Web-based Class Projecton Geoenvironmental Remediation

Report prepared as part of course CEE 549: Geoenvironmental Engineering

Winter 2013 SemesterInstructor: Professor Dimitrios Zekkos

Department of Civil and Environmental Engineering University of Michigan

BIOREMEDIATIONPrepared by:

Sophia Alliota Josh ColleyWith the Support of:

What is Bioremediation?

• Bioremediation refers to a number of technologies that treat contaminated soil and groundwater by using microorganisms

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

• 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

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

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

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

(USEPA, 2012)

• 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

• 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

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)

• An example of an in-situ aerobic method for treating soil and groundwater

(USEPA, 2001)

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

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

Field Setup: In-situ Bioremediation

(Tlusty, 1999)

Field Setup: Ex-situ Bioremediation

(USEPA, 1995a)

Field Setup: Land Farming

(ETec, 2013)

Field Setup: Windrow

(Proper, 2013)

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

Case Study: French Limited Superfund Site

(EPA, 1993)

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

Case Study: French Limited Superfund Site

(EPA, 1993)

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

References• ETec Environmental Technologies LLC (2013). "Landfarming". ETec LLC.

http://www.etecllc.com/landfarming-bioremediation.asp (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. http://proper.menlh.go.id/proper%20baru/html/menu%205/proper%20galery/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 .

More InformationMore detailed technical information on this project can be found at:

http://www.geoengineer.org/education/web-based-class-projects/geoenvironmental-remediation-technologies