Dioxins
Treatment Technologies
When cleanup began at the Times Beach, Missouri Superfund site in the 1980s, rotary kiln incineration was the only fully demonstrated, commercially available and permitted technology for cleaning up dioxin in soil. Since then, additional remediation technologies for the cleanup of dioxin-contaminated soil and sediments have been researched and developed, but several of the accepted techniques still rely on thermal destruction, which is energy intensive. Heat-based destruction techniques for treating dioxin-contaminated soil and debris include incineration, thermal desorption, and vitrification. Incineration at temperatures above 1200°C is considered the most effective way of destroying dioxins. Thermal desorption, which operates at lower temperature range to vaporize dioxins, is also commonly used. A large-scale cleanup was completed in 2018 at the Bien Hoa Airport in Danang, Vietnam where nearly 95,000 m3 were excavated and treated with thermal desorption (USAID, 2018). Vitrification is largely a stabilization technique that uses very high temperatures to melt contaminated soil. When subsequently cooled, it forms a glassy mass that traps contaminants and reduces their mobility.
Bioremediation and phytoremediation are attractive options for cleaning up dioxin-contaminated soil, as they are less energy intensive than other technologies (Research and bench-scale studies are documented in the resources below.) However, their applicability and effectiveness in the field is being assessed. The application of activated carbon to contaminated soil and sediment also shows promise for mitigating the bioavailability of dioxins and reducing entry into the food chain. Additional thermal and non-thermal technologies that have been researched and tested include base-catalyzed decomposition, photodegradation with ultraviolet light, supercritical water oxidation, and others.
Containment is an option for soil and sediment with residual contamination that does not meet cleanup standards following treatment. Caps constructed over the contaminated soil or sediment minimize exposure and risk, prevent vertical infiltration of water and leachate, and control vapor and odor emissions. However, they do not destroy dioxins.
References:
U.S. Congress, Office of Technology Assessment, 1991. 
Dioxin Treatment Technologies. OTA-BP-O-93..
U.S. Agency for International Development (USAID), 2018. Performance Evaluation of USAID'S Environmental Remediation at Danang Airport Office of Economic Growth, Education and Environment (E3), Office of Economic Policy, 110 pp.
The resources below provide further information on various technologies, including some demonstrations and full-scale applications. Research projects on dioxin remediation are also included.
Technology Reviews
Soil Washing for the Remediation of Dioxin-Contaminated Soil: A Review
Tran, H.T., C. Lin, H.G. Hoang, X.T. Bui, V.G. Le, and C.T. Vu.
Journal of Hazardous Materials 421:126767(2022) [Abstract]
Approximately 200 documents were involved in this review to summarize up-to-date scientific achievements of soil washing technology to remediate dioxin-contaminated soil, including the mechanisms, advantages, and limitations of physical separation techniques and washing solutions used for chemical extraction. Froth flotation is very promising for field-scale soil washing, whereas organic solvents show high removal efficiencies (≤99%) of dioxins from contaminated soil. Combining physical separation and chemical extraction can help enhance dioxin removal efficiency, reducing energy consumption and cost. Among available remediation technologies for dioxin-contaminated soil, soil washing is truly promising since it has shown high removal efficiency (66-99% different remediation scales) with reasonable cost ($46-250 USD/tonne). However, the washed solution and VOCs generated during the process remain a concern and should be addressed in future research.
Treatment of Dioxin Contaminated Soils: Literature Review and Remediation Method Development
Strandberg, J., H. Oden, R.M. Nieto, and A. Bjork.
Swedish Environmental Research Institute, IVL Report B1993, 83 pp, Nov. 2011
This literature review takes a look at documented soil remediation techniques tested for dioxins and includes bench- and lab-scale experimental results conducted to test the hypothesis that dioxins can be extracted into an aqueous solution and then oxidized to eliminate contaminants.
Reference Guide to Non-combustion Technologies for Remediation of Persistent Organic Pollutants in Soil, Second Edition - 2010
U.S. EPA, Office of Solid Waste and Emergency Response (EPA 542-R-09-007) 2010.
This second edition of U.S. EPA's 2005 report provides a high-level summary of information on the applicability of existing and emerging non-combustion technologies for the remediation of persistent organic pollutants (POPs) in soil. Since the publication of this report in 2005, nine additional chemicals have been listed in the Stockholm Convention; this brings the total number of chemicals currently listed as POPs under the Stockholm Convention to 21. In addition, three POPs are currently under consideration.
