Grantee Research Project Results

2001 Progress Report: Searching for Optimum Composition of Phosphogypsum: Fly ash: Cement Composites for Oyster Culch Materials

EPA Grant Number: R828598C759
Subproject: this is subproject number 759 , established and managed by the Center Director under grant R828598
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Gulf Coast HSRC (Lamar)
Center Director: Ho, Tho C.
Title: Searching for Optimum Composition of Phosphogypsum: Fly ash: Cement Composites for Oyster Culch Materials
Investigators: Rusch, Kelly Ann , Malone, Ronald F.
Institution: Louisiana State University
EPA Project Officer: Aja, Hayley
Project Period: September 1, 2000 through August 31, 2004
Project Period Covered by this Report: September 1, 2000 through August 31, 2001
RFA: Gulf Coast Hazardous Substance Research Center (Lamar University) (1996) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Targeted Research

Objective:

Phosphogypsum (PG) is a waste by-product of a wet manufacturing process in which phosphate ore is reacted with sulfuric acid to produce phosphoric acid The wet process has advantages of lower capital investment and production costs and greater flexibility of processing different grades of phosphate rock over the dry process. However, this process produces large volumes of PG containing trace metals and radioactive contaminants (Radium-226 and Uranium) that pose potential environmental problems. Radium-226 (Ra226) is of particular importance, with approximately 80% of that originally existing in the ore being concentrated in the PG by-product. Ra226 decays to radon gas (Rn222) with intense radiation capacity and a short half-life (3.8 days). Further decay results in emission of alpha (a) rays, which can do extensive damage to internal organs if digested. Consequently, radon is Classified as a cancer causing, radioactive gas. Emission concerns led to the promulgation of disposal/usage guidelines under the National Emission Standards for Hazardous Air Pollutants (NESHAP) and the National Emissions Standards for Radon Emission from PG Stacks. The current allowable disposal method for PG is stack piling. The annual production rate of PG ranges from 36.3 to 42.6 million metric tons in the United States. After water recovery and evaporation, large PG stack piles covering as much as 3 km² and up to 60 m high are formed. The total surface area covered by stack piles was about 34 km². There is an estimated on-ground inventory of over 630 million metric tons of phosphogypsum in Central and North Florida. The accumulation of PG stack piles causes significant space and environmental problems, placing increasing pressure on the fertilizer industry to find long-term solutions. Various alternatives for using PG beneficially are being sought to decrease risks to humans and the environment, to reduce the cost of storage, and to create an economic market for phosphogypsum products. One such alternative is the use of stabilized PG in the marine environment for aquatic resource enhancement and coastal restoration. This application provides one of the best means to minimize human radon gas exposure because the airborne vector of transmission is essentially eliminated, leaving bioaccumulation as the only potential transfer pathway. Preliminary laboratory data indicated that Portland type I cement stabilized PG composites support a diverse population of surface-attached, burrowing organisms and oysters, and that bioaccumulation is not a significant pathway of radium transfer. Most other proposed economic uses aimed at reducing the PG accumulation rate have potential problems associated with this fundamental issue of vector transmission. Researchers at Louisiana State University have focused on developing a composite that maintains physical integrity and has a long-term survival capacity in saltwater. Currently, composites using Portland type II cement and Class C fly ash have shown the most promise. To produce PG composites that can compete economically with other materials (mostly limestone or granite based), the Portland type II cement content must be less than 5% on a dry weight basis. The most recent research showed that the 62%:35%:3% PG:Class C fly ash: Portland type II cement composite can survive in seawater for more than two years. While this composition meets the less than 5% cement criterion, the admixture composition has not been optimized. Further optimization will likely lead to reduced production costs. Historically, Rangia cuneata clam shells were dredged and used as natural oyster culch material. Dredging has since been prohibited due to its associated water quality problems, thus eliminating clam shell as oyster culch material. The stockpiled clam shell supply has been exhausted, and Louisiana is currently transporting in limestone for this purpose at a cost of $13.5/ton (dose not include transportation cost). The immediate demand for shell material is roughly 80,000 tons of oyster culch per year in the Gulf Region based on the historic usage. Results to date show that specific PG: Class C fly ash: Portland type II cement composites can support a diverse population of surface attached and burrowing organisms, including oysters and barnacles. These composites have been in the field for more than two years. The estimated cost of 62%:35%:3% PG: Class C fly ash: Portland type II cement composites is $11.84/ton. This indicates the economic potential of using PG: Class C fly ash: Portland type II cement composites for oyster culch. With this new approach, two types of solid wastes can be converted into useful aquatic resource materials. The purpose of this project was to determine optimal ingredient combinations within the range of 20-35% Class C fly ash and 1-3% Portland type II cement for use as oyster culch. Calcium and sulfate effective diffusion coefficients are indicators of the long term stability of the stabilized PG composites. The objective of this study was to determine Ca²⁺ and SO4^2- effective diffusion coefficients for a series of ingredient combinations of stabilized PG composites. This research will provide baseline data for field seawater survivability analysis of selected optimum stabilized PG composites.

