Date of Graduation

2018

Document Type

Thesis

Degree Type

MS

College

Davis College of Agriculture, Natural Resources and Design

Department

Division of Plant and Soil Sciences

Committee Chair

Louis M. McDonald

Committee Co-Chair

Tom J. Basden

Committee Member

Ember M. Morrissey

Abstract

Excess nutrient runoff, nitrates and phosphates, has led to the development of algal blooms and hypoxic zones worldwide. Based on a report from the Chesapeake Bay Foundation nearly half of all nutrient sources originate from agricultural production with a quarter of this resulting from improper management of manures. This project focuses on a novel adaption of a denitrifying bioreactor, which has demonstrated removals of agricultural nutrients, which may have implications on the treatment of manure nutrients. These subsurface bioreactors work by providing a substrate, usually wood based, to act as a carbon source to support denitrifying bacteria which in turn systematically convert nitrate to nitrogen gas via microbial denitrification. In recent years biochar products have shown some effect on the leaching of soil nutrients and may aid in capturing nutrients in these bioreactors. For this study, a hardwood mix was chosen as the carbon substrate with 2 treatments of biochar additions at 10% and 50% by weight. Samples times of 0, 1, 4, 8, 12, 16, and 24 hours were collected then evaluated for total Kjeldahl nitrogen, nitrate, pH, EC, as well as, total and inorganic phosphorus, and calcium. Overall, nitrate concentration did not decrease over time, and there was no significant reduction in phosphorus. Based on the data collect, additional testing may need to be done in order to determine the effectiveness of a denitrifying bioreactor in treating manure sourced nutrients.

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