Methods for Treating Soils Contaminated with Polychlorinated Dibenzo-p-Dioxins, Dibenzofurans, and Other Polychlorinated Aromatic Compounds
P. Haglund
Ambio 36(6):467-474(2007)
This review summaries methods for treating soils contaminated with polychlorinated aromatic compounds, including PCDD/Fs, including containment and incineration, as well as alternative techniques such supercritical water oxidation, base-catalyzed decomposition, steam distillation, and various extraction techniques, such as solvent and liquefied gas and subcritical water extraction.
Review of Emerging, Innovative Technologies for the Destruction and Decontamination of POPs and the Identification of Promising Technologies for Use in Developing Countries
Univ. of Auckland, New Zealand. United Nations Environment Programme, Global Environmental Facility, Scientific and Technical Advisory Panel. GF/8000-02-02-2205, 138 pp, 2004.
The proceedings of the 2003 Scientific and Technical Advisory Panel of the Global Environmental Facility United Nations Environment Programme workshop were developed into a review of approximately 50 existing non- combustion technologies for the destruction of persistent organic pollutants (POPs). Each technology was placed into one of five categories: (1) commercialized technologies with considerable experience, (2) technologies near or at the start of commercialization, (3) promising technologies, (4) technologies requiring significant research, and (5) technologies unlikely to be applicable for destruction of POPs stockpiles. Five emerging and promising technologies were identified for further evaluation and funding for rapid commercialization (ball milling, the GeoMelt™ process, mediated electrochemical oxidation via CerOx, mediated electrochemical oxidation via the AEA Silver II Process, and catalytic hydrogenation
Polychlorodibenzo-p-Dioxin and Polychlorodibenzo-Furan Removal and Destruction
Stavan Patel, Michael D. Kaminski, Luis Nunez
Argonne National Laboratory, ANL-CMT-03/4, 17 pp, 2003.
Report provides an overview of technologies used to destroy or separate dioxins and furans from environmental samples as background for developing a magnetic particles technology for large-scale, cost-effective destruction of dioxins and furans in fresh water, sludge, or soil.
Bioremediation and Phytoremediation
Aerobic Bacterial Transformation and Biodegradation of Dioxins: A Review
Bioresources and Bioprocessing 7:7(2020)
Saibu, S., S.A. Adebusoye, and G.O. Oyetibo.
Bacterial aerobic degradation of dibenzofurans and dibenzo-p-dioxins can occur through two major catabolic routes: lateral and angular dioxygenation pathways. This review considers previous decades and recent developments in bacterial diversity and aerobic bacterial transformation, degradation, and bioremediation of dioxins in contaminated systems.
Dioxin Degradation and Metal Biovolatilization at a Former Wood Treating Site
Hardy, L. Dioxin 2017: August 20-25, Vancouver, Canada. 3 pp, 2017
A large-scale contamination assessment of a former wood treating site was completed in 2015 to delineate the extent of contamination with dioxins, chlorophenols, hydrocarbons and metals. Results were compared to data collected in the 1990s to assess the extent of biodegradation.
Microbial Dechlorination of Polychlorinated Biphenyls, Dibenzo-P-Dioxins, and -Furans at the Portland Harbor Superfund Site, Oregon, USA
Environmental Science & Technology, Vol 49 No 12, 7227-7235, 2015
Rodenburg, L.A., V. Krumins, and J.C. Curran.
Concentrations of PCBs and PCDD/Fs in sediment and water collected during the site's remedial investigation were examined using positive matrix factorization to look for evidence that PCBs and PCDD/Fs are dechlorinated by anaerobic bacteria.
Biodegradation of PCDDs/PCDFs and PCBs
Urbaniak, M.
Biodegradation: Engineering and Technology, R. Chamy and F. Rosenkranz (eds). Intech Open Science, ISBN: 978- 953-51-1153-5, Chapter 4:73-100(2013)
This review examines the physical and chemical properties of dioxins and PCBs and how they can be broken down in the environment. Microbiological transformations discussed under aerobic, anaerobic, and sequential anaerobic-aerobic conditions. Physical transformations include photochemical and thermal degradation.
Quantifying Enhanced Microbial Dehalogenation Impacting the Fate and Transport of Organohalide Mixtures in Contaminated Sediments
Haggblom, M., D. Fennell, L. Rodenburg, L. Kerkhof, and K. Sowers. SERDP Project ER-1492, 221 pp, 2012
The project investigated techniques and amendments to enhance microbial dehalogenation in sediments contaminated with organohalide mixtures and developed methods and tools to monitor the effectiveness of biostimulation processes.
