[permaculture] Gleying, bentonite

defrey at bioshelter.com defrey at bioshelter.com
Fri Jan 6 19:32:04 EST 2012


  I built a constructed wetland for grey water treatment at the 
Macoskey Center at Slippery Rock University in 2005 . We supplemented 
the site's existing clay with clay from a nearby gravel pit (we are in 
a glaciated region and the sand and gravel and clay is sometimes 
concentrated in large areas) and added bentonite clay to the top 
several inches. the first test only held water 12 of the 18 inches 
desired. So we added  a couple hundred pounds more bentonite to the top 
six inches of the 10 ft by 14 ft basins. this worked fine since 2005/

  We were trying to make a "geological" instead of a "technological" 
container so we used clays instead of a rubber or plastic type liner.  
Kept constantly wet, the bentonite is in theory self sealing, whereas a 
liner would need repaire or replaces with inevitably punctured by 
critters

  the system is detailed in my book Bioshelter Market Garden, A 
Permaculture Farm . 

  Darrell Frey




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