糖心视频

Funding: South 糖心视频 Pork Producers Association 

Project members:

• Dick Nicolai, associate professor
• Steve Pohl, professor
• Ryan Lefers, graduate research assistant
   

Odors from livestock facilities are an issue for many communities and livestock producers. Air quality effects from livestock operations have become an environmental, ecological and sociological problem. Emissions for gases and particulates from livestock operations are considered to be environmental impacts that must be controlled. Odor sources for livestock production systems include buildings, manure storage and land application of manure. Most complaints have focused on emissions from uncovered outside manure storage. Therefore, the current trend in swine production is to use deep pit manure storage beneath the slatted floor. In this situation, the livestock building becomes a major odor source. Biofiltration is an odor-reduction technique that can be adapted to reduce emissions from these mechanically ventilated facilities. 

For biofiltration to be successful, significant land area is needed to effectively treat most, if not all, the exhaust air. For example, to treat 60% of the maximum summer ventilation rate of a 1,000-head finisher barn, the required land area can equal up to half the size of the building. This approach works well for newly designed facilities, but there are many existing building locations that do not allow for such an area. 

Completed, and the current report is "Design Specification for a Vertical Bed Biofilter."

Media thickness was determined to be a factor in achieving uniform airflow. For biofilters of 12 and 24 inches think, a wall taper of 9.6 degrees produced the least airflow variation at the end of one year as compared to a wall slope of 0 and 4.8 degrees. Improved media moisture distribution was achieved when the water soaker hose was placed on top of the media versus being suspended vertically through it. The value of this research leads to a more efficient vertical biofilter design configuration.

Funding: South 糖心视频 Pork Producers Association

Project Members:

• Dick Nicolai, associate professor
• Steve Pohl, professor
• Ryan Lefers, graduate research assistant
• Sriramulu Pasikanti, electronics coordinator

Livestock and poultry odors and airborne emissions are a concern in many communities throughout South 糖心视频. Odors from livestock facilities can be reduced by diluting and/or enhancing the dispersion of the odorous gases leaving the livestock site. Rows of trees and other vegetation known as shelterbelts may have value as odor control devices by increasing odor dispersion. Shelterbelts are vegetation systems that typically use trees and shrubs to redirect wind and reduce wind speeds, thereby modifying environmental conditions within the upwind and downwind sheltered zones. Livestock producers and local government units are seeking information on the effectiveness of shelterbelts to reduce odors and gas emissions.

Completed, and final report is "Natural Windbreak Effect on Livestock Hydrogen Sulfide Reduction."

For all wind speeds, a mature windbreak reduces H2S concentration levels at all wind speeds an average of 85% at a point approximately 100 feet beyond the windbreak. When average for all wind speeds, an immature windbreak, i.e. trees 10 to 115 feet tall, did not statistically significantly reduce H2S concentration levels. 

At very slow wind speeds (0 to 5 mph), both immature and mature windbreaks reduced H2S concentration levels. Above 10 mph wind speeds, the H2S concentration levels were not significantly different between no windbreak, an immature windbreak and a mature windbreak i.e. whether the windbreak was in place or not there was no change in hydrogen sulfide reduction. 

Funding: High Plains Intermountain Center for Agricultural Health and Safety

Project Members: Dick Nicolai, associate professor; Sarah Smith, graduate research assistant

A manure pit is a confined-space hazard that often claims multiple lives before anyone realizes there is a danger in manure gas. Many farm workers appear to be unaware of the immediate danger posed by entry into manure pits. Like other types of confined spaces, manure pits present special problems regarding worker awareness of hazards. Manure pits can be oxygen-deficient, toxic and explosive. Hydrogen sulfide is one gas in manure pits that is of primary concern. Hydrogen sulfide is a highly toxic gas that is heavier than the air that sinks to the bottom of the head space in a manure pit. It can cause dizziness, unconsciousness and death. At low concentrations, it may smell like rotten eggs, but at high concentrations, it deadens the sense of smell so that no odor can be detected. 

Completed, and final report is "Hydrogen Sulfide Reduction of Swine Manure using Potassium Permanganate and Hydrogen Peroxide."

Adding a metallic salt to the manure reduces the hydrogen sulfide emissions. The salt impacts the sulfur cycle and therefore reduces hydrogen sulfide production but not volatile fatty acid production. Ferrous chloride and hydrogen peroxide are several salts that have shown promise to reduce hydrogen sulfide emissions. Two trials of H₂O₂  and two trials of KMnO₄ were performed. In each trial, H₂S was reduced by at least 91%. With the second trial of H₂O₂, H₂S, concentration in the headspace was reduced from 50 ppm to 0.38 ppm in six minutes. Additional research is needed to prove the amount of chemicals to add to ensure safe entry of the pit.