Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region

EPA Grant Number: R827933C020
Subproject: this is subproject number 020 , established and managed by the Center Director under grant R825427
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Urban Waste Management and Research Center (University New Orleans)
Center Director: McManis, Kenneth
Title: Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region
Investigators: Sansalone, John , Cartledge, Frank K. , Tittlebaum, Marty
Current Investigators: Sansalone, John , Cartledge, Frank K. , Tittlbaum, Marty
Institution: Louisiana State University - Baton Rouge , University of New Orleans
EPA Project Officer: Lasat, Mitch
Project Period: July 1, 2000 through June 30, 2003
RFA: Urban Waste Management & Research Center (1998) RFA Text |  Recipients Lists
Research Category: Targeted Research

Objective:

This research is a bench-scale experimental study on the influence of cyclic interfacial redox conditions and resulting pH changes that result from variably high groundwater conditions typical of the Gulf Coast region. Therefore, an experimental model will be designed, fabricated, and instrumented to conduct in situ model measurements such as redox potential, pH, temperature, and conductivity. An experimental matrix will be developed as a function of water table conditions, soil type, time (number and duration of redox cycles simulating long-term seasonal geoenvironment), and position in and around the clay liner periphery. This bench-scale system also will be designed to permit sampling of leachate, clay liner, surrounding soil, and soil porewater. Three separate clay liner materials will be investigated: (1) bentonite, (2) kaolinite, and (3) native Louisiana clay. The surrounding soil will be typical of common soils with the variable high groundwater conditions of south Louisiana. The bench-scale experimental system also will be designed, fabricated, and instrumented for the purposes of quantifying changes in clay structure, mineralogy, and hydraulic properties to experimentally simulated conditions.

The second objective is to evaluate changes to mineralogy, structure, porosity, and fabric of the clay liner under different redox conditions and coupled pH changes. This will be experimentally conducted for a number of cases: Case I: This case will experimentally simulate moist yet unsaturated conditions, replicating drained aerobic conditions that can occur for landfill liners either (1) above the natural phreatic surface; or (2) above the lowered water table (and phreatic surface) as a result of engineered subsurface drainage; Case II: This case will experimentally simulate constant saturated anaerobic conditions typical of high water table conditions. Case I and II serve as controls and limiting aerobic and anaerobic conditions for a given set of experimental and soil parameters; and Case III: This case will experimentally simulate cyclic redox conditions with variable frequency and duration of the redox cycles. Based on both the scientific background and engineering requirements for a clay liner under cyclic redox conditions, clay liner analysis will include x-ray and x-ray absorption spectroscopy (EXAFS, XANES, x-ray microprobe) to provide data on chemical valence state and bonding influence on environmental behavior in a nondestructive manner. A particular advantage of the nondestructive character is that changes over time can be monitored as dynamic processes occur.

The final objective of the research is to assess the impact of cyclic redox conditions (Case III as compared with Case I and II) and commensurate pH changes on the mobilization and transport of heavy metal leachate through the clay liner. Lower redox conditions (anaerobic conditions) and decrease in pH lead to speciation changes, increased dissolution of immobilized or partitioned heavy metals, and therefore increased mobility of heavy metals. Redox (typically represented as Eh and measured in volts) and pH reactions are coupled reactions in the subsurface environment and as such, represent master variables for heavy metal speciation. The ability to identify equilibrium speciation in Eh-pH space from in situ Eh (redox) and pH measurements provides a valuable tool to assess fate and transport. As an example of a leachate heavy metal in geochemical environment influenced by redox changes and coupled pH changes, consider Cd speciation as a function of Eh and pH. Figure 1 demonstrates the importance of redox changes and associated pH changes. Liquid (pore water and leachate) and digested soil sample analyses taken as part of an experimental matrix will be analyzed for heavy metals with ICP-MS. Heavy metals of interest are amenable to XAS spectroscopy, and studies of surface interaction between metals and clay will be conducted.