Progress Summary:

The log -log plots of J(Ca²⁺) versus time were used to estimate the Ca²⁺ effective diffusion coefficient De. Slopes of these regression equations indicate all slopes are close to theoretical diffusion slope of -0.5. Effective diffusion coefficient De ranged from 1.13 - 2.71X10^-13 m²/s, while effective diffusion depth ranged from 14.8 - 22.7 mm for 30 years submergence These values are comparable to the values from previous researches (10^-13 - 10^-14 m²/s) for PG: Class C fly ash: Portland type II cement composites. The log - log plots of J(SO4^2-) versus time were used to estimate the SO4^2- effective diffusion coefficient De. Slopes of these regression equations indicate all slopes are close to theoretical diffusion slope of -0.5. De ranged from 1.41 - 3.85x10^-13 m²/s, while effective diffusion depth ranged from 16.4 - 27.0 mm for 30 years submergence values are slight larger than the calcium effective diffusion coefficient obtained in this study. PG dissolves to form Ca²⁺ and SO4^2-. While both ions can be considered non-reactive, Ca²⁺ may undergo minimal reactions to form calcite. Sulfate, on the other hand undergoes no reactions, and therefore may be considered a better indicator of the PG dissolution process of the PG composites. Based on saltwater submergence experiments, 62%:35%:3% PG: Class C fly ash: Portland type II cement composites can survive for more than two years. Thus, the Ca²⁺ and SO4^2- effective diffusion coefficients for this composite will be used as the maximum allowable to determine optimum compositions. The effective diffusion coefficients for Ca²⁺ and SO4^2- are 1.5-1.6 x10^-13 m²/s. Considering the deviations, the maximum allowable value is selected to be 2.0x10^-13 m²/s. The estimated costs ranged from $9.34-11.00/ton The cost of previous optimum ingredient (62%:35%:3% PG: Class C fly ash: Portland type II cement) is $11.84/ton. This research may potentially reduce the cost of stabilized PG composites by $2.50/ton.

Supplemental Keywords:

Phosphogypsum, Stabilization, oyster culch, fly ash, cement, solid waste., Sustainable Industry/Business, RFA, Scientific Discipline, INTERNATIONAL COOPERATION, POLLUTION PREVENTION, TREATMENT/CONTROL, INDUSTRY, Waste, Hazardous, Waste Treatment, Industries, Environmental Chemistry, Hazardous Waste, waste reduction, Economics and Business, cleaner production/pollution prevention, Environmental Engineering, phosphogypsum, waste recovery, waste minimization, hazardous waste disposal, economic analysis, Production/Pollution Prevention, construction material, hazardous substance disposal, environmentally conscious manufacturing, product design, production processes, risk assessment, oyster culch materials, fly ash, bioaccumulation, alternative materials, chemically activated fly ash, construction industry, radium

