Skip Navigation
Button that takes you to back to the home page. Button that takes you to the teacher pages. Button that takes you to the modules and activities page. Button that takes you to the related links page. Button that takes you to the references page. Button that takes you to the Problem Based Learning model page. Button that takes you to the glossary page.Image map of some Water Quality puzzle pieces.  Please have someone assist you with this.

Button that takes you to the Overview page.
Button that takes you to the Acid Mine Drainage page. Button that takes you to the AMD Chemistry page. Image that says AMD Remediation.
Button that takes you to the Agriculture page.
Button that takes you to the Sewage page.
Button that takes you to the Dredging page.

Water Pollution: Acid Mine Drainage: Remediation
Image of a mine drainage treatment facility.Remediation is the process by which something is corrected. The remediation of acid mine drainage (AMD) refers to the process by which heavy metals are removed from the AMD-polluted water before it is discharged into a stream. Treatment of AMD commonly consists of adding strong bases, such as caustic soda (NaOH, sodium hydroxide), soda ash (Na2CO3, sodium carbonate), or lime (CaO, calcium oxide; or Ca(OH)2, calcium dihydroxide) to the polluted water. The bases neutralize the acidity of the AMD. Because they are strong bases, they ionize and dissolve in water. The resulting hydroxide (OH-) and carbonate (CO32-) ions combine with hydrogen (H+) ions in the AMD, taking them out of solution. The products of this reaction are water (H+ + OH- H2O) and carbonic acid (H2CO3). Carbonic acid is relatively harmless because it is a weak acid. It can be dissociated as water and carbon dioxide, as described in the bicarbonate buffering system. Photo:Mine drainage treatment facility. Photo courtesy of Dr. Ben Stout.

Note the color change in the treatment pond pictured above. The water is red where mine effluent enters the pond. The red color is the iron hydroxide precipitating out of the water. Mechanical aeration (mixing the water) speeds the process by making more oxygen available. (See reactions 1 and 3 in "AMD Chemistry"). The iron hydroxide precipitate eventually settles to the bottom of the pond. This is the area where the red water turns green. The green color is a result of sulfate (SO42-), sodium (Na+), and calcium (Ca2+) ions remaining in the water after acid neutralization reactions occur.

 

Overview ..|.. Acid Mine Drainage ..|.. Agriculture ..|.. Sewage ..|.. Dredging
AMD Chemistry / AMD Remediation
Glossary  .|
Related Links  .|.. References ..|.. PBL Model  .|

  Home ..|.. Teacher Pages ..|.. Modules & Activities  

Button that takes you back to the Water Quality main page.

HTML code by Chris Kreger
Maintained by ETE Team
Last updated November 10, 2004

Some images © 2004 www.clipart.com

Privacy Statement and Copyright © 1997-2004 by Wheeling Jesuit University/NASA-supported Classroom of the Future. All rights reserved.

Center for Educational Technologies, Circuit Board/Apple graphic logo, and COTF Classroom of the Future logo are registered trademarks of Wheeling Jesuit University.