4500 ppm) containing radionuclides (americium-241 in one case and europium-152 in the other) and (ii) the same two soils treated by each candidate treatment process (i.e., Sepradyne's thermal desorption with mercury recovery, BNL's encapsulation and amalgamation with a sulfur polymer cement and two vendor supplied solidification/stabilization processes).
2. Chemical analyses of solid samples and laboratory extracts generated during the protocol testing.
3. Quality assurance and quality control.
4. Data management and interpretation.

Laboratory testing (i.e., determination of constituent availability, solubility as a function of pH, mass transfer rate) is being carried out at Oak Ridge National Laboratory (ORNL) under subcontract to Vanderbilt University. The vendors (i.e., BNL, Sepradyne, Allied Technology Group and Nuclear Fuel Services) provided samples of the untreated soil they used as well as the treated soil they generated via the application to their processes. Thus, samples being tested under the new set of protocols are: (i) subsamples of the untreated soils treated during the different process demonstrations (ii) the two mercury contaminated soils treated by Sepradyne's thermal treatment, (iii) the mercury contaminated soil containing americium treated by S/S using sulfur polymer cement, (iv) the mercury contaminated soil containing europium treated by S/S using Portland cement (Allied Technology group) and (v) the mercury contaminated soil containing americium treated by S/S using proprietary additives (Nuclear Fuel Services).

For all of these samples, total content analyses on metals and mercury have been completed. As a baseline, a modified TCLP test was performed on each sample. As a first phase, the solubility and release as a function of pH (RU-SR002) protocol was set as a high priority and run on all the samples described above. Metals analyses by ICP and mercury analyses by CVAA on all the generated leachates have been performed. However, radionuclide analyses are still pending. Data generated to date (i.e., pH and mercury solubility or release) have been transcribed into Excel spreadsheet tables and plotted in accordance with the specific leaching procedure.

Results to date have shown different behaviors of solubility and release as a function of pH depending on the treatment process. Thus, a significant decrease of mercury solubility and release was observed with the Sepradyne's thermal desorption process within all the pH range. For the BNL's encapsulation and almagation with a sulfur polymer cement, while slightly less, no significant change in mercury solubility and release could be observed within the pH range of 4 to 13. For the ATG's Portland cement S/S process, although a significant decrease was observed within the pH range of 9 to 13, a significant increase was observed within the pH range of 4 to 7. For both untreated and treated soils, TCLP provided mercury release as much as one to two orders of magnitude lower than the release that would occur under the natural pH of the waste, indicating that TCLP underestimated the leachability of mercury.

Expected Results:

The use of testing results from leaching protocols based on measurement of intrinsic leaching properties of a material in conjunction with mass transfer models allows comparison of estimated release for a variety of management scenarios, including consideration of local conditions (e.g., infiltration and site-specific design) and direct comparison of different treatment processes under diverse potential environmental conditions (e.g., over a range of field pHs). Thus, the new leaching test framework would facilitate greater flexibility and more appropriate options for waste management. Although testing costs would initially increase, overall waste management costs would decrease if the regulatory implementation of the framework allowed for more cost effective management options while maintaining environmental protection. In many cases, environmental protection would be improved because testing results would allow decisions based on realistic estimates of constituent leaching rather than on test results with little significance relative to the actual management scenario. Treatment processes would focus on decreasing actual release rather than passing an arbitrary test. Use of testing that provides realistic release estimates also would facilitate improved risk assessment for this exposure pathway. This NHSRC research provides a unique opportunity to evaluate an alternative testing framework for a complex waste stream and a variety of treatment options.

Supplemental Keywords:

TCLP, Leaching, Solid Wastes, Heavy Metals, Mercury., RFA, Scientific Discipline, Waste, Water, Contaminated Sediments, Environmental Chemistry, Analytical Chemistry, Hazardous Waste, Chemistry and Materials Science, Ecological Risk Assessment, Hazardous, Mercury, complex mixtures, hazardous waste management, sediment treatment, TCLP, radionuclides, contaminated sediment, contaminated soil, leaching of toxic metals, treatment, mercury recovery, waste management, metal wastes, heavy metals, leachate, radioactive waste

Progress and Final Reports:

  • 2000
  • Final Report

  • Main Center Abstract and Reports:

    R825511    HSRC (1989) - Northeast HSRC

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825511C001 Development of Mechanisms and Kinetic Models on Formation of Polychlorinated Dibenzo-p-Dioxins and Dibenzofurans from Aromatic Precursors
    R825511C002 Real-Time Monitoring and Control of Emissions from Stationary Combustors and Incinerators
    R825511C003 Development of Sampling Systems for Continuous Monitoring of Volatile Organic Compounds (VOCs)
    R825511C004 Investigation into the Effectiveness of DNAPL Remediation Strategies in Fractured Media
    R825511C005 Advanced Leak Detection and Location Research: Extending the SERDP-funded Technical Base
    R825511C006 Three-Dimensional Geostatistical Site Characterization with Updating
    R825511C007 Anaerobic Biodegradation of PAHs in Soils and Dredged Sediments: Characterizing, Monitoring and Promoting Remediation
    R825511C008 Substrate Accelerated Death and Extended Lag Phases as Causes of the Recalcitrance of Halogenated Compounds in Anoxic Environments
    R825511C009 Fate and Transport of Nonionic Surfactants
    R825511C010 In Situ Degradation of Petroleum Hydrocarbons and PAHs in Contaminated Salt Marsh Sediments
    R825511C011 Design and Operation of Surfactant-Enhanced Bioslurry Reactors
    R825511C012 Experimental Study of Overland Transport of Cryptosporidium parvum Oocysts
    R825511C013 Development of a Framework for Evaluation of Leaching from Solid Waste
    R825511C014 Use of a New Leaching Test Framework for Evaluating Alternative Treatment Processes for Mercury Contaminated Mixed Waste (Hazardous and Radioactive)
    R825511C015 Field Pilot Test of In Situ Ultrasonic Enhancement Coupled With Soil Fracturing to Detoxify Contaminated Soil
    R825511C016 Development of Sampling Systems for Continuous Monitoring of Volatile Organic Compounds (VOCs)
    R825511C017 Field Demonstration of the Use of Reactive Zero-Valence Iron Powder to Treat Source Zone Sites Impacted by Halogenated Volatile Organic Chemicals
    R825511C018 Technology Transfer of Continuous Non-Methane Organic Carbon (C-NMOC) Analyzer
    R825511C019 Field Sampling and Treatability Study for In-Situ Remediation of PCB's and Leachable Lead with Iron Powder
    R825511C020 Experimental and Modeling Studies of Chlorocarbon Incineration, PIC Formation, and Emissions Control
    R825511C021 Experimental Studies and Numerical Modeling of Turbulent Combustion During Thermal Treatment of Hazardous Wastes: Applied Research for the Generation of Design and Diagnostic Tools
    R825511C022 Electrochemical Sensor for Heavy Metals in Groundwater - Phase IV
    R825511C023 Novel Molecular Tools for Monitoring In-Situ Bioremediation
    R825511C024 Surfactant-Enhanced Bioremediation of Soils in the Presence of an Organic Phase
    R825511C025 Enhanced Microbial Dechlorination of PCBs and Dioxins in Contaminated Dredge Spoils
    R825511C026 Toward A Risk-Based Model for Bioremediation of Multicomponent NAPL Contaminants
    R825511C027 Removal and Recovery of VOCs and Oils from Surfactant-Flushed Recovered Water by Membrane Permeation
    R825511C029 Field Pilot Test of In-Situ Ultrasonic Enhancement Coupled With Soil Fracturing to Detoxify Contaminated Soil in Cooperation with McLaren/Hart Environmental Engineers at the Hillsborough, NJ Site
    R825511C030 In-Situ Field Test of Electroremediation of a Chromate-Contaminated Site in Hudson County, New Jersey
    R825511C031 Electrokinetic Removal of Heavy Metals and Mixed Hazardous Wastes from Partially and Fully Saturated Soils
    R825511C032 Effects of Clay Charge and Confining Stresses on Soil Remediation by Electroosmosis
    R825511C033 Assessment of Surfactant Enhanced Bioremediation for Soils/Aquifers Containing Polycyclic Aromatic Hydrocarbons (PAHs)
    R825511C034 In-Situ Bioremediation of Organic Compounds: Coupling of Mass Transfer and Biodegradation
    R825511C035 Investigation into the Effectiveness of DNAPL Remediation Strategies in Fractured Media
