groundwater current events - michigan water environment ... - groundwater.pdf · groundwater...
TRANSCRIPT
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Groundwater Current
Events
New policies- New problems- New criteria
Three main topics
� New policy- Electronic reporting
� New Problem- What’s with the focus on BOD?
� New Criteria- Michigan Criteria For Subsurface Disposal
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Electronic Reporting
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Write down this address� https://secure1-qz.state.mi.us/e2rs/
� Or www.michigan.gov/deq and click on online services
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Why are they asking for BOD? � The mystery of the red slime
Presentation of evidence (I)�The story of a food processor
� sugar water
� Odor complaints
� COD measured in monitor wells
� Ponding and pooling in fields
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Presentation of evidence (I)�The story of a food processor
� sugar water
� Odor complaints
� COD measured in monitor wells
� Ponding and pooling in fields
� Slimy red water and rust
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Remember redox reactions?� Iron + water + air = rust
� Fe + H2O + O2 = FeO3 + 2H
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Presentation of evidence (II)�The story of a food processor
� sugar water
� Odor complaints
� COD measured in monitor wells
� Ponding and pooling in fields
� Slimy red water and rust
- BOD
- BOD
- BOD
Anaerobic conditions
Focus on BOD � Anaerobic conditions in surface water?
� For a groundwater discharge- What happens if oxygen depleted in soil?
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Aerated soil particle
Fe3+
(Ferric oxide or
Iron sulfide)
Mn4+
(Manganese dioxide)
As
N
O2
O2
CO2
CO2N
O2
Soil with BODFe3+
Mn4+
Al
As
O2
CO2
O2
BOD critter
O2
O2
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Soil with BOD-anoxic condition
Fe3+
Mn4+
Al
As CO2
???
A friendly chemical equilibrium reaction for you!
� 2FeS2 + 7O2 + 2H2O (insoluble iron pyrite)
� 2Fe 2+ + 4SO42- + 4H+ (soluble iron sulfate)
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Soil with BOD- using O2 from minerals
2 Fe 2+ + (4SO42-) + 4H
(soluble iron sulfate)
Mn4+
Al
As CO2
O2
(4SO42-)
Presentation of evidence (III)�The story of a food processor
� sugar water
� Odor complaints
� COD measured in monitor wells
� Ponding and pooling in fields
� Slimy red water
- BOD
- BOD
- BOD
Anaerobic conditions
Soluble iron and other metals
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How to respond to the problem?� BOD concentration
� Land area
� Permeability
� Ideal BOD loading rate?? (not really known)
50 lbs BOD per acre per day
Current events #3� Rewrite of the Michigan Criteria
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Michigan Criteria Update� Used for sewage flow up to 20,000 GPD
� Recall flows >6,000 GPD needs
authorization
� Range of suitable soils expanded
� No perc testing. Use table values for hydraulic loading
� Gravity distribution only acceptable in systems < 1,000 GPD
� Major changes in basis of design for flow
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Michigan Criteria Update� Changes required depth to groundwater (3 ft.
to groundwater instead of 4 ft.) Also allows for “alternative treatment”
� 18 inches of undisturbed soil to high groundwater
� Simple septic/tile field not allowed for >6,000 GPD flows
� Wastewater strength assessment required.
� Process for determining aquifer vulnerability.
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Questions?