Manure Flushing Versus Scraping In Dairy Freestall Lanes Reduces Gaseous Emissions

Author : Rylie Jo Ellison
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.6/5 (912 download)

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Download or read book Physicochemical Transformations of Manure to Reduce Greenhouse Gas Emissions, Improve Nutrient Use, and Minimize Environmental Impacts of Dairy Operations written by Rylie Jo Ellison and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Storage and agricultural applications of manure often result in significant loss of carbon, nitrogen, and phosphorus to the environment through volatilization and leaching. In California, manure management is estimated to be the largest source of greenhouse gas emissions from agriculture, mainly as methane (CH4) and nitrous oxide (N2O), with dairy operations being a key contributor. One of the main challenges with using animal wastes as nutrient sources is the unpredictable nitrogen mineralization rate for crop uptake. Many dairies limit application of manure organic nitrogen to prevent groundwater contamination. With a large range of dairy sizes and types of manure management systems in California, there is also a need for a variety of manure treatment technologies to address these problems. Treatments examined in this dissertation are two physicochemical techniques: chemical solid-liquid separation (coagulation) and hydrodynamic cavitation with chemical stabilization. Physically and chemically transforming animal wastes to exhibit a predictable nitrogen mineralization response is an important research and development priority. Generating a stabilized and easily transportable fertilizer from manure can help reduce environmental concerns related to on-farm nutrient management and enhance the economic feasibility for dairies. Enhancing solid-liquid separation with chemical coagulants traditionally used in wastewater treatment can isolate dissolved and particulate organic matter and phosphorus from manure into stabilized solids (flocs) while leaving the plant-available ammonium-N in the liquid fraction (effluent). In this research, a range of coagulants, including metal salts and organic polymers were tested with multiple dairy process wastewaters. The effects of chemical coagulation on the composition of the separated manure fractions, and the resulting impact on greenhouse gases and nutrient cycling are extensively explored through a series of laboratory incubations of manure effluents and manure-amended soils. Anaerobic incubations of the effluent fractions were performed to determine how both removing coagulated solids from manure process wastewater or leaving coagulated manure flocs in anaerobic storage affects greenhouse gases, CH4 in particular. This simulates how greenhouse gases from anaerobic storage ponds, or lagoons, on dairies would be affected by this treatment practice. In each incubation, regardless of coagulant type or separation of solids, CH4, and/or CO2 and N2O were significantly reduced. Several aerobic soil incubations simulated how adding coagulated manure flocs or effluents would impact the nutrient cycling of chemically separated manures applied to agricultural soils. Coagulation generally tended to stabilize organic matter, and slow C, N, and P mineralization of the solid floc fraction, depending on the type of coagulant used. This could potentially increase C sequestration and reduce nutrient runoff on dairies; however, farmers would need to manage for less nutrient availability. Lastly, the potential for hydrodynamic cavitation to be employed in a dairy manure treatment system was explored. The effects of hydrodynamic cavitation on manure were to break down organic matter and increase nitrogen availability, which could help in regulating the rate of nitrogen mineralization from manure. Hydrodynamic cavitation is also used for sterilization, which could be another benefit for manure applications. However, further work is needed to determine the efficacy of hydrodynamic cavitation for treating manure at a larger scale.