Supplemental Keywords:

clay, heavy metals, speciation, oxidation-reduction, freundlich, isotherm, sorption partitioning., Scientific Discipline, INTERNATIONAL COOPERATION, Waste, Municipal, Civil/Environmental Engineering, Civil Engineering, Ecological Risk Assessment, Engineering, Environmental Engineering, Urban and Regional Planning, clay liners, landfill design, municipal waste, landfill operation, evaluation of leaching, municipal solid waste landfills, redox conditions, solid waste, municipal solid waste regulations

Progress and Final Reports:

  • 2001
  • 2002
  • Final Report

  • Main Center Abstract and Reports:

    R825427    Urban Waste Management and Research Center (University New Orleans)

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825427C001 Comprehensive Evaluation of The Dual Trickling Filter Solids Contact Process
    R825427C002 Issues Involving the Vertical Expansion of Landfills
    R825427C003 Deep Foundations on Brownfields Sites
    R825427C004 Ambient Particulate Concentration Model for Traffic Intersections
    R825427C005 Effectiveness of Rehabilitation Approaches for I/I Reduction
    R825427C006 Urban Solid Waste Management Videos
    R825427C007 UWMRC Community Outreach Multimedia Exhibit
    R825427C008 Including New Technology into the Investigation of Inappropriate Pollutant Entries into Storm Drainage Systems - A User's Guide
    R825427C009 Investigation of Hydraulic Characteristics and Alternative Model Development of Subsurface Flow Constructed Wetlands
    R825427C010 Beneficial Use Of Urban Runoff For Wetland Enhancement
    R825427C011 Urban Storm and Waste Water Outfall Modeling
    R827933C001 Development of a Model Sediment Control Ordinance for Louisiana
    R827933C002 Inappropriate Discharge to Stormwater Drainage (Demonstration Project)
    R827933C003 Alternate Liner Evaluation Model
    R827933C004 LA DNR - DEQ - Regional Waste Management
    R827933C005 Landfill Design Specifications
    R827933C006 Geosynthetic Clay Liners as Alternative Barrier Systems
    R827933C007 Used Tire Monofill
    R827933C008 A Comparison of Upflow Anaerobic Sludge Bed (USAB) and the Anaerobic Biofilm Fluidized Bed Reactor (ABFBR) for the Treatment of Municipal Wastewater
    R827933C009 Integrated Environmental Management Plan for Shipbuilding Facilities
    R827933C010 Nicaragua
    R827933C011 Louisiana Environmental Education and Resource Program
    R827933C012 Costa Rica - Costa Rican Initiative
    R827933C013 Evaluation of Cr(VI) Exposure Assessment in the Shipbuilding Industry
    R827933C014 LaTAP, Louisiana Technical Assistance Program: Pollution Prevention for Small Businesses
    R827933C015 Louisiana Environmental Leadership Pollution Prevention Program
    R827933C016 Inexpensive Non-Toxic Pigment Substitute for Chromium in Primer for Aluminum Sibstrate
    R827933C017 China - Innovative Waste Composting Plan for the City of Benxi, People's Rupublic of China
    R827933C018 Institutional Control in Brownfields Redevelopment: A Methodology for Community Participation and Sustainability
    R827933C019 Physico-Chemical Assessment for Treatment of Storm Water From Impervious Urban Watersheds Typical of the Gulf Coast
    R827933C020 Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region
    R827933C021 Characterizing Moisture Content Within Landfills
    R827933C022 Bioreactor Landfill Moisture Management
    R827933C023 Urban Water Issues: A Video Series
    R827933C024 Water Quality Modeling in Urban Storm Water Systems
    R827933C025 The Development of a Web Based Instruction (WBI) Program for the UWMRC User's Guide (Investigation of Inappropriate Pollutant Entries Into Storm Drainage Systems)
    R827933C027 Legal Issues of SSO's: Private Property Sources and Non-NPDES Entities
    R827933C028 Brownfields Issues: A Video Series
    R827933C029 Facultative Landfill Bioreactors (FLB): A Pilot-Scale Study of Waste Stabilization, Landfill Gas Emissions, Leachate Treatment, and Landfill Geotechnical Properties
    R827933C030 Advances in Municipal Wastewater Treatment
    R827933C031 Design Criteria for Sanitary Sewer System Rehabilitation
    R827933C032 Deep Foundations in Brownfield Areas: Continuing Investigation
    R827933C033 Gradation-Based Transport, Kinetics, Coagulation, and Flocculation of Urban Watershed Rainfall-Runoff Particulate Matter
    R827933C034 Leaching and Stabilization of Solid-Phase Residuals Separated by Storm Water BMPs Capturing Urban Runoff Impacted by Transportation Activities and Infrastructure
    R827933C035 Fate of Pathogens in Storm Water Runoff
    R87933C020 Influence of Cyclic Interfacial Redox Conditions on the Structure and Integrity of Clay Liners for Landfills Subject to Variable High Groundwater Conditions in the Gulf Coast Region