Page Banner

United States Department of Agriculture

Agricultural Research Service

Laboratory Assessment of Filter Materials
headline bar

Objective:  Laboratory testing to indentify industrial product/byproduct filter materials having the potential to remove mixed nutrient and pesticide contaminants from agricultural drainage waters.  To be feasible for use, the most promising industrial products/byproducts must also be proven to have the hydraulic capacity to allow a sufficient rate of drainage water flow.

Approach:   Batch tests have been used to screen a wide variety of industrial products/byproducts with respect to nitrate, phosphate, and atrazine removal potential.  Additional batch tests provided insight on the nutrient/pesticide removal effectiveness and efficiency for the most promising materials isolated during the screening phase.  Saturated hydraulic conductivity tests were employed to evaluate the water flow capacity of the most promising materials.  Saturated solute transport column tests were then conducted to assess the contaminant removal abilities of the best filter materials under conditions more realistically similar to those of an actual filter treatment system.


  • Over sixty industrial products/byproducts have been evaluated, and several of these show strong potential for use in filters to remove agricultural contaminants from drainage waters.
  • Sulfur modified iron, a relatively unknown industrial product, has proven to be the best candidate for nitrate removal (50% to 100% reduction during column tests).  A steam activated carbon and a ground iron aggregate (zero valent iron) seem to work well removing the pesticide, atrazine (90% to 100% reduction during column tests).  All three of these materials are capable of removing phosphate (90% to 100% reduction during column tests).
  • A filter treatment system containing a combination of the materials evaluated might be the optimal choice for removing mixed contaminants from drainage waters; however, additional laboratory tests followed by field trials are required.



Cooperators:  SMI_PS, Inc., North American Hoganas, Inc.

For additional Information:   

Barry J. Allred
USDA/ARS - Soil Drainage Research Unit
590 Woody Hayes Drive, RM. 234
Columbus, Ohio  43210
Phone:  614-292-9806
Fax:  614-292-9448

Last Modified: 8/13/2016
Footer Content Back to Top of Page