2011 Annual Report
1a.Objectives (from AD-416)
A field study will be conducted to evaluate the effectiveness of a vegetative treatment system (VTS) in removing nutrients, pathogens and fecal indicator microorganisms, and hormones in the runoff from a beef cattle feedlot in central Nebraska over a two-year period. Collaborations with University of Nebraska, Lincoln (UNL) engineers and scientists will be utilized to accomplish this research objective. Two sub-objectives have been developed to answer key questions about the effectiveness of the VTS system. These sub-objectives are:
1. Evaluate the removal efficiency of the VTS during standard operation.
2. Determine the vertical movement and persistence of nutrients and pathogens and fecal indicator organisms within the VTA.
1b.Approach (from AD-416)
Sub-objective #1, Normal VTS operation: …during 2010 and 2011… [add to the end]--Pooled samples of ‘clean’ rainwater runoff (two per event), feedlot runoff (four per event) and excess infiltration runoff (two per event) will be analyzed in the University of Nebraska Water Science Laboratory for hormones (nearly three dozen, including estradiols, testosterones, progesterones, estriols, and trenbolone) and antibiotics (tetracyclines/sulfonamides and macrolide/betalactams). These samples will also be screened for resistance the third generation antibiotic ceftiofur that is widely used in cattle (Excede, Naxcel) for problems such as foot rot or eye infections.
Sub-objective #2, Movement and persistence of nutrients and pathogens and fecal indicator organisms: Once each year, wastewater will be applied to four of the VTA treatment cells followed by collection of surface soil samples from five sites within each of the four cells and then sample those sites periodically over two weeks in order to understand how constituents in the wastewater are utilized, transformed, or removed. Soil depth profiles down to 30 cm (5 cm increments) will also be determined at those five sites in each of the four cells to help gauge the downward movement of microbes and nutrients. The 30-cm soil profile will be collected once each year to determine the movement of constituent over the two-year study.
Initial field work collecting water and soil samples was conducted at the vegetative treatment area this past year. This area receives runoff from cattle feedlot pens for forage grass production and is designed to manage the nutrients and potential pathogens present in feedlot runoff. Samples associated with two rainfall events and one simulated clean water application were collected and analyzed immediately for nutrients, pathogens, pathogen indicators, and antibiotic resistant microorganisms. Subsamples were frozen and subsequently analyzed for pharmaceutically active compounds. A set of deep soil cores were also collected from twenty sites to investigate the movement of contaminants into the soil profile. Continued work is planned at the site with ammonia and greenhouse gas emissions collected in upcoming runoff applications.