PERFORMANCE OF A PASSIVE FEEDLOT RUNOFF CONTROL AND TREATMENT SYSTEM

摘要

The recent signing of the NPDES permit regulations and effluent limitations guidelines for CAFO has generated much interest from smaller beef cattle feeding operations for a more cost-effective solution for managing feedlot runoff. A passive runoff control and treatment system was constructed to reduce long-term liquid storage, provide solids separation, and evenly distribute the liquid discharge for grass hay production. The overall objective of this study was to evaluate the effectiveness of this passive system for reducing contaminant discharge. The system effectively reduced the cumulative mass of total and volatile suspended solids and reduced chemical oxygen demand by 80%, 67%, and 59%, respectively. Significant reductions of these constituents in the runoff water as it passed through the system were measured for most precipitation events. No water was measured exiting the vegetative filter strip during the three-year period of this study. Therefore, the discharge water was effectively contained and used for hay crop production. Estimated total nitrogen (TN) load in the discharge water entering the vegetative filter strip was equivalent to or less than the TN removed by the crop. System robustness was demonstrated during feedlot pen renovation when significant reductions in contaminant concentrations were measured for most all precipitation events during that period