Field applicable agricultural surface runoff treatment via activated carbon filters (NEW)

Nazli Yilmaz Wodzinski

Artificial subsurface (or tile) drainage is a common agricultural practice in Minnesota along with many other states along the Mississippi River Drainage Basin. In 2017, 22.5 million hectares of rural croplands were tile-drained; 84% of these lands are mainly in six Midwestern States on the Mississippi Basin. Although it is important to the agricultural community and makes sense economically, this method has a negative impact on basin hydrology and quality of the receiving waters. The drainage water in agricultural ditches carries excess nutrients (especially nitrogen and phosphorus) and decreases the quality of the receiving waters. Historic data points out that subsurface drainage increases nitrogen concentration while surface drainage increases the suspended sediment and phosphorus concentration of the discharged water. However, in early spring, the agricultural fields are thawed, newly fertilized (high in nutrients), bare and vulnerable to erosion. Historic data shows that the suspended sediment and concentrations of both nutrients peak regardless of drainage system type. These peaks are specifically observed during early spring rainfall events.

The objective of this proposed research project is to propose a practical and field applicable best management practice that will be decrease the concentrations of suspended sediment, nitrogen, and phosphorus. Our goal is to accomplish remarkable treatment for the average volumetric flow rate of the effluent (ditch water with excess nutrient) without interrupting the flow and accumulating water on site. For the proposed best management practice, we will use activated carbon and flocculation agents as filter media.