Date of Degree
MS (Master of Science)
Civil and Environmental Engineering
William E. Eichinger
Particulate matter expelled from tunnel-ventilated animal feeding operations (AFOs) is known to transport malodorous compounds. As a mitigation strategy, vegetative environmental buffers (VEBs) are often installed surrounding AFOs in order to capture particulates and induce lofting and dispersion. Many farmers are or are interested in implementing VEBs, yet research supporting their efficacy remains sparse.
Currently, point measurements, often combined with models, are the primary means by which emission rates from AFOs and VEB performance has been investigated. The existing techniques lack spatial resolution and fail to assign the observed particulate reduction to capture, lofting, or dispersion.
In recent years, lidar has emerged as a suitable partner to point measurements in agricultural research. Lidar is regarded for its ability to capture entire plume extents in near real time. Here, a technique is presented for estimating the capture efficiency of a VEB using lidar. An experiment was conducted in which dust was released upwind of a VEB at a known rate, and the emission rate downwind of the VEB was estimated using an elastic scanning lidar. Instantaneous lidar scans showed periodic lofting well above the VEB, but when scans were averaged over several hours, the plumes appeared Gaussian. The experiment revealed a capture efficiency ranging from 21-74β, depending on the time of day. The methodology presented herein addresses deficiencies in the existing techniques discussed above, and the results presented add to the lacking body of research documenting VEB capture efficiency.
Over the last few decades, advances in mechanical, biological, and chemical technologies have allowed single farms to manage larger numbers of animals. As a result, every sector of animal husbandry has shifted toward large-scale production. Large-scale production increases efficiency and reduces cost, but the practice concentrates animals onto smaller plots of land, concentrating sources of animal-derived pollution. Many pollutants, such as ammonia and dust, are emitted into the air in high concentrations and carried downwind to neighboring communities. Research has even shown that odorous compounds are carried by dust particles, and if we can limit the amount of dust emitted, then we can limit odor problems in many rural areas.
Many farmers are interested in building tree buffers surrounding their facilities to help reduce the impact of odors to neighboring communities. These tree buffers are known as “vegetative environmental buffers”, and they filter dust from the air before it is allowed to travel further downwind. However, there is limited knowledge on how effective buffers are at capturing dust, and current methods to measure effectiveness are unreliable. We used lidar (laser radar) to scan a dust plume downwind of a buffer. We found that the buffer captured between 21 and 74% of the dust that passed through it, depending on the time of day. It performed best at night and worst during the day.
publicabstract, CAFO, emissions, lidar, particulate, remote sensing, vegetative environmental buffer
Copyright 2016 William Brandon Willis