Progress and Final Reports:

Original Abstract

2002

2003

Final Report

Main Center Abstract and Reports:

R828598    Gulf Coast HSRC (Lamar)

Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R822721C529 Environmentally Acceptable Endpoints: Risk Based Remediation Using Bioremediation
R822721C552 Degradative Solidification/Stabilization Technology for Chlorinated Hydrocarbons
R822721C569 Treatment and Product Recovery: Supercritical Water Oxidation of Nylon Monomer Manufacturing Waste
R822721C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R822721C626 Catalytic Hydroprocessing of Chlorinated Organics
R822721C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R822721C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R822721C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R822721C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R822721C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R822721C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R822721C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R822721C651 Adjustable Biopolymer Chelators for Cadmium, Lead and Mercury
R822721C653 New Electrochemically Smart Catalysts for Hazardous Waste Management and Development of Capillary Electrophoresis for Analysis of their Products
R822721C655 Soil Sampling in South Alabama Oil Fields
R822721C659 Subsurface Contamination Site Characterization via a Computer-Aided Visual Tool
R822721C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R822721C663 Soil Remediation with Ultra-High-Efficiency Hydrocyclones
R822721C669 Solid Acid Catalyzed Alkylation in Supercritical Fluids
R822721C679 Regeneration/Reactivation of Carbon Adsorbents by Radio Frequency (RF) Induction Heating
R822721C687 Improved Halogen Resistance of Catalytic Oxidation
R822721C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R822721C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R822721C700 Effects of Natural and Cyclic Variations on Contaminant Fate and Transport
R822721C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C620 Colloidal Fouling of Membranes: Implications in the Treatment of Textile Dye Wastes and Water Reuse
R826694C625 Enhanced Treatment of DNAPLs Contaminated Soils and Groundwater Using Biosurfactants: In-Situ Bioremediation
R826694C626 Catalytic Hydroprocessing of Chlorinated Wastes
R826694C627 The Interaction of Microbial Activity and Zero Valent Iron Permeable Barrier Technology
R826694C629 Biofiltration of BTEX in Petroleum-Contaminated Soil Remediation Off-Gas
R826694C630 Microbial Cometabolism of Recalcitrant Chemicals in Contaminated Air Streams
R826694C633 Catalyst Lifetime Studies for Chlorocarbon Steam Reforming
R826694C635 Electrokinetic/Surfactant-Enhanced Remediation of Hydrophobic Pollutants in Low Permeability Subsurface Environments
R826694C636 Transformation Reactions of Nitroaromatic and Nitrogen Heterocyclic Compounds on Granular Activated Carbon (GAC) Surfaces: Enhancement of GAC Adsorption in Natural and Engineered Environmental Systems
R826694C640 Environmentally Friendly Organic Synthesis in Supercritical Fluids
R826694C645 Development and Evaluation of an Integrated Model to Facilitate Risk-Based Corrective Action at Superfund Sites
R826694C651 Adjustable Biopolymer Chelators for Cadmium, Lead, and Mercury Remeidation
R826694C659 Subsurface Contamination Site characterization Via a Computer-Aided Visual Tool
R826694C661 New Insoluble supports for Protein Immobilization for Use in Metalloprotein Affinity Metal Chromatography
R826694C669 Solid Acid Catalyzed Alkylation in Supercritical Reaction Media
R826694C679 Regeneration and Reactivation of Carbon Adsorbents by Radio Frequency Induction Heating
