Microbiological and Geochemical Dynamics of the Subsurface: - - PowerPoint PPT Presentation

Microbiological and Geochemical Dynamics of the Subsurface: chemical oxidation and bioremediation

• f organic contaminants

Nora Barbour Sutton

Soil Contamination

Sources of Contamination

 Gas Stations  Dry Cleaners  Industrial Factories  Transport Infrastructure

Types of Contamination

 Benzene, diesel, gas  Solvents: PCE  Heavy Metals

Groundwater Groundwater

Pure Pollutant Pure Pollutant

 PHYSICAL Remediation

 Physically remove contaminant from the

subsurface

 CHEMICAL Remediation (chemical oxidation)

 Contaminants are chemically degraded

 BIOLOGICAL Remediation (Bioremediation)

 Microorganisms degrade contaminants through

biological processes Transfer of contaminant to second location Conversion of contaminant into harmless products

Soil Remediation

Conversion: In situ chemical oxidation (ISCO) In situ bioremediation (ISB)

Benzene + oxidant → CO2 + H2O

Benzene + bacteria + O2 → CO2 + H2O + biomass

CHEMICAL Remediation BIOLOGICAL Remediation (Bioremediation)

Conversion: In situ chemical oxidation (ISCO) In situ bioremediation (ISB)

Groundwater

Oxidants Fenton’s Reagent H2O2 + Fe2+ Persulfate: S2O8

2-

Ozone O3 Permanganate MnO4

• Chemical oxidation followed by bioremediation

Amendments Nutrients Oxygen Carbon Source Bacteria

Conversion: In situ chemical oxidation (ISCO) In situ bioremediation (ISB)

Groundwater

Chemical oxidation + bioremediation

Parameter Chemical Oxidation (ISCO) Bioremediation (ISB) Time Rapid Slow Cost High Low Pure Pollutant Yes No Thorough No Yes Sustainable No Yes

 Technological Motivation

• Reduces toxicity
• Improves biodegradability
• Improves bioavailability
• Increases temperature and

mixing

• Oxidizing conditions
• pH change
• Soil organic matter

degradation

Oxidants Optimal pH Oxidation Potential (V) Fenton’s Reagent H2O2 + Fe2+ 3-4 2.8 (OH-·) Persulfate: S2O8

2-

3-4 to >10.5 2.6 (SO4

• ·)

Ozone O3 neutral 2.1 Permanganate MnO4

• neutral

1.7

Chemical oxidation + bioremediation

 Scientific Reasoning  Scientific Challenge

Chemical oxidation + bioremediation

 Scientifically Attractive: unique system to investigate

→ Fundamental Understanding of Entire System

• Groundwater
• Soil
• Contaminant
• Microbial Community

Groundwater

Part One: Review; limitations to ISB Part Two: Aerobic ISB: TPH

Diesel bioremediation with oxygen

Part Three: Anaerobic ISB: chlorinated ethenes

PCE and TCE bioremediation with electron donor

Chemical Oxidation and Bioremediation Motivation

Dissertation Structure

Part One: Review; limitations to ISB Part Two: Aerobic ISB: TPH Part Three: Anaerobic ISB: chlorinated ethenes

Chemical Oxidation and Bioremediation

Literature Laboratory Field

Motivation

Dissertation Structure

Part One: Review; limitations to ISB Chapter 2 Review of ISCO coupled with ISB Chapter 3 Bioavailability limitations to bioremediation Chapter 4 Field limitations to bioavailability Part Two: Aerobic ISB: TPH Chapter 5 Aqueous constituents impact bioremediation Chapter 6 Microbial community dynamics following

• xidation

Chapter 7 Geochemical and microbial community changes during ISCO and ISB Part Three: Anaerobic ISB: chlorinated ethenes Chapter 8 Development of OHRB resilience to chemical

• xidation

Chapter 9 Changes to OHRB and rdh abundance during ISCO

Chemical Oxidation and Bioremediation

Literature Laboratory Field

Motivation

Dissertation Structure

Dissertation Toolbox

Aspects Chapter 3 4 5 6 7 8 9 soil type X X X chemical oxidant type X nutrient amendment X X microbial community X X X X X X groundwater X X X X soil characteristics X contaminant characteristics X X X

System Microbiological Geochemical

Major Conclusions

 Technological:

 Chemical oxidation plus bioremediation is very effective

Major Conclusions

 Technological:

 Chemical oxidation plus bioremediation is very effective

 Scientific:

 Bacteria are very resilient

Major Conclusions

 Technological:

 Chemical oxidation plus bioremediation is very effective

Scientific:

 Bacteria are very resilient  Chemical oxidation impacts subsurface processes

Major Conclusions

Technological:

Chemical oxidation plus bioremediation is very effective

Scientific:

 Bacteria are very resilient  Chemical oxidation impacts subsurface processes  DNA-based tools are essential to understanding system

Major Conclusions

Technological:

Chemical oxidation plus bioremediation is very effective

Scientific:

 Bacteria are very resilient  Chemical oxidation impacts subsurface processes  DNA-based tools are essential to understanding system

→ Fundamental Understanding of Entire System

Program

 Defense:

 13:30-13:45 Presentation  13:45-14:30 Examination by Committee  14:30-14:45 Committee withdraws  14:45-15:00 Announcement of decision

 Reception:

 15:00-15:45 in Aula

 Dinner and Party:

 17:30 Cafe Carre, Vijzelstraat 2

Microbiological and Geochemical Dynamics of the Subsurface: chemical oxidation and bioremediation

• f organic contaminants

Nora Barbour Sutton