Final Report: An Electrochemical Method for Acid Mine Drainage Remediation and Metals Recovery

EPA Grant Number: R825549C025
Subproject: this is subproject number 025 , established and managed by the Center Director under grant R825549
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC (1989) - Great Plains/Rocky Mountain HSRC
Center Director: Erickson, Larry E.
Title: An Electrochemical Method for Acid Mine Drainage Remediation and Metals Recovery
Investigators: Walton, Clifford W.
Institution: University of Nebraska at Lincoln
EPA Project Officer: Hahn, Intaek
Project Period: March 1, 1990 through February 29, 1992
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (1989) RFA Text |  Recipients Lists
Research Category: Heavy Metal Contamination of Soil/Water , Land and Waste Management


The goal of this project was to obtain the necessary experimental information required to determine the feasibility of an electrodialytic ion exchange (EDIX) cell-based metal recovery system as applied to acid mine drainage (AMD), and potential co-application to electroplating rinse waters. This included the experimental measurement of the performance of a laboratory-scale EDIX cell and the membranes of which it is constructed when exposed to chemicals found in the acid mine water. Finally, a first economic evaluation of the process and its potential for scaleup to a portable prototype was to be completed.

Summary/Accomplishments (Outputs/Outcomes):

As a means for eliminating the problem of water contamination and resource loss caused by acid mine drainage, a new method for waste management has been proposed. The intent of the electrodialytic ion exchange (EDIX) cell is to minimize both of these problems. The design criteria is to produce a residual wastewater stream which would meet U.S. EPA effluent guidelines for metal content and a concentrated metal ion stream which could be further recovered by electrowinning. The process also has direct application to metal recovery from electroplating wastewaters.

The EDIX cell, a variation of an electrodialysis cell stack, contains chambers separated by alternating bipolar membranes and cation permeable membranes. A typical cation permeable membrane consists of a fluorosulphonate polymer with fixed negative groups which are part of the membrane's physical structure. A typical anion membrane consists of a polymer with quaternary amine groups as fixed positive charges. A bipolar membrane consists of a cation permeable membrane and an anion permeable membrane which are laminated together. In the bipolar membrane, water disassociates into hydrogen ions and hydroxide ions under the applied electric field.

The wastewater stream from mining operations would flow into the waste chamber where metal and hydrogen ions migrate across the cation permeable membrane into the recovery chamber. In the recovery chamber, the formation of hydroxide ions balance the positive ions that have migrated from the waste chamber through the cation permeable membrane. A typical system consists of an alternating series of these membranes in a filter press construction.

The water flowing from the waste chamber could be released to a neutralization plant and subsequently released to the environment as it would now meet Effluent Limitation Guidelines set by the U.S. EPA for heavy metal content. This neutralized stream might also be used effectively in irrigation. Thus, the proposed method minimizes losses of valuable resources and could reduce or eliminate the problems associated with significant sludge production by current treatment methods for acid mine drainage. Also, the process can potentially be constructed on a small scale, providing a portable reclamation unit. This has the additional benefit of demonstrating potential resource recovery, waste treatment and minimization for small businesses, such as electroplating job shops.

This research project was composed primarily of the evaluation of EDIX laboratory-cell performance for feasibility, with an approximate projection of economic performance of scaleup. Tests were performed using an electrodialysis cell stack purchased from Ionics, Inc. Bipolar membranes were purchased from WSI Technology (St. Louis, MO) and cation and anion membranes from Ionics, Inc. Membranes from Ionics, Inc., were also combined to form bipolar membranes. Test performance of the cell stacks was measured using simple sodium sulfate solutions, then iron-containing simulated acid mine drainage solutions. When precipitation occurred during iron tests, membranes were regenerated in accordance with manufacture's recommendations prior to reuse. This allowed a degree of cyclic membrane usage testing. Sample chemical analysis was conducted in UNL laboratories (sodium) and by the Lincoln Plating Company (Lincoln, NE) (iron) as an in-kind donation of services, as well as by ion-selective electrodes.

In addition to the laboratory testing, a more detailed literature review of existing and potential methods of treatment for acid mine drainage was initiated. This also included gathering articles with information on quality assurance of work related to AMD. To aid effective use of the growing number of references, a database was constructed of the bibliographic data and complete abstracts to allow for convenient searching for desired information.

Previously conducted process modeling studies of the EDIX cell applied to electroplating rinse waters (many having compositions similar to that of acid mine drainage) has shown that this approach may be feasible. The studies did reveal that the passage of the contaminated stream through a single cell of the stack is not expected to be sufficient to obtain the desired separation that would result in a clean water stream and a concentrated metal stream. The simple results show the possibility of removal of upward of 70% in a single pass. Constructing a cell with recycle and/or series operation may achieve the desired goal of higher removal rates.