Capping/Containment
NAVFAC Technology Transfer Review: Sediment Reactive Capping
Naval Facilities Engineering Command, 11 pp, 2015
This fact sheet provides an overview of reactive capping as an emerging contaminated sediment remediation approach, with attention to capping approaches, materials, deployment, monitoring, and case study examples.
Field Experiment on Thin-Layer Capping in Ormefjorden and Eidangerfjorden, Telemark: Functional Response and Bioavailability of Dioxins, 2009-2011
Schaanning, M.T. and I. Allan.
Norwegian Institute for Water Research, REPORT SNO 6285-2012, 92 pp, 2012
A large-scale field study of in situ thin-layer capping was carried out at four sites in the dioxins-contaminated Grenlandfjord, Norway, to test and compare the effectiveness of active caps (2.5 cm thickness) consisting of powdered activated carbon (AC) mixed into clean clay, and nonactive caps (5 cm thickness) of clay without AC and of crushed limestone.
Chemical Methods
Potential Applicability of Assembled Chemical Weapons Assessment Technologies to RCRA Waste Streams and Contaminated Media
U.S. EPA, Technology Innovation Office. EPA 542-R-00-004. 88 pp, 2000.
Report examines seven ex situ technologies, including Commodore Advanced Sciences' Solvated Electron Technology and ELI Eco Logic's Gas Phase Chemical Reduction Technology.
Physical Methods
Technology Performance Review: Selecting and Using Solidification/Stabilization Treatment for Site Remediation
U.S. EPA, National Risk Management Research Laboratory, Cincinnati, OH. EPA 600-R-09-148, 28 pp, 2009
This technology performance review addresses important factors to consider in the selection of S/S treatment and discusses its implementation at seven sites.
Thermal Methods
Treatment by Thermal Desorption of Dioxin-Contaminated Soils and Vapor at Bien Hoa Airbase, Vietnam
Haemers, J., A. Vandekerckhove, and M. Stumbaugh
AEHS Foundation 32nd Annual International Conference on Soil, Water, Energy and Air, 20-23 March, San Diego, CA, 43 slides, 2023
A pilot study is being conducted to demonstrate the effectiveness of the Smart Burners treatment technology and design to meet site-specific target levels for dioxins and furans at the Bien Hoa Airbase, where thousands of barrels of Agent Orange were stored. Although the project started in early 2020, it was interrupted due to the COVID pandemic and resumed in December 2021. The pilot was restarted in February 2022 to treat the most contaminated materials in the area. After 40 days of treatment, the target temperature of 335°C was reached in the thermal pile and the temperature was maintained for at least five days. The presentation covers the treatment system design, operation, challenges, and results.
Performance Evaluation of USAID'S Environmental Remediation at Danang Airport
U.S. Agency for International Development (USAID), Office of Economic Growth, Education and Environment (E3), Office of Economic Policy, 110 pp, 2018
Remediation of the Danang Airport was a 10-year, $103.5 million project to characterize, remove and contain dioxin-contaminated soil and sediment from site hot spots. Originally, 73,000 m3 of contaminated soils and sediments were scheduled to be excavated from the airport into a secure landfill. Based on a 2010 environmental assessment, the project expanded to include in-pile thermal desorption to heat dioxin-contaminated soil to 335°C.
See video for more information.
Thermal Desorption Treatment of Dioxin-Contaminated Soil at the Former Allied Feeds Site, Sydney, Australia
Environmental Engineering Science. Volume: 27 Issue 7: July 14, 2010
William Troxler, John Hunt, Justin Taylor, and Campbell McNiven
About 175,000 tonnes of dioxin-contaminated soil at the Allied Feeds site have been treated using a directly heated thermal desorption plant. It is the first large-scale thermal remediation project conducted in Australia. The feed material contains high concentrations of dioxins/furans and potential dioxin/furan precursor compounds (e.g., chlorophenols and chlorobenzenes) and a high proportion of fine-grained spent lime with a high moisture content.
Sepradyne/Raduce High Vacuum Thermal Process for Destruction of Dioxins in INEEL/WERF Fly Ash
J.W. Adams, P.D. Kalb, and D.B. Malkmus. Brookhaven National Lab., BNL-52631, 16 pp, 1999.
An indirectly heated, high temperature (900°C), high vacuum (28 inch Hg) rotary kiln developed and patented to treat a dioxin-contaminated mixed-waste incinerator ash to decompose dioxins and furans at both low (450°C) and high (700-800°C) temperature regimes.
