Title

Open Limestone Channels For Acid Mine Drainage Treatment: Performance and Design Guidance

Start Date

21-11-2014 8:00 PM

End Date

21-11-2014 10:00 PM

Description

The Swank open limestone channel has been treating Al-dominated acid mine drainage in the upper reaches of the Clearfield Creek watershed. The channel has been functioning since 2011 and is located in the village of Frugality. This channel is used to counter the effect of ac id mine drainage that averages an acidity of 83 mg/L CaCO3 and Fe, Mn and Al concentrations of 0.6, 0.9, and 9.2 mg/L respectively. The channel is 275 m long with slope of 6 to 9%. Treatment performance has been monitored over the life of the channel. In addition, rhodamine tracer tests were used to develop a reliable relationship between flow rate and residence time. As expected, increased residence time led to increased pH. However, the pH levels off at approximately 40 min of residence time once it reaches pH of around 4.4 due to the release of hydrogen ions from the formation of Al(OH)3. Acidity removal is directly proportional to residence time; the higher the residence time is the more acidity is removed. Using this information, a simple model has been created to predict treatment performance of this channel in order to guide the design of future channels treating similar waters.

Type

Poster

Session

Poster Presentations

Language

eng

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Nov 21st, 8:00 PM Nov 21st, 10:00 PM

Open Limestone Channels For Acid Mine Drainage Treatment: Performance and Design Guidance

Elaine Langone Center, Terrace Room

The Swank open limestone channel has been treating Al-dominated acid mine drainage in the upper reaches of the Clearfield Creek watershed. The channel has been functioning since 2011 and is located in the village of Frugality. This channel is used to counter the effect of ac id mine drainage that averages an acidity of 83 mg/L CaCO3 and Fe, Mn and Al concentrations of 0.6, 0.9, and 9.2 mg/L respectively. The channel is 275 m long with slope of 6 to 9%. Treatment performance has been monitored over the life of the channel. In addition, rhodamine tracer tests were used to develop a reliable relationship between flow rate and residence time. As expected, increased residence time led to increased pH. However, the pH levels off at approximately 40 min of residence time once it reaches pH of around 4.4 due to the release of hydrogen ions from the formation of Al(OH)3. Acidity removal is directly proportional to residence time; the higher the residence time is the more acidity is removed. Using this information, a simple model has been created to predict treatment performance of this channel in order to guide the design of future channels treating similar waters.