R826694C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R826694C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R826694C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R826694C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R826694C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R826694C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R826694C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R826694C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R826694C731 Development and Application of a Real-Time Optical Sensor for Atmospheric Formaldehyde
R826694C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C001 Field Study Abstract: A Model of Ambient Air Pollution in Southeast Texas Using Artificial Neural Network Technology
R828598C002 Hollow Fiber Membrane Bioreactors for Treating Water and Air Streams Contaminated with Chlorinated Solvents
R828598C003 Fugitive Emissions of Hazardous Air Pollutants from On-Site Industrial Sewers
R828598C004 Biofiltration Technology Development
R828598C005 A Risk-Based Decision Analysis Approach for Aquifers Contaminated with DNAPLs
R828598C006 In-Situ Remediation for Contaminated Soils Using Prefabricated Vertical Drains
R828598C007 Membrane Technology Selection System for the Metal Finishing Industry
R828598C008 Sequential Environments for Enhanced Bioremediation of Chlorinated Aliphatic Hydrocarbons
R828598C009 Waste Minimization in the Magnetic Tape Industry: Waterborne Coating Formulations for Magnetic Tape Manufacture
R828598C010 Soil Remediation by Agglomeration with Petroleum Coke
R828598C011 Recovery of Dilute Phosphoric Acid in Waste Streams Using Waste Gas Ammonia: The Regenerative MAP/DAP Process
R828598C012 Stochastic Risk Assessment for Bioremediation
R828598C013 Selective Removal of Heavy Metals from Wastewater by Chelation in Supercritical Fluids
R828598C014 Optimization of Treatment Technologies for Detoxification of PCB Contaminated Soils
R828598C015 Wastewater Remediation by Catalytic Wet Oxidation
R828598C016 Permanence of Metals Containment in Solidified and Stabilized Wastes
R828598C017 Combustion Enhancement by Radial Jet Reattachment - Low Generation of Hazardous Gases and High Thermal Efficiency
R828598C018 A Process To Convert Industrial Biosludge and Paper Fines to Mixed Alcohol Fuels
R828598C019 Homogeneous Catalysis in Supercritical Carbon Dioxide
R828598C020 Ultrasonic Enhancement of the Removal of Heavy Metals
R828598C021 The Binding Chemistry and Leaching Mechanisms of Advanced Solidification/Stabilization Systems for Hazardous Waste Management
R828598C022 Development of an Air-Stripping and UV/H2O2 Oxidation Integrated Process To Treat a Chloro-Hydrocarbon-Contaminated Ground Water
R828598C023 A Comparative Study of Siting Opposition in Two Counties
R828598C024 Sonochemical Treatment of Hazardous Organic Compounds II: Process Optimization and Pathway Studies
R828598C025 Laser Diagnostics of the Combustion Process within a Rotary Kiln Incinerator
R828598C026 Use of Inorganic Ion Exchangers for Hazardous Waste Remediation
R828598C027 Kaolinite Sorbent for the Removal of Heavy Metals from Incinerated Lubricating Oils
R828598C028 Destruction of Chlorinated Hydrocarbons in Process Streams Using Catalytic Steam Reforming
R828598C029 Integrated Process Treatment Train (Bioremediation {Aerobic/Anaerobic} and Immobilization) for Texas Soils Contaminated with Combined Hazardous Wastes
R828598C030 Photo-Oxidation by H2O2/VisUV of Off-Gas Atmospheric Emissions from Industrial and Environmental Remediation Sources
R828598C031 Concentrated Halide Extraction and Recovery of Lead from Soil
R828598C032 Biodegradable Surfactant for Underground Chlorinated Solvent Remediation
R828598C033 A Software Guidance System for Choosing Analytical Subsurface Fate and Transport Models Including a Library of Computer Solutions for the Analytical Models
R828598C034 Hydrodynamic Modeling of Leachate Recirculating Landfill
R828598C035 Measurement of Oxygen Transfer Rate in Soil Matrices
R828598C036 Sorbent Technology for Multipollutant Control During Fluidized Bed Incineration