Full-Scale Incineration System Demonstration at the Naval Battalion Construction Center, Gulfport, Mississippi
Air Force Engineering and Services Center, ESL-TR-89-39, 1991
Cook, J.A., D.J. Haley, et al.
The overall goal of the project was to determine the cost and effectiveness of a 100 ton/day rotary kiln incinerator in processing soil contaminated with dioxins and other hazardous constituents of Herbicide Orange.
Federal Remediation Technology Roundtable Technology Cost and Performance Reports
- Glass Furnace Technology (GFT) Demonstration at the Hazen Research Center in Golden, Colorado and the Minergy GlassPack Test Center in Winneconne, Wisconsin (2004)
- In Situ Vitrification at the Parsons Chemical/ETM Enterprises Superfund Site, Grand Ledge, Michigan (1997)
- In Situ Vitrification, U.S. Department of Energy, Hanford Site, Richland, Washington; Oak Ridge National Laboratory WAG 7; and Various Commercial Sites (1997)
- Incineration at the Baird and McGuire Superfund Site, Holbrook, Massachusetts (1998) Incineration at the Times Beach Superfund Site, Times Beach, Missouri (1998)
- Incineration at the Vertac Chemical Corporation Superfund Site, Jacksonville, Arkansas (1998)
Research
Bioremediation
2,3,7,8-Tetrachlorodibenzo-p-dioxin Dechlorination Is Differentially Enhanced by Dichlorobenzene Amendment in Passaic River, NJ Sediments
Dean, R.K., C.R. Schneider, H.S. Almnehlawi, K.S. Dawson, and D.E. Fennell.
Environmental Science & Technology [Accepted for publication May 20, 2020]
DOI: 10.1021/acs.est.0c00876
The ability of native organohalide respiring bacteria to dechlorinate PCDDs was explored by first enriching bacteria from sediments of the Passaic River on TCE and 1,2-DCB. The enriched sediment cultures and original, unamended sediment were used as inoculum in a secondary experiment with 2,3,7,8-TeCDD, 1,2,3,4-TeCDD, and 2,7-DiCDD as target organohalides.
Identification of a Chlorodibenzo-p-dioxin Dechlorinating Dehalococcoides mccartyi by Stable Isotope Probing
Dam, H.T., W. Sun, L. McGuinness, L.J. Kerkhof, and M.M. Haeggblom.
Environmental Science & Technology, 53(24):14409-14419(2019)
DOI: 10.1021/acs.est.9b05395
While highly chlorinated dibenzo-p-dioxins are persistent under oxic conditions in anoxic environments, these organohalogens can be reductively dechlorinated to less chlorinated compounds that are then more amenable to subsequent aerobic degradation This study demonstrated the use of a DNA-stable isotope probing (SIP) approach to identify the bacteria active in dechlorination of PCDDs in river sediments, with 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TeCDD) as a model. In addition, pyrosequencing of reverse-transcribed 16S rRNA of TeCDD dechlorinating enrichment cultures was used to reveal active members of the bacterial community.
Genetic Bioaugmentation of Activated Sludge with Dioxin-Catabolic Plasmids Harbored by Rhodococcus sp. Strain
Environmental Science & Technology, 52(9):5339-5348(2018)
DOI: 10.1021/acs.est.7b04633
Chongyang R., Y. Wang, L. Tian, M. Chen, J. Sun, and L. Li.
This study examined the effectiveness of genetic bioaugmentation with dioxin-catabolic plasmids harbored by Rhodococcus sp. strain p52 in laboratory-scale, sequencing batch reactors.
Conjugative Transfer of Dioxin-Catabolic Megaplasmids and Bioaugmentation Prospects of a Rhodococcus sp.
Environmental Science & Technology, 51(11):6298-6307(2017)
DOI: 10.1021/acs.est.7b00188
J. Sun, Y. Qiu, P. Ding, P. Peng, H. Yang, and L. Li.
Joint Study of Bioremediation at Pilot Scale for Detoxification of Herbicide/Dioxin in Da Nang Hot Spot, Vietnam
Dang, T.C.H., H. Allen, B.H. Nguyen, V. Fong, T.H. Dam, N.Q. Nguyen, Q.H. Nguyen, K.H.C. Phung, T.N.A. Dao.
