Date of Award
Master of Science
Agricultural and Biosystems Engineering
Robert T. Burns
Matthew J. Helmers
Runoff from open beef feedlots has become an important environmental concern over the last decade. Feedlot runoff has the potential to degrade surface water and groundwater. For these reasons, the U.S. Environmental Protection Agency required concentrated animal feeding operations (CAFOs) to control feedlot runoff resulting from up to and including a 25 year, 24 hour rainfall event. Typical feedlot runoff control systems utilize a containment basin to collect and store feedlot runoff.
In 2003, federal regulations allowed the use of alternative technologies to control feedlot runoff that performed equal to or better than a conventional runoff storage basin on a pollutant mass released basis. Vegetative treatment systems (VTS) are one alternative technology system of interest to researchers and producers across the Midwest. These systems utilize a solid settling basin (SSB), vegetative treatment area (VTA), and an optional vegetative infiltration basin (VIB). During a runoff event, earthen berms collect and convey feedlot runoff (i.e., effluent) into a SSB where a fraction of the solids are removed via settling. After solids are settled, the effluent is then applied to a VTA where it is infiltrated into the soil where plant uptake and treatment occur. Beef producers in the Midwestern United States have shown an increasing interest in using VTSs as a perceived lower cost option to traditional containment basin systems.
This thesis includes two papers for journal submission and one supplemental chapter providing further analysis of the first paper. Chapter two consists of the first paper titled "Comparison of construction costs for vegetative treatment systems in the Midwestern United States" while chapter three is titled "Evaluating the annualized vegetative treatment system cost." Chapter four consists of the second paper is titled "Evaluating the performance of vegetative treatment systems on open beef feedlots in the Midwestern United States."
Chapter two, including the first paper, reports the construction cost associated with 23 VTSs located in the Midwestern United States. The cost comparison for VTSs were presented on a per head space of cattle basis adjusted to 2009 dollars for animal feeding operations (AFOs) containing less than 1,000 head of cattle and CAFOs containing more than 1,000 head of cattle.
VTS construction costs were compared to estimated construction costs associated with conventional basins, monoslope barns, hoop structures, and earthen feedlots with a basin system. Results from the cost comparison indicated VTSs on average were the least expensive runoff control system to construct compared to conventional containment basins on both AFO ($77 per head space for VTS, $205 per head space for containment basin) and CAFO ($85 per head space for VTS, $136 per head space for containment basin) facilities. The construction cost of a VTS implemented on an open feedlot was compared to a monoslope barn, hoop structure, and open feedlot with a containment basin. In this analysis, the VTS constructed with an open earthen feedlot was, on average, the least expensive feedlot system to construct at $282 per head space of cattle (average of feedlot size) followed by an open lot with containment basin ($361 per head space of cattle), hoop structure ($395 per head space of cattle), and monoslope barn ($655 per head space of cattle).
The third chapter reports the annualized cost associated with the initial construction of a VTS compared to a containment basin. Operation and maintenance costs were not included for either VTSs or containment basins in this analysis due to availability of data. Results from this analysis showed VTSs, on average, cost approximately $13 per head space on an annualized basis. This value assumes a life expectancy of 10 years. An estimated conventional basin designed for the same VTSs would cost approximately $11 per head space on an annualized basis for a basin life expectancy of 25 years and an irrigation equipment life expectancy of 10 years. A VTS break even life expectancy of greater than 14 years was needed to create an annualized system cost less than a conventional basin. Annualized system cost was found to be largely influenced by life expectancy.
Chapter four consisting of the second paper reports the 2009 VTS performance data collected from nine CAFO feedlots located in Iowa, Nebraska, and Minnesota. The nine VTSs were compared on the total runoff volumes from the SSB and VTA, pollutant concentrations in the effluent released from the VTA, and the mass of five monitored parameters released from each VTS component.
In 2009, five of the nine monitored VTSs did not report a release from the VTS. The percent runoff controlled varied by site ranging from a low of -6 percent to a high of 100 percent. The overall average percent of mass reduced from the five monitored parameters ranged from 72 to 100 percent. Vegetative treatment systems performance varied depending on site specific rainfall, stocking densities, feedlot to VTA ratio, and system design. The concentrations of five runoff parameters were monitored leaving each VTS component. These five parameters were total Kjeldahl nitrogen, ammonia, total phosphorus, chemical oxygen demand, and total solids. The 2009 overall average concentration reduction for each VTS ranged from 35% to 84%. This range in concentration reductions was due to VTS design, weather conditions, site variation (i.e., soils, vegetation, etc.), and management practices.
Bradley J. Bond
Bond, Bradley J., "Evaluating the cost and performance of vegetative treatment systems on open beef feedlots in the Midwestern United States" (2010). Graduate Theses and Dissertations. 11568.