R828598C037 Pollution Prevention by Process Modification Using On-Line Optimization
R828598C038 Pollution Prevention by Process Modification
R828598C039 Water Solubility and Henry's Law Constant
R828598C040 Transferring Technical Information on Hazardous Substance Research by Publishing on the World Wide Web
R828598C041 Stress Protein Responses to Multiple Metal Exposure in Grass Shrimp
R828598C042 Life-Cycle Environmental Costing for Managing Pollution Prevention in the Chemical and Petroleum Refining Industries: A Cross-Border Approach
R828598C687 Improved Halogen Resistance of Catalytic Oxidation Through Efficient Catalyst Testing
R828598C696 Phytoremediation and Bioremediation of Land Contaminated By PAHs, PCBs, and TNT
R828598C697 Fundamental and Kinetic Investigation of Sorbent Technology for Optimum Mercury Emission Control
R828598C700 Effects of Natural Cyclic Variations on Contaminated Fate and Transport
R828598C703 Enhancement of DNAPL Dissolution Rates by Dechlorinating Anaerobes
R828598C705 A Pilot Plant for Producing Mixed Ketones from Waste Biomass
R828598C722 The Effects of an Oily-Phase on VOC Emissions from Industrial Wastewater
R828598C724 Mercury Removal from Stack Gas by Aqueous Scrubbing
R828598C725 Transport, Fate and Risk Implications of Environmentally Acceptable Endpoint Decisions
R828598C731 Development and Application of a Real Time Optical Sensor for Atmospheric Formaldehyde
R828598C734 An Advanced System for Pollution Prevention in Chemical Complexes
R828598C743 Field Demonstration of Ultrasound Enhancement of Permeable Treatment Walls
R828598C744 Optical Fibers Coated With Titania Membrane/UV-Generating Crystal in a Distributed-Light Photoreactor for VOC Oxidation
R828598C749 Characterization and Modeling of Indoor Particulate Contaminants In a Heavily Industrialized Community
R828598C753 Adsolubilization and Photocatalysis in a Semiconducting Monolithic Reactor for Wastewater Treatment
R828598C754 Remote Detection of Gas Emissions in Industrial Processes
R828598C759 Searching for Optimum Composition of Phosphogypsum: Fly ash: Cement Composites for Oyster Culch Materials
R828598C761 Development of a Phytologically-Based Biosorptive Water Treatment Process
R828598C766 Chlorinated Solvent Impact and Remediation Strategies for the Dry Cleaning Industry
R828598C769 Soil/Sediment Remediation by Hot Water Extraction Combined with In-Situ Wet Oxidation
R828598C771 Fluoracrylate Polymer Supported Ligands as Catalysts for Environmentally Benign Synthesis in Supercritical Fluids
R828598C774 The Feasibility of Electrophoretic Repair of Impoundment Leaks
R828598C777 Surfactant Enhanced Photo-oxidation of Wastewaters
R828598C778 Stationary Power Generation Via Solid Oxide Fuel Cells: A Response to Pollution and Global Warming
R828598C786 Photocatalytic Recovery of Sulfur and Hydrogen From Hydrogen Sulfide
R828598C787 Biosurfactant Produced from Used Vegetable Oil for removal of Metals From Wastewaters and Soils
R828598C789 Genetic Engineering of Enzymatic Cyanide Clearance
R828598C791 Characterizing the Intrinsic Remediation of MTBE at Field Sites
R828598C799 Simultaneous Water Conservation/Recycling/Reuse and Waste Reduction in Semiconductor Manufacturing
R828598C801 Building Defined Mixed Cultures To Biodegrade Diverse Mixtures Of Chlorinated Solvents
R828598C802 Engineering of Nanocrystal Based Catalytic Materials for Hydroprocessing of Halogenated Organics
R828598C807 Commercial Demonstration of Hydrogen Peroxide Injection to Control NOx Emissions from Combustion Sources
R828598C809 Evaluating Source Grouting and ORC for Remediating MTBE Sites
R828598C810 Application of Total Cost Assessment To Process Design In the Chemical Industry
R828598C846 Quantitative Demonstration of Source-Zone Bioremediation in A Field-Scale Experimental Controlled Release System