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  1. 1. Web-based Class Project on Geoenvironmental Remediation Report prepared as part of course CEE 549: Geoenvironmental Engineering Winter 2013 Semester Instructor: Professor Dimitrios Zekkos Department of Civil and Environmental Engineering University of Michigan BIOREMEDIATION Prepared by: Sophia Alliota Josh Colley With the Support of:
  2. 2. What is Bioremediation? • Bioremediation refers to a number of technologies that treat contaminated soil and groundwater by using microorganisms
  3. 3. Applicability • To contaminants: – Organic • Excellent for biodegrading organic contaminants e.g. petroleum hydrocarbons, chlorinated and non chlorinated compounds, wood treating agents – Inorganic • Metal sulphides such as those found in Acid Mine Drainage (AMD) can be treated easily using passive anaerobic wetlands • Heavy metals can also be immobilized
  4. 4. • To ground conditions: – Soil treatment • Almost all soils can be treated using bioremediation as long as the moisture content is adequate to support microorganisms • Low permeability soils can be hard to treat when trying to permeate amendments through the soil mass – Groundwater treatment • Soils of k=10-4 cm/s or greater are treatable • Again, soils with low k are hard to treat
  5. 5. Common Contaminants • Organic contaminants include: – Polycyclic Aromatic Hydrocarbons (PAHs) • E.g. benzene, toluene – Polychlorinated Biphenyls (PCBs) – Pesticides and herbicides – Chlorinated solvents • E.g. perchloroethene, trichloroethene • Inorganic: – Heavy metals – AMD effluent containing metal sulphides
  6. 6. Common Sources of Contamination • Underground Storage Tanks (USTs) – Leakage of fuels e.g. petroleum • Wood treating facilities – Preservatives such as creosote common • Arsenals • Chemical manufacturing plants
  7. 7. Theory • Fundamentally bioremediation uses microorganisms (e.g. bacteria, yeast and fungi) to break down harmful contaminants • This can be facilitated by using native indigenous microbes or by adding foreign exogenous ones to populate the soil • Different types of microorganisms function well in different conditions: – Oligotrophs function well in low carbon environments – Eutrophs function well in high carbon environments
  8. 8. (USEPA, 2012)
  9. 9. • Microorganisms can break down contaminants: – Under aerobic (oxygen present) conditions: – Under anaerobic (oxygen not present) conditions: • E.g. fermentation, denitrification • Sulfate reduction in anaerobic wetlands
  10. 10. • Conditions must be suitable to promote microbial activity – Temperature 15-45°C – pH ~7 – Moisture content 40-80% of field capacity – Oxygen >2mg/l (aerobic) or <2mg/l (anaerobic) – Nitrogen, Carbon, Phosphorous etc • Conditions can be improved be adding amendments – Oxygen Releasing Compounds, Nitrogen, Phosphorous
  11. 11. Flexible methods • Treatment methods can be: – In-situ (i.e. in the ground) • E.g. injection of amendments – Ex-situ (i.e. out of the ground) • E.g. composting, land farming – Aerobic or anaerobic Landfarming (ETec, 2013)
  12. 12. • An example of an in-situ aerobic method for treating soil and groundwater (USEPA, 2001)
  13. 13. Advantages • Organic contaminants can be broken down into other nontoxic chemicals • Minimal equipment requirements • Can be used in-situ or ex-situ • Can treat wide range of contaminants • Low cost – $30-750 per cubic yard of soil – $33-200 per 1000 gallons of water • Good public perception since ‘natural’ process
  14. 14. Disadvantages • Contaminants may only be partially broken down creating toxic by-products • Sensitive to ground conditions • Monitoring to accurately track degradation • In ex-situ processes VOCs need to be controlled
  15. 15. Field Setup: In-situ Bioremediation (Tlusty, 1999)
  16. 16. Field Setup: Ex-situ Bioremediation (USEPA, 1995a)
  17. 17. Field Setup: Land Farming (ETec, 2013)
  18. 18. Field Setup: Windrow (Proper, 2013)
  19. 19. Case Study: French Limited Superfund Site • French Limited in Crosby, Harris County, Texas (EPA Region 6) was a 25-acre sand mining site from 1950-1965 • The primary contaminants in this waste were benzo(a)pyrene, vinyl chloride, and benzene • In 1987, the EPA decided to try bioremediation, which was the first time that technology was used at a Superfund site
  20. 20. Case Study: French Limited Superfund Site (EPA, 1993)
  21. 21. Case Study: French Limited Superfund Site • Bioremediation was chosen because it offered a less expensive option to destroy the same amount of waste as an incinerator in the same amount of time • In-situ slurry-phase bioremediation was conducted to remedy the site
  22. 22. Case Study: French Limited Superfund Site (EPA, 1993)
  23. 23. Case Study: French Limited Superfund Site • Treatment process took 11 months to treat 300,000 tons of soil and sludge • Post-treatment benzene concentrations 7-43 mg/kg • After initial remediation, the French Limited site has been revisited several times to mitigate contamination from floods
  24. 24. References • ETec Environmental Technologies LLC (2013). "Landfarming". ETec LLC. (March 13th 2013) • Tlusty, B. (1999) "In Situ Bioremediation of Tricholoroethylene". Resoration and Reclamation Review, Student Online Journal - Department of Horticultural Science, University of Minnesota, Vol 5, Number 2, 1-8. • Proper (2013). "PROPER Gallery - Bioremediation Gallery". Proper. lery/biore%20galery.htm (March 13th 2013). • USEPA. (1993). "Superfund at Work: Hazardous Waste Cleanup Efforts Nationwide". USEPA. • USEPA. (2001a, September). "Use of Bioremediation at Superfund Sites". EPA 542-R-01-019 . • USEPA. (2012, September). "A Citizen's Guide to Bioremediation". EPA 542-F-12-003 .
  25. 25. More Information More detailed technical information on this project can be found at: projects/geoenvironmental-remediation-technologies

Editor's Notes

  • In-situ bioremediation requires biostimulation, enhancing soil with oxygen, moisture, and
    nutrients, for effective treatment. These constituents are added at injection points, as depicted
    in the figure.
  • In slurry phase bioremediation, contaminated soil is mixed with water to create slurry, and then aerated. The advantage of this type of bioremediation is that constituents such as pH, temperature, and nutrients are monitored and can be adjusted to aid treatment.
  • Land farming is a form of solid-phase bioremediation. The process involves spreading the contaminated soil in fields or treatment beds that are inch thick. The soil is then tilled to allow oxygen into the soil. Treatment is achieved through biodegradation, aeration, and photoxidation.
  • Windrow systems are a type of composting, another form of ex-situ solid phase bioremediation. Compost is stacked in elongated piles and aeration of the soil is accomplished by tearing down and then rebuilding the piles.