Experiments with sodium sulfate and iron sulfate solutions have demonstrated substantial removal of metals from the waste stream. These tests show the applied potential causes a multiple increase of metal concentration in the recovered stream, with concentrations in the recovery stream up to 80 times that of the outlet waste stream for the sodium tests.

During the iron-containing tests, metal hydroxide precipitates formed due to the high concentration of hydroxide ions immediately adjacent to the anion membrane side of the bipolar membrane (from the desired water disassociation reaction). Some precipitation appeared in the anion membrane, possibly due to poor cation rejection by the anion membrane. Increased flow and lower recovery side inlet concentrations were tried in order to reduce precipitation. Significant improvement was not obtained. Thus the current process concept would not be feasible for iron tor other easily precipitated metals), though a process for on-site precipitation without an external chemical supply may be possible.

The American Electroplaters and Surface Finishers Society has funded a small 1992 Summer Research Grant to evaluate the recovery of nickel using the EDIX cell concept.

Technology Transfer: The results have been presented at professional meetings and at a workshop. They have also been communicated to industrial companies that have expressed interest in this research.

Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other subproject views: All 17 publications 4 publications in selected types All 3 journal articles
Other center views: All 904 publications 230 publications in selected types All 182 journal articles
Type Citation Sub Project Document Sources
Journal Article Hillier AC, Walton CW. Modeling electroplating rinse systems using equation-solving software. Plating and Surface Finishing 1991;78(11):72-75. R825549C025 (Final)
not available
Journal Article C.W. Walton, W.C. Mammel, K.J. Loos, T.J. Fink, T.A. Lewis and B.C. Mulinix, "Feasibility Testing of the EDIX Cell Concept for Metal Recovery from Acid Mine Drainage," Submitted to J. Cleaner Production (1992). R825549C025 (Final)
not available
Journal Article Walton CW, Loos KJ. Options for waste minimizating in the metal finishing waste electroplating. Plating and Surface Finishing 1992;79(11):8-14. R825549C025 (Final)
not available

Supplemental Keywords:

heavy metals, membrane separation, recovery, Scientific Discipline, Waste, Water, Ecosystem Protection/Environmental Exposure & Risk, Contaminated Sediments, Environmental Chemistry, Geochemistry, Remediation, Fate & Transport, Bioremediation, Ecology and Ecosystems, fate and transport, contaminant transport, migration, acid mine drainage, biodegradation, pesticides, contaminated sediment, membranes, metals recovery, adsorption, contaminated soil, biotechnology, contaminants in soil, bioremediation of soils, chemical kinetics, electrodialytic ion exchange, acid rock drainage (ARD), heavy metal contamination, phytoremediation, mining waste, contaminated soils, heavy metals, electrochemical methods

Relevant Websites: Exit

Progress and Final Reports:

Original Abstract
  • 1990

  • Main Center Abstract and Reports:

    R825549    HSRC (1989) - Great Plains/Rocky Mountain HSRC

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R825549C006 Fate of Trichloroethylene (TCE) in Plant/Soil Systems
    R825549C007 Experimental Study of Stabilization/Solidification of Hazardous Wastes
    R825549C008 Modeling Dissolved Oxygen, Nitrate and Pesticide Contamination in the Subsurface Environment
    R825549C009 Vadose Zone Decontamination by Air Venting
    R825549C010 Thermochemical Treatment of Hazardous Wastes
    R825549C011 Development, Characterization and Evaluation of Adsorbent Regeneration Processes for Treament of Hazardous Waste
    R825549C012 Computer Method to Estimate Safe Level Water Quality Concentrations for Organic Chemicals
    R825549C013 Removal of Nitrogenous Pesticides from Rural Well-Water Supplies by Enzymatic Ozonation Process
    R825549C014 The Characterization and Treatment of Hazardous Materials from Metal/Mineral Processing Wastes
    R825549C015 Adsorption of Hazardous Substances onto Soil Constituents
    R825549C016 Reclamation of Metal and Mining Contaminated Superfund Sites using Sewage Sludge/Fly Ash Amendment
    R825549C017 Metal Recovery and Reuse Using an Integrated Vermiculite Ion Exchange - Acid Recovery System
    R825549C018 Removal of Heavy Metals from Hazardous Wastes by Protein Complexation for their Ultimate Recovery and Reuse
    R825549C019 Development of In-situ Biodegradation Technology
    R825549C020 Migration and Biodegradation of Pentachlorophenol in Soil Environment
    R825549C021 Deep-Rooted Poplar Trees as an Innovative Treatment Technology for Pesticide and Toxic Organics Removal from Soil and Groundwater
    R825549C022 In-situ Soil and Aquifer Decontaminaiton using Hydrogen Peroxide and Fenton's Reagent
    R825549C023 Simulation of Three-Dimensional Transport of Hazardous Chemicals in Heterogeneous Soil Cores Using X-ray Computed Tomography
    R825549C024 The Response of Natural Groundwater Bacteria to Groundwater Contamination by Gasoline in a Karst Region
    R825549C025 An Electrochemical Method for Acid Mine Drainage Remediation and Metals Recovery
    R825549C026 Sulfide Size and Morphology Identificaiton for Remediation of Acid Producing Mine Wastes
    R825549C027 Heavy Metals Removal from Dilute Aqueous Solutions using Biopolymers
    R825549C028 Neutron Activation Analysis for Heavy Metal Contaminants in the Environment
    R825549C029 Reducing Heavy Metal Availability to Perennial Grasses and Row-Crops Grown on Contaminated Soils and Mine Spoils
    R825549C030 Alachlor and Atrazine Losses from Runoff and Erosion in the Blue River Basin
    R825549C031 Biodetoxification of Mixed Solid and Hazardous Wastes by Staged Anaerobic Fermentation Conducted at Separate Redox and pH Environments
    R825549C032 Time Dependent Movement of Dioxin and Related Compounds in Soil
    R825549C033 Impact of Soil Microflora on Revegetation Efforts in Southeast Kansas
    R825549C034 Modeling the use of Plants in Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances
    R825549C035 Development of Electrochemical Processes for Improved Treatment of Lead Wastes
    R825549C036 Innovative Treatment and Bank Stabilization of Metals-Contaminated Soils and Tailings along Whitewood Creek, South Dakota
    R825549C037 Formation and Transformation of Pesticide Degradation Products Under Various Electron Acceptor Conditions
    R825549C038 The Effect of Redox Conditions on Transformations of Carbon Tetrachloride
    R825549C039 Remediation of Soil Contaminated with an Organic Phase
    R825549C040 Intelligent Process Design and Control for the Minimization of Waste Production and Treatment of Hazardous Waste
    R825549C041 Heavy Metals Removal from Contaminated Water Solutions
    R825549C042 Metals Soil Pollution and Vegetative Remediation
    R825549C043 Fate and Transport of Munitions Residues in Contaminated Soil
    R825549C044 The Role of Metallic Iron in the Biotransformation of Chlorinated Xenobiotics
    R825549C045 Use of Vegetation to Enhance Bioremediation of Surface Soils Contaminated with Pesticide Wastes
    R825549C046 Fate and Transport of Heavy Metals and Radionuclides in Soil: The Impacts of Vegetation
    R825549C047 Vegetative Interceptor Zones for Containment of Heavy Metal Pollutants
    R825549C048 Acid-Producing Metalliferous Waste Reclamation by Material Reprocessing and Vegetative Stabilization
    R825549C049 Laboratory and Field Evaluation of Upward Mobilization and Photodegradation of Polychlorinated Dibenzo-P-Dioxins and Furans in Soil
    R825549C050 Evaluation of Biosparging Performance and Process Fundamentals for Site Remediation
    R825549C051 Field Scale Bioremediation: Relationship of Parent Compound Disappearance to Humification, Mineralization, Leaching, Volatilization of Transformaiton Intermediates
    R825549C052 Chelating Extraction of Heavy Metals from Contaminated Soils
    R825549C053 Application of Anaerobic and Multiple-Electron-Acceptor Bioremediation to Chlorinated Aliphatic Subsurface Contamination
    R825549C054 Application of PGNAA Remote Sensing Methods to Real-Time, Non-Intrusive Determination of Contaminant Profiles in Soils
    R825549C055 Design and Development of an Innovative Industrial Scale Process to Economically Treat Waste Zinc Residues
    R825549C056 Remediation of Soils Contaminated with Wood-Treatment Chemicals (PCP and Creosote)
    R825549C057 Effects of Surfactants on the Bioavailability and Biodegradation of Contaminants in Soils
    R825549C058 Contaminant Binding to the Humin Fraction of Soil Organic Matter
    R825549C059 Identifying Ground-Water Threats from Improperly Abandoned Boreholes
    R825549C060 Uptake of BTEX Compounds by Hybrid Poplar Trees in Hazardous Waste Remediation
    R825549C061 Biofilm Barriers for Waste Containment
    R825549C062 Plant Assisted Remediation of Soil and Groundwater Contaminated by Hazardous Organic Substances: Experimental and Modeling Studies
    R825549C063 Extension of Laboratory Validated Treatment and Remediation Technologies to Field Problems in Aquifer Soil and Water Contamination by Organic Waste Chemicals