Acid Mine Drainage (AMD)

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Acid Mine Drainage(AMD)
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Acid Mine Drainage

• Outflow of acidic water, usually from abandoned
  coal mines
• Old mine fills up with water
• Heavy metals get into the water (pyrite iron
  sulfide)
• Forms sulfuric acid and dissolved iron
• When water comes in contact with air it oxidizes
  the iron and turns orange

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AMD in Pa

• Pa has relatively high amounts of AMD b/c of the
  high number of coal mines
• Mostly in Western PA
• Also in West Virgina, Ohio, etc
• http//www.youtube.com/watch?vil0UOMa-WPA
• http//www.youtube.com/watch?vGR1saXGRezc

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Effects

• Lowers pH of the stream usually ph of 5 or
  below
• Effects growth / reproduction of aquatic plants
  and aquatic organism (like macroinvertebrates)
• Effects fish populations
• In drinking water can cause birth defects
• Effects recreation and tourism

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Treatments

• Active Treatment
• Add basic substances to the water to try to
  neutralize the acidity
• Passive Treatment
• Construct wetlands add neutralized water and
  allow heavy metals to precipitate out
• http//www.youtube.com/watch?v6ZHpPynNokM

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Causes

• AMD occurs when the pyrite iron sulfide from the
  coal becomes exposed and reacts with both the
  water from the stream and oxygen, causing
  dissolved iron and sulfuric acid to form.
• The rate and extent to which it forms varies
  depending on certain bacteria.

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Effects?

• The yellow/orange discoloration in the streams
  harms ecosystems because it smothers the animal
  and plant life and increases the pH levels.
• Because of the highly toxic levels of acidity,
  left over metals, and sediments all animal life
  in the streams die.

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AMD In Pennsylvania

• Because of all the abandoned coal mines, more
  than 3,000 miles of streams are contaminated in
  PA.
• It is the most extensive water pollution problem
  in the four major rivers in PA.
• PA loses 67 million a year in treatment of the
  contaminations.

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Active Treatment Pros Cons

• Pros
• Is a great to raise pH levels and reduce the
  presence of metals.

• Cons
• Lime, soda ash, and ammonia are very expensive to
  maintain
• Disposal of metal loaded waste can be a problem.

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Passive Treatment

• Passive treatment has been used since early
  1990s. It uses a variety of treatment to raise
  pH levels.

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Passive Treatment Pros Cons

• Pros
• It needs only periodic maintenance
• Lower costs than Active Treatment

• Cons
• not enough land