Evaluation of Phosphorus Filter Media for an In-Line Tile Drainage Treatment System

Abstract. In the Midwest a large percentage of crop land utilizes tile drainage.  It is an effective management method to remove excess water from agricultural fields which promotes healthy crop growth and yield.  However, while these systems are beneficial, they can also provide a direct passage for phosphorus and nitrogen to enter into surrounding surface waters.  These nutrients, when introduced to surface waters, can cause poor water quality issues.  This research will evaluate the potential for an in-line treatment system to reduce phosphorus export to surface water.  The focus of the study will be placed on evaluating different filter media, including blast furnace slag, expanded shale, expanded clay, and an iron rich sandy loam soil. Evaluation of media was conducted in laboratory using batch and column testing methods. The information from the data presented will aid in the development of an in-line treatment system for tile drainage systems.