1 / 26

Bioremediation of Explosive Contaminants

Bioremediation of Explosive Contaminants. Matt Mahler. Introduction. In the late 19th century many nitramine compounds were created through the process of nitration. During WW I and WW II their application for industrial and military purposes was investigated.

jana
Download Presentation

Bioremediation of Explosive Contaminants

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Bioremediation of Explosive Contaminants Matt Mahler

  2. Introduction • In the late 19th century many nitramine compounds were created through the process of nitration. • During WW I and WW II their application for industrial and military purposes was investigated. • By 1945 an estimated 1.2 million tons of soil surrounding production plants had been contaminated. (Lewes et.al, 2004)

  3. Introduction Cont’d • Enter the environment through wastewater from production plants. • Many bioremediation techniques are currently being investigated. • Compounds Discussed: TNT, RDX, HMX and CL-20 (Lewes et.al, 2004)

  4. Bioremediation of RDX • Readily degradable in a variety of environments. • Aerobic and Anaerobic Mechanisms • Two-Electron Reductive Pathway and Denitration (Crocker et. al, 2006)

  5. RDX - Two Electron Reductive Pathway

  6. RDX - Two Electron Reductive Pathway Cont’d • Special Notes • Mechanism II: No Ring Cleavage • Mechanism III: Uses Oxireductase • Still Disagreement Among Researchers

  7. RDX - Denitration • Believed to be the most common method of RDX Degradation. • Occurs aerobically and anaerobically

  8. RDX - Denitration Cont’d

  9. RDX - Denitration Cont’d • Special Notes • Aerobic: • NDAB is Readily Degraded by Many Organisms • In the anaerobic denitration process two electrons are added prior to ring cleavage.

  10. Bioremediation of HMX • Most methods that degrade RDX have also been shown to degrade HMX. • Also involves aerobic and anaerobic processes.

  11. Bioremediation of HMX • Aerobic • Methylobacterium Cometabolize HMX with Carbon Dioxide • Anaerobic • Some process as RDX , however McCormick’s Pathway not aplicable.

  12. Bioremediation of CL-20 • Recently Developed Nitramine • 20% More Powerful Than HMX • Degradation Mechanisms Similar To Those of RDX and HMX.

  13. Bioremediation of CL-20 • Anaerobic Degradation • Cloistridium Utilizes CL-20 for Cell Growth • Catalyzed by Dehydrogenase • End Products: Acetic Acid, Glyoxal, Nitrous Oxide and Nitrogen Dioxide

  14. Bioremediation of CL-20 • Aerobic Degradation • While possible, CL-20 most occur in high concentrations for process to take place. • In environments that support fungal growth, white-rot fungi is responsible for aerbic mineralization of CL-20.

  15. Enhancing Anaerobic Nitramine Treatment • Anaerobic Treatment of HMX, RDX and TNT • Current Limiting Step in Process is the Availability of Substrate. • Historically Starch Has Been Used

  16. Enhancing Anaerobic Nitramine Treatment • Anaerobic Treatment of HMX, RDX and TNT • Recent Research Introduced Propylene Glycol and Ethanol to Cultures • Consumption of these Molecules Produces Hydrogen Gas

  17. Enhancing Anaerobic Nitramine Treatment

  18. Enhancing Anaerobic Nitramine Treatment • Conclusion • Addition of Propylene Glycol and Ethanol Did Increase Rate of Degradation • Not Necessary for TNT and RDX Degradation.

  19. Enhancing Nitramine Treatment • Enhancing Treatment CL-20 • Added Sucrose, Pyruvate, Yeast, Acetate, Glucose and Starch to act as Carbon Sources

  20. Enhancing Ntramine Treatment • Conclusions • The addition of these substrates does increase the rate of CL-20 Degradation. • Process is independent of microbial cell growth. • Over half randomly selected microbes could degrade CL-20.

  21. Aerobic Degradation of CL-20 • Researchers investigated the use of P. Chrysosporium for its use as a CL-20 degrading molecule. • At the end of the 8 day experiment concentrations of CL-20 were virtually non-existant. • Growth of fungi was observed.

  22. Case Study • Louisiana Army Ammunition Plant • Currently disposes of waste through dumping and incineration. • Experiment performed to analyze the potential use of land farming and soil slurry as potential methods of waste treatment

  23. Case Study • Results • Soil Slurry showed 99% removal of TNT and near complete removal of HMX and RDX at the end of the 182 day experiment • Land Farming showed 82% removal of TNT and little to know RDX and HMX removal after same amount of time.

  24. Conclusion • The production of nitramines is only expected to increase. • More efficient and economical degradation mechanisms must be found.

  25. Conclusion

  26. QUESTIONS?

More Related