Biological Systems Engineering
Pius Ndegwa
Addressing the Environmental Concerns of Animal Agriculture
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Animal manure is a resource that can provide valuable organic material and nutrients for crop and pasture production, but in excessive amounts, nutrient runoff can leach from the soil to degrade water quality. To control water pollution, federal regulations require large animal feeding operations (AFOs) to meet nutrient application standards when fertilizing crops and pastures with manure. For large regional animal agriculturalists to comply with these regulations, they need to either export the manure, which is bulky and expensive to haul, or find alternate uses for it. Dr. Ndegwa’s research focuses on both aspects of this problem. By packaging manure nutrients in compact forms, he has devised a way to economically export it to remote areas; his research also focuses on the development of biofuels from this resource.
Besides the volume issue, another major concern is in the imbalance of the vital nutrients nitrogen (N) and phosphorus (P) in manure. In general, land application of animal manure has traditionally been based on nitrogen content. However, plants N:P requirements are approximately 8:1 for major grain and hay crops, while most animal manures usually contain nitrogen and phosphorus in the ratio of 4:1. Thus, nitrogen based land applications usually lead to over-application and subsequent accumulation of phosphorus in the receiving soils, a situation that threatens both soil and water qualities. Dr. Ndegwa is working to develop treatment processes to balance nitrogen and phosphorus in animal manure to match specific crop requirements.
Dr. Ndegwa’s research also focuses on developing technologies and methods to objectively detect and measure odor, particulate matter, and other gaseous emissions associated with animal production. Air pollutants such as these emitted from AFOs can create neighborhood nuisances as well as animal and human health concerns. An assessment of the true impact of these air pollutants is limited by a lack of reliable data on emission rates. This lack of information impedes: the development of air emission control technologies; the use of modeling to assess the impact of emissions; and the formation of practical federal, state, and local regulations. Dr. Ndegwa hopes to develop control technologies and systems to abate and/or eliminate the generation of these air pollutants.
Contact
Information
Pius Ndegwa, Ph.D.
Assistant Professor
Biological Systems Engineering
Washington State University
PO Box 646120
Pullman, WA 99164-6120
Telephone: 509-335-8167
E-mail: ndegwa@wsu.edu
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