Effects of infiltration beneath a waste stabilization pond
Garza, Mari Elise
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The Texas High Plains area has a large cattle feedlot industry that has developed in the past 25 years that is believed to be a potential polluter of the surface water and groundwater supplies in the Texas High Plains. It is believed a natural liner can be formed when manure is placed on top of soil in an agricultural wastewater lagoon. This project focused primarily on the infiltration characteristics beneath an agricultural wastewater treatment pond. The soil found beneath an agricultural pond in New Deal, Texas was used in a laboratory experiment to study the infiltration rates through soil and manure layers. A qualitative analysis was completed to determine the ways in which nitrogen is used by the microbes in the natural sealing process. Analysis of the infiltration data reveal that in less than two months the infiltration rate decreased from an average of 3.53 x 10" cm/sec to less than 1 x 10' cm/sec. The 1x10' cm/sec is the infiltration rate maximum allowed by the Environmental Protection Agency (EPA). A manure depth of 2" to 12" did not impact the time to slow the infiltration rate. But the manure and the soil had to be present to slow or stop infiltration because the columns with no manure could not retain any water. The qualitative analysis revealed that the majority of the nitrogen in the column was in the form of TKN and ammonia. The more manure in the column the higher the concentration of total nitrogen. A mathematical model was developed to describe the non-linear flmction of the flow pattern of hydraulic conductivity over time. The model was highly significant to the fit of the data collected from the columns. All the R" values obtained by the mathematical model were greater than 0.95.