    R825511C036 Field Pilot Scale Demonstration of Trench Bio-Sparge: An In-Situ Groundwater Treatment Technology
    R825511C037 In-Situ Reductive Dehalogenation of Aliphatic Compounds by Fermentative Heterotrophic Bacteria
    R825511C038 The Effect of Carbon-Nitrogen Ratios on Bacterial Transport and Biodegradation Rates In Soils
    R825511C039 Ultrasonic Enhancement of Soil Fracturing Technologies for In-Situ Detoxification of Contaminated Soil
    R825511C040 Full Field Demonstration of Integrated Pneumatic Fracturing and In-Situ Bioremediation
    R825511C041 Determination of Adsorption and Desorption Behavior of Petroleum Products on Soils
    R825511C042 Evaluation of the Potential for Complete Bioremediation of NAPL-Contaminated Soils Containing Polycyclic Aromatic Hydrocarbons (PAHs)
    R825511C043 Characterization of Subsurface NAPL Distributions at Heterogeneous Field Sites
    R825511C044 Development of a Thermal Desorption Gas Chromatograph/Microwave Induced Plasma/Mass Spectrometer (TDGC/MIP/MS) for On-site Analysis of Organic and Metal Contaminants
    R825511C045 Using Trainable Networks for a Three-dimensional Characterization of Subsurface Contamination
    R825511C046 Application of Advanced Waste Characterization to Soil Washing and Treatment
    R825511C047 Electrochemical Sensor for Heavy Metals in Groundwater Phase III
    R825511C048 Improved Luminescence Sensors for Oxygen Measurement
    R825511C049 Preconcentration, Speciation and Determination of Dissolved Heavy Metals in Natural Waters, using Ion Exchange and Graphite Furnace Atomic Absorption Spectrometry
    R825511C050 Experimental and Modeling Studies of Chlorocarbon Incineration and PIC Formation
    R825511C051 PIC Emission Minimization: Fundamentals and Applications
    R825511C052 Project Title: Development of a Two Stage, Pulse Combustion, VOC Destruction Technology
    R825511C053 Development of Sampling Systems for Continuous Monitoring of Volatile Organic Compounds (VOCs)
    R825511C054 FTIR Analysis of Gaseous Products from Hazardous Waste Combustion
    R825511C055 Toxic Metals Volatilization for Waste Separation and Real-time Metals Analyses
    R825511C056 Mixed Metal Removal and Recovery by Hollow Fiber Membrane-Based Extractive Adsorber
    R825511C057 Removal of Volatile Organic Compounds (VOCs) from Contaminated Groundwater and Soils by Pervaporation
    R825511C058 Simultaneous SO2/NO Removal/Recovery by Hollow Fiber Membrane
    R825511C059 Superfund Sites and Mineral Industries Method
    R825511C060 Soil Washing of Mixed Organics/Metal Contamination
    R825511C061 Removal of Cesium, Strontium, Americium, Technetium and Plutonium from Radioactive Wastewater
    R825511C062 Development of a Method for Removal of Nonvolatile Organic Materials from Soil using Flotation
    R825511C063 Recovery of Evaporative Fuel Losses by Vapor Permeation Membranes
    R825511C064 Surfactant Selection Protocol for Ex Situ Soil Washing
    R825511C065 Biofiltration for the Control of Toxic Industrial VOCs Emissions
    R825511C066 Catalytic Oxidation of Volatile Organic Compounds in Water
    R825511C067 Soil Washing for Remediating Metal Contaminated Soils
    R825511C068 Aqueous Absorption and Kinetics of NO by Strong Oxidizing Agents
    R825511C069 Remediation of Dredging Spoils
    R825511C070 Freeze Concentration for Zero-Effluent Processes
    R825511C071 Life Cycle/Pollution Prevention Response to Executive Order 12856
    R825511C072 Faster Better, Cheaper Hazardous Waste Site Characterization and Cleanup: an Adaptive Sampling and Analysis Strategy Employing Dynamic Workplans
    R825511C073 Development of a Comprehensive Computer Model for the Pneumatic Fracturing Process
    R825511C074 Technology Demonstration and Validation of CFAST Field Analytical Instrumentation for Use in Hazardous Waste Site Characterization, Clean-up and Monitoring
    R825511C075 XFLOW: Training Software Simulating Contaminant Site Characterization and Remediation