Thesis
CHARACTERIZATION OF THE ENVIRONMENTAL IMPACT AND ECONOMIC ANALYSIS OF A VERMIFILTRATION SYSTEM USED TO TREAT LIQUID DAIRY CATTLE MANURE
Washington State University
Master of Science (MS), Washington State University
05/2024
DOI:
https://doi.org/10.7273/000006958
Abstract
Improper handling and disposal of manure can result in environmental problems, such as water contamination, soil degradation, and release of greenhouse gases (GHG) and ammonia (NH3), posing challenges to the dairy industry. Technologies such as vermifiltration have been proposed as an effective solution. Vermifiltration treats wastewater aerobically through gravity filtration and microbial metabolism in a layered biofilter system inoculated with worms. The system used in this study treated 946,000 L of liquid cattle manure daily from 9580 head of dairy cattle. The objective was to characterize the environmental and economic characteristics of a commercial vermifiltration system. Methane (CH4), nitrous oxide (N2O), and NH3 emissions were quantified. Additionally, the chemical and physical nutrient composition (potassium-K, phosphorus-P, nitrogen-N, other mineral, carbon, solids, and pH) of dairy wastewater and vermibed materials were examined. These data were also used to determine the economic feasibility of the system compared to other dairy manure systems. Methane, N2O, and NH3 surface fluxes were measured at several locations in the 2.98 ha system and four ambient temperatures (0˚C, 10˚C, 20˚C, and 25˚C) using surface flux isolation chambers. Bed location and temperature affected the fluxes of each gas. Methane and N2O emissions were lowest at 0˚C and increased by 90% and 74%, respectively as temperature increased. Ammonia emissions were nonexistent at 0˚C and increased 99% as temperature increased to 25˚C. Reductions of 68% in total N, 72% in phosphates, 54% in total carbon, 75% in total suspended solids, and a 6% increase in K were observed in influent compared to effluent. Copper, magnesium, zinc, iron, and manganese were reduced in concentration in influent compared to effluent water. Flux calculations and extrapolation of emission rates to the entire system indicate that vermifiltration reduces CH4 and N2O emissions but not NH3 emissions compared to other reported literature of traditional dairy manure handling systems. Implementation of vermifiltration can benefit whole farm economics via sales of carbon credits and nutrient rich bed material, and through the creation of uniform effluent water for crop growth. Revenue generated from carbon credits can be up to $1,594,600 annually, and revenue from vermicompost can provide an additional $4,548,155 biannually. This study highlights the potential for vermifiltration to transform dairy manure handling by altering nutrient cycling and impacting whole farm economics.
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Details
- Title
- CHARACTERIZATION OF THE ENVIRONMENTAL IMPACT AND ECONOMIC ANALYSIS OF A VERMIFILTRATION SYSTEM USED TO TREAT LIQUID DAIRY CATTLE MANURE
- Creators
- Jera Lynn Monaghan
- Contributors
- Kristen A Johnson (Chair)B. Thomas Jobson (Committee Member)Margaret E Benson (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Department of Animal Sciences
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University
- Number of pages
- 180
- Identifiers
- 99901125240501842
- Language
- English
- Resource Type
- Thesis