Bioremediation of a Hazardous Pollutant

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Bioremediation of a Hazardous Pollutant

• Kevin Drees
• IOFT 1101
• October 15-18, 2007

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What are hazardous pollutants?

• Misplaced chemicals that cause a harmful effect
  in the environment
• Types of harmful effects
• Toxic (poisonous)
• Carcinogenic
• Mutagenic
• Teratogenic (birth defects)
• Flammable
• Corrosive
• Explosive
• Endocrine Disruptive

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Common Pollutants

• Petrochemicals
• Hydrocarbons (only carbon and hydrogen)
• Mostly alkanes
• Oil spills
• Leaky underground storage tanks
• Coal tar

CH3 (CH2)n CH3
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Common Pollutants

• PCE (perchloroethylene),
• TCE (trichloroethylene)
• Common drycleaning chemical
• Most common groundwater pollutant
• Used to clean circuit boards and degrease engine
  parts
• Common pollutant at electronics factories,
  airports, and military facilities

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Common Pollutants

• Heavy metals
• Mercury, Lead, Cadmium, Chromium, Zinc
• Mine tailings
• Burning coal (Mercury)
• Burning leaded gasoline
• Old paint (Lead)

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Common Pollutants

• Polychlorinated Biphenyls (PCBs)
• Transformer fluid
• Capacitor manufacture
• Pulp bleaching
• Bioaccumulates!

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Where is the pollution?

• Groundwater aquifers
• Soil
• Surface waters and sediment
• Air

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How do we clean up pollution?

• Remediation
• Ex-situ (off-site) strategies
• Excavation/pumping, followed by
• Landfill
• Incineration
• Chemical removal
• In-situ (on-site) strategies
• Immobilization (chemicals, wells, membranes)

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Problems with traditional remediation

• Expensive!!!
• Invasive
• Residual contamination
• Landfilling not a permanent solution, just a
  delay tactic

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Bioremediation

• Bacteria eat or immobilize many types of
  pollutants
• Bioremediation using bacteria to degrade or
  immobilize pollutants
• Can be in-situ
• Inject nutrients organisms need to degrade
  pollutant into contaminated area
• Can be ex-situ
• Excavate soil, pump water into bioreactor
• Can use indigenous microbes, or introduce them

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Advantages of Bioremediation

• Cheap
• Less invasive
• Long-term
• Can handle residual contamination

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How do bacteria degrade pollutants?

• All organisms need several things to live
• Chemical building blocks (containing C, N, P, O,
  S)
• Energy to power cell biochemical reactions
• Breaking chemical bonds in food
• Method of recycling energy-producing molecules
• Ex respiration (oxygen)
• Vitamins and minerals
• Active sites of enzymes
• Pollutants can serve as one or many of these
  requirements!

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Ex Petroleum Degradation

• Petroleum provides carbon building blocks for
  cells.
• In addition, cells require
• Nitrogen, phosphorous, and other nutrients
• Oxygen

CH3 (CH2)n CH3
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Todays Lab

• Create oil-contaminated microcosms
• Sand, water, and oil in a Petri dish
• Introduce petroleum-degrading bacterium
• Achromobacter sp. ATCC 21910
• Isolated from a crude oil-contaminated beach
• Introduce nutrients the bacteria need to degrade
  the oil
• Fertilizer (NH4NO3, K2HPO4)
• Carefully observe your microcosms, now and next
  week.
• Smell, appearance

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Experimental Setup
Dish Sand (30 gm) Oil (10 drops) Water Fertilizer (1 ml) Bacteria (1 ml)
1 X X 8 ml X X
2 X X 9 ml X
3 X X 9 ml X
4 X X 10 ml
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Procedure

• Label top and bottom of Petri dish with treatment
  number, lab group number, lab time.
• Weigh out 30 g sand into each dish
• Clean up any spilled sand!
• Add fertilizer, bacteria, oil at stations.
• Add water using graduated cylinder
• Stir sand well with glass rod.
• Clean glass rod with ethanol and a tissue between
  dishes!
• Make observations
• Leave completed microcosms on your bench. Your
  TA will put them in the 30C incubator

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Safety Issues

• Oil is toxic. Avoid contact.
• Achromobacter sp. ATCC 21910 is related to a
  pathogen.
• Wear labcoats, gloves, safety glasses.
• Avoid spilling/dripping bacterial culture
• Alert TA in the event of a spill, on the bench or
  your lab coat
• Wipe benches down, BEFORE AND AFTER, with
  disinfectant solution.
• Wash your hands!

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Questions?