For more: http://www.extension.org/67605 In livestock producing areas, animal manure is often applied to cropland to enhance soil fertility. Guidelines have been developed for manure application on fields underlain by subsurface (tile) drainage systems. Some of these guidelines, such as avoiding manure application if rain is predicted and not applying manure over a flowing tile, though effective, involve some level of risk. We believe that the level of risk can be reduced by filtering contaminants from the water leaving the drains. The control structures recommended for use with drainage systems underlying fields to which manure is applied, provide ready-made receptacles for filters. In this report we discuss the development and testing of a filter to remove contaminants from lagoon effluent.