1. ENVIRONMENTAL MICROBIOLOGY
CHAPTER 25
Copyright © 2012 John Wiley & Sons, Inc. All rights reserved.

2. Energy Flow Producers Consumers Decomposers
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3. Biogeochemical Cycles – Water
Precipitation/ Evaporation
Transpiration
Respiration
Perspiration
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4. Biogeochemical Cycles – Carbon
Respiration
Combustion
Deposits in rocks and reefs dissolve
Photosynthesis
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5. Biogeochemical Cycles – Nitrogen
Denitrification by microbes
Microbial nitrogen fixation
Industrial and natural fixation
Animal wastes
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6. Nitrogen fixing Bacteria
Nitrifying Soil Bacteria
N2 to NH3
Cyanobacteria
Use H atoms from H2S
Methylotrophic bacteria
Fix in presence of methane, methanol
Rhizobium – symbiotic
Lives in legume root nodules
Root secretions enhance nitrogen fixation
© 2012 John Wiley & Sons, Inc. All rights reserved.

7. Water Pathogens and Purification
Chemical
Industrial, mining wastes
Biological
Sewage, manures
Pathogens may (or not) be present
Eutrophication is constant consideration
Indicator organism – E. coli
A fecal coliform
© 2012 John Wiley & Sons, Inc. All rights reserved.

8. Water Purity Tests Membrane Test Water is filtered
Membrane filter is placed on agar
Colonies are counted
MUG (ONPG) Test
Fluorescence (yellow color) indicates E. coli presence
© 2012 John Wiley & Sons, Inc. All rights reserved.

9. Sewage Treatment Sewage – used water Toilet Sinks, shower Industrial
Natural
Primary Treatment
Solids separated from liquid
Floating garbage is shredded
Skimmers remove oils and grease
Sands, gravels recovered
Organic solids (sludge) removed
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10. Secondary Sewage Treatment
Trickling filtration
Sewage aerated by spraying
Moves over a layer of aerobic microbes on rocks
80% removal of organic matter (BOD)
Activated sludge treatment
Air is pumped into liquid in a tank
Microbes are added as a sludge and decompose organic material
More efficient (90-95% BOD), also more costly
© 2012 John Wiley & Sons, Inc. All rights reserved.

11. Tertiary Treatment Filters can remove the last 5-20% of organics
Costly process
Applications: Cruise ships, sensitive environments
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12. Sewage Sludge Treatment
Solid Waste
Anaerobic microbes
Methane generation
Fuel source
Septic tanks
Aerobic degradation in leach field
Anaerobic in septic sludge
Cultures must be maintained, no harsh chemicals
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13. Bioremediation Applications Oil spills Dry Cleaning fluids Creosote
Microbes
Arthrobacter
White rot fungus
© 2012 John Wiley & Sons, Inc. All rights reserved.