Organohalogen Compounds 72:1775-1778(2010)
The first joint study by Vietnamese and American researchers was conducted to demonstrate whether the soil at Da Nang can be bioremediated effectively using aerobic or anaerobic microbial processes. The study also sought to provide engineering design guidance to support the selection of either an aerobic or an anaerobic amendment recipe and an operating strategy to optimize biological treatment.
Development of Bioreactor System for Treatment of Dioxin-Contaminated Soil Using Pseudallescheria boydii
Ishii, K. and T. Furuichi.
Journal of Hazardous Materials 148(3):693-700(2007)
A conceptual feasible design of bioreactor system for treatment of dioxin-contaminated soils was developed that uses the dioxin-degrading fungus Pseudallescheria boydii (P. boydii). The dioxin-degradation conditions in bioreactor treatment were established by clarifying the inhibiting factors for the growth of P. boydii using both real contaminated and laboratory-prepared soils mixed with fly ash. In addition, an ethanol extraction process as post-treatment for the remaining dioxins, and the sterilization conditions of P. boydii, a weakly pathogenic fungus, in the residue was investigated.
In Situ Enhancement of Anaerobic Microbial Dechlorination of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans in Marine and Estuarine Sediments
SERDP Project CU-1208.
Haggblom, M.M., D. E. Fennell, and L.J. Kerkhof. (2006)
The objectives of this project were to identify environmental conditions and amendments that enhance and accelerate dechlorination of PCDD/Fs by indigenous microbial populations and to identify the organisms responsible for dechlorination using biomolecular methods.
Phytoremediation
Aided Phytoremediation to Clean Up Dioxins/Furans-Aged Contaminated Soil: Correlation between Microbial Communities and Pollutant Dissipation
Microorganisms 7(11):523(2019)
Meglouli, H., J. Fontaine, A. Verdin, M. Magnin-Robert, B. Tisserant, M. Hijri, and A. Lounes-Hadj Sahraoui.
Phytoremediation of aged dioxins/furans-contaminated soil was carried out through microcosm experiments vegetated with alfalfa combined with different amendments: an arbuscular mycorrhizal fungal inoculum (Funneliformis mosseae), a biosurfactant (rhamnolipids), a dioxins/furans degrading-bacterium (Sphingomonas wittichii RW1), and native microbiota.
Potential for Phytoremediation of PCDD/PCDF-Contaminated Sludge and Sediments Using Cucurbitaceae Plants: A Pilot Study
Bulletin of Environmental Contamination and Toxicology 97:401-406(2016)
Urbaniak, M., A. Wyrwicka, M. Zielinski, and J. Mankiewicz-Boczek.
Researchers evaluated the impact of sewage sludge and urban reservoir sediment on changes in total and Toxic Equivalency (TEQ) PCDD/PCDF concentration in soil and phytotoxicity using three test species — Lepidium sativum, Sinapis alba, and Sorghum saccharatum — during 5 weeks of Cucurbita pepo L. (zucchini) cultivation.
Methods for Treating Soils Contaminated with Polychlorinated Dibenzo-p-Dioxins, Dibenzofurans, and Other Polychlorinated Aromatic Compounds
Ambio 36(6):467-474(2007)
P. Haglund
This review provides a summary of methods for treating soils contaminated with polychlorinated aromatic compounds, especially polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs).
Photodegradation
Photodegradation of Dioxin in Contaminated Soil in the Presence of Solvents and Nanoscale TiO2 Particles
Environmental Technology 35(9-12):1121-1132(2014) [Abstract]
Binh, N.D., N.T.K. Oanh, and P. Parkpian.
Decomposition of 2,3,7,8-TCDD present in soil under UV illumination (350-400 nm) was investigated using a combination of nontoxic solvents mixed in soil and nanoscale anatase TiO2 (nTiO2) distributed on 2 mm topsoil surface. Three types of UV-exposure experiments were conducted: intermittent exposure (8 h/day) for 90 days and 120 days, sequential intermittent (120 days) and continuous (24 h/day) for the next 55 days, and continuous exposure for 55 days.
Physical Methods
Activated Carbon Could Stop Dioxin Health Risk
Environmental News Network, October 10, 2017
Article documents research that suggests activated carbon can help eliminate the health risks associated with soils, sediments and surface water polluted by dioxins. A series of three experiments were conducted to determine whether activated carbon effectively reduced the entry of dioxin into the food chain. The most toxic form of dioxin (tetrachlorodibenzo para dioxin) was mixed with silica, bentonite and activated carbon, exposing mice to each of the mixtures.