Enhanced Bioremediation Papers
This Website is being launched to showcase a specific paper, entitled, "Feasibility of Bioremediation of Agent Orange/Dioxin in Vietnam."
This Website is being launched to highlight a specific paper, entitled, "Feasibility of Bioremediation of Agent Orange/Dioxin in Vietnam." The continued contamination of soil and sediment by wartime defoliants applied in third world countries is unacceptable. It is appropriate that the West mitigate the toxic and environmental consequences of its actions. The cost of detoxifying vast amounts of contaminated soil and sediment using traditional, robust technologies is beyond the means of the these countries. In Da Nang, for example, in 2009 a contractor estimated it would cost about $13.8 M for thermal treatment of the 26,814 cubic meters of contaminated soil identified in the extent of contamination studies at a unit cost of $515/cu.m. The original estimate of 45,000 cu.m. by the Ministry of Defense was based on a fixed excavation depth. Researchers showed this volume could be reduced by use of an empirically derived depth attenuation factor (d1/2=0.17m), which would limit excavation to the contaminated soil only. The actual cost of thermal treatment over 10 years was $127 M, and it included treatment of an additional 18,000 cu. m. from the MOD estimate plus an additional 50,000 cu. m. of "moderately contaminated" soil at a unit cost of $1,337/cu.m. The cost of only the thermal treatment portion was $48.7 M ($513/cu.m.), which is close to the original unit cost estimate. This closeness of the unit costs might be the result of the economy of scale due to treatment of 68,000 cu.m. of soil which already may have been below the cleanup goal, and could have been considered uncontaminated.
Biological treatment, which is much more energy efficient (i.e., less robust), is proven by this research to achieve regulatory goals. It was estimated to cost only about $2.7 M in 2009 ($100/cu.m.) for the 26,814 cu.m., or $4.7 M for the 47,300 cu.m.; the maximum estimate for biological treatment using an active landfill including non-treatment costs was about $7.1 M. This study showed that the cleanup goal could easily have been reached in less than one year. As demonstrated by the management of the pilot study, with safety training, local labor and materials could be used to conduct the treatment operation with a minimum of outside funding.
The enormous savings of using biological treatment would free up major resources better spent on needed improvements in health care for the long term effects of chlorodibenzodioxins rather than on soil remediation.
Other research has provided anecdotal evidence of dioxin biodegradation, but the data from these studies often is limited due to the high cost of chemical analysis, and the variance of the data is high due to inherent variations in soil sampling and extraction methods. One data point using 3 replicates cost about $1,000 for the Da Nang study. This limitation adds a layer of complexity to interpreting anecdotal results, which may rely on lower quality analytical results. The current research presents statistically reliable evidence that bioremediation will work for Agent Orange and dioxin residues. In fact, once their relationship is established, it may be feasible to analyze for Agent Orange herbicides rather than dioxin as an operational measure of progress, which would reduce analytical costs dramatically. It may be too late to affect remedy selection for Da Nang, but remediation is still needed at 2 other former air bases and an estimated 26 smaller sites.
Bioremediation also provides significant savings in greenhouse gas emission during treatment over thermal treatment, because the treatment focuses on mineralization of specific pollutants, rather than on burning the organic carbon bound tightly to the native soil. In fact, the microbial degradation process sequesters much of the available carbon into cell mass, which is then bound in the soil for a long time.
Publication of this research is expected to lead to more development, through field application, of a cost-effective solution to a serious environmental problem..
Fullscale Removal of PCP from Pringle Post and Pole Site - Resuts of Bioremediation Cleanup in Pringle, South Dakota
Performance and Process Economics of Anaerobic Bioremediation of Toxaphene - Results of Bioremediation of Two Aerial Pesticide Sprayer Sites in Arizona
Rapid Removal of Toxaphene Using Anaerobic Bioremediation Technology - Results of Toxaphene Bioremediation Projects in New Mexico
Fullscale Removal of PCP from Granite Timber Post and Pole Soil - Results of PCP Bioremediation at Granite Timber near Philipsburg, Montana