Natural silt fence

Abstract

A geotextile, and a silt fence made therefrom, comprised of a biodegradable nonwoven first sheet in combination with a woven biodegradable second sheet, stitched together by a natural, biodegradable thread. The silt fence includes stakes for installation at a work site. The stakes are typically biodegradable. Substantially the entire combination of elements is biodegradable at a typical work site.

1 . A geotextile which is biodegradable, resistant to ultraviolet degradation, and contains essentially no petroleum-based materials, comprising:
 a first sheet layer comprised of spunbond nonwoven natural fibers;   a second sheet layer comprised of natural fibers, the second sheet layer brought into adjacent alignment with the first sheet layer; and   natural fiber thread inserted through the aligned first and second sheet layers to maintain contact of the first sheet layer with the second sheet layer prior to biodegradation of the geotextile.   
     
     
         2 . The geotextile of  claim 1  further comprising posts attached to the geotextile to produce a silt fence, the posts with an extending portion for insertion into soil. 
     
     
         3 . The geotextile of  claim 1  wherein the spun bond nonwoven natural fibers are comprised of polylactic acid (PLA). 
     
     
         4 . The geotextile of  claim 1  wherein the natural fibers are comprised of coconut fibers. 
     
     
         5 . The silt fence of  claim 2 , with a water flow rate of about 6 to about 14 gallons per minute per square foot. 
     
     
         6 . The silt fence of  claim 2 , with a water flow rate of about 8 to about 11.5 gallons per minute per square foot. 
     
     
         7 . The silt fence of  claim 2 , wherein the geotextile prior to use weighs about 80 g/m 2 . 
     
     
         8 . The geotextile of  claim 1  with a first sheet layer apparent opening size (AOS) in the range between about 20 and about 100 US Standard Sieve. 
     
     
         9 . The geotextile of  claim 1  with a first sheet layer apparent opening size (AOS) in the range between about 40 and about 70 Standard Sieve. 
     
     
         10 . The geotextile of  claim 1  with a first sheet layer apparent opening size (AOS) of about 70 US Standard Sieve. 
     
     
         11 . The geotextile of  claim 1  with a second sheet layer aperture size in the range of about 1/32″× 1/32″ to about ⅛″×⅛″. 
     
     
         12 . The geotextile of  claim 1  with a second sheet layer aperture size of about 1/16″× 1/16″.